@article{PrieskeMuehlbauerMuelleretal.2013, author = {Prieske, Olaf and M{\"u}hlbauer, Thomas and M{\"u}ller, Steffen and Kr{\"u}ger, Tom and Kibele, Armin and Behm, David George and Granacher, Urs}, title = {Effects of surface instability on neuromuscular performance during drop jumps and landings}, series = {European journal of applied physiology}, volume = {113}, journal = {European journal of applied physiology}, number = {12}, publisher = {Springer}, address = {New York}, issn = {1439-6319}, doi = {10.1007/s00421-013-2724-6}, pages = {2943 -- 2951}, year = {2013}, abstract = {The purpose of this study was to investigate the effects of surface instability on measures of performance and activity of leg and trunk muscles during drop jumps and landings. Drop jumps and landings were assessed on a force plate under stable and unstable (balance pad on top of the force plate) conditions. Performance measures (contact time, jump height, peak ground reaction force) and electromyographic (EMG) activity of leg and trunk muscles were tested in 27 subjects (age 23 +/- A 3 years) during different time intervals (preactivation phase, braking phase, push-off phase). The performance of drop jumps under unstable compared to stable conditions produced a decrease in jump height (9 \%, p < 0.001, f = 0.92) and an increase in peak ground reaction force (5 \%, p = 0.022, f = 0.72), and time for braking phase (12 \%, p < 0.001, f = 1.25). When performing drop jumps on unstable compared to stable surfaces, muscle activity was reduced in the lower extremities during the preactivation, braking and push-off phases (11-25 \%, p < 0.05, 0.48 a parts per thousand currency sign f a parts per thousand currency sign 1.23). Additionally, when landing on unstable compared to stable conditions, reduced lower limb muscle activities were observed during the preactivation phase (7-60 \%, p < 0.05, 0.50 a parts per thousand currency sign f a parts per thousand currency sign 3.62). Trunk muscle activity did not significantly differ between the test conditions for both jumping and landing tasks. The present findings indicate that modified feedforward mechanisms in terms of lower leg muscle activities during the preactivation phase and/or possible alterations in leg muscle activity shortly after ground contact (i.e., braking phase) are responsible for performance decrements during jumping on unstable surfaces.}, language = {en} } @article{AhmadiHeratAlizadehetal.2021, author = {Ahmadi, Hamid and Herat, Nehara and Alizadeh, Shahab and Button, Duane C. and Granacher, Urs and Behm, David G.}, title = {Effect of an inverted seated position with upper arm blood flow restriction on measures of elbow flexors neuromuscular performance}, series = {PLOS ONE / Public Library of Science}, volume = {16}, journal = {PLOS ONE / Public Library of Science}, number = {5}, publisher = {PLoS}, address = {San Fransisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0245311}, pages = {19}, year = {2021}, abstract = {Purpose The objective of the investigation was to determine the concomitant effects of upper arm blood flow restriction (BFR) and inversion on elbow flexors neuromuscular responses. Methods Randomly allocated, 13 volunteers performed four conditions in a within-subject design: rest (control, 1-min upright position without BFR), control (1-min upright with BFR), 1-min inverted (without BFR), and 1-min inverted with BFR. Evoked and voluntary contractile properties, before, during and after a 30-s maximum voluntary contraction (MVC) exercise intervention were examined as well as pain scale. Results Inversion induced significant pre-exercise intervention decreases in elbow flexors MVC (21.1\%, Z2p = 0.48, p = 0.02) and resting evoked twitch forces (29.4\%, Z2p = 0.34, p = 0.03). The 30-s MVC induced significantly greater pre- to post-test decreases in potentiated twitch force (Z2p = 0.61, p = 0.0009) during inversion (75\%) than upright (65.3\%) conditions. Overall, BFR decreased MVC force 4.8\% (Z2p = 0.37, p = 0.05). For upright position, BFR induced 21.0\% reductions in M-wave amplitude (Z2p = 0.44, p = 0.04). There were no significant differences for electromyographic activity or voluntary activation as measured with the interpolated twitch technique. For all conditions, there was a significant increase in pain scale between the 40-60 s intervals and post-30-s MVC (upright< inversion, and without BFR< BFR). Conclusion The concomitant application of inversion with elbow flexors BFR only amplified neuromuscular performance impairments to a small degree. Individuals who execute forceful contractions when inverted or with BFR should be cognizant that force output may be impaired.}, language = {en} } @article{LesinskiHerzSchmelcheretal.2020, author = {Lesinski, Melanie and Herz, Michael and Schmelcher, Alina and Granacher, Urs}, title = {Effects of resistance training on physical fitness in healthy children and adolescents}, series = {Sports medicine}, volume = {50}, journal = {Sports medicine}, number = {11}, publisher = {Springer}, address = {Northcote}, issn = {0112-1642}, doi = {10.1007/s40279-020-01327-3}, pages = {1901 -- 1928}, year = {2020}, abstract = {Background Over the past decades, an exponential growth has occurred with regards to the number of scientific publications including meta-analyses on youth resistance training (RT). Accordingly, it is timely to summarize findings from meta-analyses in the form of an umbrella review. Objectives To systematically review and summarise the findings of published meta-analyses that investigated the effects of RT on physical fitness in children and adolescents. Design Systematic umbrella review of meta-analyses. Data Sources Meta-analyses were identified using systematic literature searches in the databases PubMed, Web of Science, and Cochrane Library. Eligibility Criteria for Selecting Meta-analyses Meta-analyses that examined the effects of RT on physical fitness (e.g., muscle strength, muscle power) in healthy youth (<= 18 years). Results Fourteen meta-analyses were included in this umbrella review. Eleven of these meta-analyses reported between-subject effect sizes which are important to eliminate bias due to growth and maturation. RT produced medium-to-large effects on muscle strength, small-to-large effects on muscle power, small-to-medium effects on linear sprint, a medium effect on agility/change-of-direction speed, small-to-large effects on throwing performance, and a medium effect on sport-specific enhancement. There were few consistent moderating effects of maturation, age, sex, expertise level, or RT type on muscle strength and muscle power across the included meta-analyses. The analysed meta-analyses showed low-to-moderate methodological quality (AMSTAR2) as well as presented evidence of low-to-very low quality (GRADE). Conclusion This umbrella review proved the effectiveness of RT in youth on a high evidence level. The magnitude of effects varies according to the respective outcome measure and it appears to follow the principle of training specificity. Larger effect sizes were found for strength-related outcome measures. Future studies should consistently report data on participants' maturational status. More research is needed with prepubertal children and girls, irrespective of their maturational status.}, language = {en} } @article{HelmPrieskeMuehlbaueretal.2018, author = {Helm, Norman and Prieske, Olaf and M{\"u}hlbauer, Thomas and Kr{\"u}ger, Tom and Granacher, Urs}, title = {Effects of judo-specific resistance training on kinetic and electromyographic parameters of pulling exercises in judo athletes}, series = {Sportverletzung, Sportschaden : Grundlagen, Pr{\"a}vention, Rehabilitation}, volume = {32}, journal = {Sportverletzung, Sportschaden : Grundlagen, Pr{\"a}vention, Rehabilitation}, number = {2}, publisher = {Thieme}, address = {Stuttgart}, issn = {0932-0555}, doi = {10.1055/s-0043-122781}, pages = {134 -- 142}, year = {2018}, abstract = {Background In judo, rapid force production during pulling movements is an important component of athletic performance, which is why this capacity needs to be specifically exercised in judo. This study aimed at examining the effects of a judo-specific resistance training program using a judo ergometer system (PTJ) versus a traditional resistance training regime using a partner (PTP) on kinetics and muscle activity of judo-specific pulling exercises. Method Twenty-four male judo athletes (age: 22 +/- 4 years, training experience: 15 +/- 3 years) were randomly assigned to two groups. In a crossover design, the first group completed a 4-week PTJ followed by four weeks of PTP (each with three sessions per week). The second group conducted PTP prior to PTJ. PTJ and PTP were completed in addition to regular training. Before, 4 weeks and 8 weeks after training, tests were conducted to assess judo-specific pulling kinetics (i.e. maximal force, rate of force development [RFD], mechanical work) and electromyographic (EMG) shoulder/trunk muscle activity (i.e. biceps brachii muscle, deltoid muscle, trapezius muscle, erector spinae muscle) during pulling movements using a judo ergometer as well as unspecific strength tests (i.e. bench-pull, pull-ups). Results The statistical analysis revealed that in both groups ergometer pulling kinetics (p<.05, 0.83 <= d <= 1.77) and EMG activity (p<.05; 1.07 <= d <= 2.25) were significantly enhanced following 8 weeks of training. In addition, significantly larger gains in RFD, mechanical work, and EMG activity (i.e. deltoid muscle, erector spinae muscle, trapezius muscle) were found following PTJ compared to PTP (p<.05, 1.25 <= d <= 2.79). No significant enhancements were observed with the unspecific strength tests. Conclusion Our findings indicate that PTJ is superior to PTP regarding training-induced improvements in force production and muscle activity during judo-specific pulling exercises. Performance enhancements may partly be attributed to neural adaptations. No transfer effects on unspecific strength tests were detected following PTJ and PTP.}, language = {de} } @misc{GaeblerBerberyanPrieskeetal.2022, author = {G{\"a}bler, Martijn and Berberyan, Hermine S. and Prieske, Olaf and Elferink-Gemser, Marije Titia and Hortobagyi, Tibor and Warnke, Torsten and Granacher, Urs}, title = {Strength Training Intensity and Volume Affect Performance of Young Kayakers/Canoeists}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1866-8364}, doi = {10.25932/publishup-54228}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-542283}, pages = {1 -- 10}, year = {2022}, abstract = {Purpose: The aim of this study was to compare the effects of moderate intensity, low volume (MILV) vs. low intensity, high volume (LIHV) strength training on sport-specific performance, measures of muscular fitness, and skeletal muscle mass in young kayakers and canoeists. Methods: Semi-elite young kayakers and canoeists (N = 40, 13 ± 0.8 years, 11 girls) performed either MILV (70-80\% 1-RM, 6-12 repetitions per set) or LIHV (30-40\% 1-RM, 60-120 repetitions per set) strength training for one season. Linear mixed-effects models were used to compare effects of training condition on changes over time in 250 and 2,000 m time trials, handgrip strength, underhand shot throw, average bench pull power over 2 min, and skeletal muscle mass. Both between- and within-subject designs were used for analysis. An alpha of 0.05 was used to determine statistical significance. Results: Between- and within-subject analyses showed that monthly changes were greater in LIHV vs. MILV for the 2,000 m time trial (between: 9.16 s, SE = 2.70, p < 0.01; within: 2,000 m: 13.90 s, SE = 5.02, p = 0.01) and bench pull average power (between: 0.021 W⋅kg-1, SE = 0.008, p = 0.02; within: 0.010 W⋅kg-1, SE = 0.009, p > 0.05). Training conditions did not affect other outcomes. Conclusion: Young sprint kayakers and canoeists benefit from LIHV more than MILV strength training in terms of 2,000 m performance and muscular endurance (i.e., 2 min bench pull power).}, language = {en} } @misc{PeitzBehringerGranacher2019, author = {Peitz, Matti and Behringer, Michael and Granacher, Urs}, title = {A systematic review on the effects of resistance and plyometric training on physical fitness in youth}, series = {Postprints der Universit{\"a}t Potsdam Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam Humanwissenschaftliche Reihe}, number = {498}, issn = {1866-8364}, doi = {10.25932/publishup-42220}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-422201}, year = {2019}, abstract = {Introduction To date, several meta-analyses clearly demonstrated that resistance and plyometric training are effective to improve physical fitness in children and adolescents. However, a methodological limitation of meta-analyses is that they synthesize results from different studies and hence ignore important differences across studies (i.e., mixing apples and oranges). Therefore, we aimed at examining comparative intervention studies that assessed the effects of age, sex, maturation, and resistance or plyometric training descriptors (e.g., training intensity, volume etc.) on measures of physical fitness while holding other variables constant. Methods To identify relevant studies, we systematically searched multiple electronic databases (e.g., PubMed) from inception to March 2018. We included resistance and plyometric training studies in healthy young athletes and non-athletes aged 6 to 18 years that investigated the effects of moderator variables (e.g., age, maturity, sex, etc.) on components of physical fitness (i.e., muscle strength and power). Results Our systematic literature search revealed a total of 75 eligible resistance and plyometric training studies, including 5,138 participants. Mean duration of resistance and plyometric training programs amounted to 8.9 ± 3.6 weeks and 7.1±1.4 weeks, respectively. Our findings showed that maturation affects plyometric and resistance training outcomes differently, with the former eliciting greater adaptations pre-peak height velocity (PHV) and the latter around- and post-PHV. Sex has no major impact on resistance training related outcomes (e.g., maximal strength, 10 repetition maximum). In terms of plyometric training, around-PHV boys appear to respond with larger performance improvements (e.g., jump height, jump distance) compared with girls. Different types of resistance training (e.g., body weight, free weights) are effective in improving measures of muscle strength (e.g., maximum voluntary contraction) in untrained children and adolescents. Effects of plyometric training in untrained youth primarily follow the principle of training specificity. Despite the fact that only 6 out of 75 comparative studies investigated resistance or plyometric training in trained individuals, positive effects were reported in all 6 studies (e.g., maximum strength and vertical jump height, respectively). Conclusions The present review article identified research gaps (e.g., training descriptors, modern alternative training modalities) that should be addressed in future comparative studies.}, language = {en} } @article{MuehlbauerBesemerWehrleetal.2012, author = {M{\"u}hlbauer, Thomas and Besemer, Carmen and Wehrle, Anja and Gollhofer, Albert and Granacher, Urs}, title = {Relationship between strength, power and balance performance in seniors}, series = {Gerontology}, volume = {58}, journal = {Gerontology}, number = {6}, publisher = {Karger}, address = {Basel}, issn = {0304-324X}, doi = {10.1159/000341614}, pages = {504 -- 512}, year = {2012}, abstract = {Background: Deficits in strength, power and balance represent important intrinsic risk factors for falls in seniors. Objective: The purpose of this study was to investigate the relationship between variables of lower extremity muscle strength/power and balance, assessed under various task conditions. Methods: Twenty-four healthy and physically active older adults (mean age: 70 8 5 years) were tested for their isometric strength (i.e. maximal isometric force of the leg extensors) and muscle power (i.e. countermovement jump height and power) as well as for their steady-state (i.e. unperturbed standing, 10-meter walk), proactive (i.e. Timed Up \& Go test, Functional Reach Test) and reactive (i.e. perturbed standing) balance. Balance tests were conducted under single (i.e. standing or walking alone) and dual task conditions (i.e. standing or walking plus cognitive and motor interference task). Results: Significant positive correlations were found between measures of isometric strength and muscle power of the lower extremities (r values ranged between 0.608 and 0.720, p < 0.01). Hardly any significant associations were found between variables of strength, power and balance (i.e. no significant association in 20 out of 21 cases). Additionally, no significant correlations were found between measures of steady-state, proactive and reactive balance or balance tests performed under single and dual task conditions (all p > 0.05). Conclusion: The predominately nonsignificant correlations between different types of balance imply that balance performance is task specific in healthy and physically active seniors. Further, strength, power and balance as well as balance under single and dual task conditions seem to be independent of each other and may have to be tested and trained complementarily.}, language = {en} } @article{GrabowYoungAlcocketal.2018, author = {Grabow, Lena and Young, James D. and Alcock, Lynsey R. and Quigley, Patrick J. and Byrne, Jeannette M. and Granacher, Urs and Skarabot, Jakob and Behm, David George}, title = {Higher Quadriceps Roller Massage Forces Do Not Amplify Range-of-Motion Increases nor Impair Strength and Jump Performance}, series = {Journal of strength and conditioning research : the research journal of the NSCA}, volume = {32}, journal = {Journal of strength and conditioning research : the research journal of the NSCA}, number = {11}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia}, issn = {1064-8011}, doi = {10.1519/JSC.0000000000001906}, pages = {3059 -- 3069}, year = {2018}, abstract = {Grabow, L, Young, JD, Alcock, LR, Quigley, PJ, Byrne, JM, Granacher, U, Škarabot, J, and Behm, DG. Higher quadriceps roller massage forces do not amplify range-of-motion increases nor impair strength and jump performance. J Strength Cond Res 32(11): 3059-3069, 2018—Roller massage (RM) has been reported to increase range of motion (ROM) without subsequent performance decrements. However, the effects of different rolling forces have not been examined. The purpose of this study was to compare the effects of sham (RMsham), moderate (RMmod), and high (RMhigh) RM forces, calculated relative to the individuals' pain perception, on ROM, strength, and jump parameters. Sixteen healthy individuals (27 ± 4 years) participated in this study. The intervention involved three 60-second quadriceps RM bouts with RMlow (3.9/10 ± 0.64 rating of perceived pain [RPP]), RMmod (6.2/10 ± 0.64 RPP), and RMhigh (8.2/10 ± 0.44 RPP) pain conditions, respectively. A within-subject design was used to assess dependent variables (active and passive knee flexion ROM, single-leg drop jump [DJ] height, DJ contact time, DJ performance index, maximum voluntary isometric contraction [MVIC] force, and force produced in the first 200 milliseconds [F200] of the knee extensors and flexors). A 2-way repeated measures analysis of variance showed a main effect of testing time in active (p < 0.001, d = 2.54) and passive (p < 0.001, d = 3.22) ROM. Independent of the RM forces, active and passive ROM increased by 7.0\% (p = 0.03, d = 2.25) and 15.4\% (p < 0.001, d = 3.73) from premeasure to postmeasure, respectively. Drop jump and MVIC parameters were unaffected from pretest to posttest (p > 0.05, d = 0.33-0.84). Roller massage can be efficiently used to increase ROM without substantial pain and without subsequent performance impairments.}, language = {en} } @article{PrieskeChaabeneGaebleretal.2020, author = {Prieske, Olaf and Chaabene, Helmi and G{\"a}bler, Martijn and Herz, Michael and Helm, Norman and Markov, Adrian and Granacher, Urs}, title = {Seasonal changes in anthropometry, body composition, and physical fitness and the relationships with sporting success in young sub-elite judo athletes}, series = {International journal of environmental research and public health : IJERPH}, volume = {17}, journal = {International journal of environmental research and public health : IJERPH}, number = {19}, publisher = {MDPI AG}, address = {Basel}, issn = {1660-4601}, doi = {10.3390/ijerph17197169}, pages = {17}, year = {2020}, abstract = {This exploratory study aimed to monitor long-term seasonal developments in measures of anthropometry, body composition, and physical fitness in young judo athletes, and to compute associations between these measures and sporting success. Forty-four young judoka (20 females, 24 males) volunteered to participate. Tests for the assessment of anthropometry (e.g., body height/mass), body-composition (e.g., lean body mass), muscle strength (isometric handgrip strength), vertical jumping (e.g., countermovement-jump (CMJ) height), and dynamic balance (Y-balance test) were conducted at the beginning and end of a 10-month training season. Additionally, sporting success at the end of the season was recorded for each athlete. Analyses revealed significant time x sex interaction effects for lean-body-mass, isometric handgrip strength, and CMJ height (0.7 <= d <= 1.6). Post-hoc analyses showed larger gains for all measures in young males (1.9 <= d <= 6.0) compared with females (d = 2.4) across the season. Additionally, significant increases in body height and mass as well as Y-balance test scores were found from pre-to-post-test (1.2 <= d <= 4.3), irrespective of sex. Further, non-significant small-to-moderate-sized correlations were identified between changes in anthropometry/body composition/physical fitness and sporting success (p > 0.05; -0.34 <= rho <= 0.32). Regression analysis confirmed that no model significantly predicted sporting success. Ten months of judo training and/or growth/maturation contributed to significant changes in anthropometry, body composition, and physical fitness, particularly in young male judo athletes.}, language = {en} } @article{GranacherPrieskeMajewskietal.2015, author = {Granacher, Urs and Prieske, Olaf and Majewski, M. and B{\"u}sch, Dirk and M{\"u}hlbauer, Thomas}, title = {The Role of Instability with Plyometric Training in Sub-elite Adolescent Soccer Players}, series = {International journal of sports medicine}, volume = {36}, journal = {International journal of sports medicine}, number = {5}, publisher = {Thieme}, address = {Stuttgart}, issn = {0172-4622}, doi = {10.1055/s-0034-1395519}, pages = {386 -- 394}, year = {2015}, abstract = {The purpose of this study was to investigate the effects of plyometric training on stable (SPT) vs. highly unstable surfaces (IPT) on athletic performance in adolescent soccer players. 24 male sub-elite soccer players (age: 15 +/- 1 years) were assigned to 2 groups performing plyometric training for 8 weeks (2 sessions/week, 90min each). The SPT group conducted plyometrics on stable and the IPT group on unstable surfaces. Tests included jump performance (countermovement jump [CMJ] height, drop jump [DJ] height, DJ performance index), sprint time, agility and balance. Statistical analysis revealed significant main effects of time for CMJ height (p<0.01, f=1.44), DJ height (p<0.01, f=0.62), DJ performance index (p<0.05, f=0.60), 0-10-m sprint time (p<0.05, f=0.58), agility (p<0.01, f=1.15) and balance (p<0.05, 0.46f1.36). Additionally, a Training groupxTime interaction was found for CMJ height (p<0.01, f=0.66) in favor of the SPT group. Following 8 weeks of training, similar improvements in speed, agility and balance were observed in the IPT and SPT groups. However, the performance of IPT appears to be less effective for increasing CMJ height compared to SPT. It is thus recommended that coaches use SPT if the goal is to improve jump performance.}, language = {en} } @article{MuehlbauerStuerchlerGranacher2012, author = {M{\"u}hlbauer, Thomas and St{\"u}rchler, M. and Granacher, Urs}, title = {Effects of climbing on core strength and mobility in adults}, series = {International journal of sports medicine}, volume = {33}, journal = {International journal of sports medicine}, number = {6}, publisher = {Thieme}, address = {Stuttgart}, issn = {0172-4622}, doi = {10.1055/s-0031-1301312}, pages = {445 -- 451}, year = {2012}, abstract = {The objective of this study was to examine the impact of an indoor climbing training and detraining program on core/handgrip strength and trunk mobility in men and women. 28 young sedentary adults participated in this study and were assigned to an intervention (30+/-3 years) or a control (29+/-2 years) group. The intervention group participated in 8 weeks (2 times/week) of indoor climbing training, followed by 8 weeks of detraining. Tests included the measurement of maximal isometric strength (MIS) of the trunk flexors/extensors, the assessment of trunk mobility in the sagittal (SAP) and the coronal (CRP) plane as well as testing of handgrip strength. After training, significant improvements were observed in MIS of the trunk flexors/extensors (similar to 19-22 \%, all p<0.01), in trunk mobility in SAP/CRP (similar to 14-19 \%, all p<0.01), and in handgrip strength (similar to 5 \%, p<0.01). During detraining, MIS (similar to 12-13 \%, all p<0.01) and trunk mobility (similar to 7-10\%, all p<0.01) deteriorated significantly, whereas handgrip strength remained. This indoor climbing training program conducted in sedentary adults proved to be feasible (i.e., attendance rate of 89.4\%) and effective. It is suggested that indoor climbing should be permanently conducted to maintain the observed improvements in core muscle strength and trunk mobility.}, language = {en} } @article{MuehlbauerGollhoferGranacher2012, author = {M{\"u}hlbauer, Thomas and Gollhofer, Albert and Granacher, Urs}, title = {Sex-related effects in strength training during adolescence a pilot study}, series = {Perceptual \& motor skills}, volume = {115}, journal = {Perceptual \& motor skills}, number = {3}, publisher = {Sage Publ.}, address = {Missoula}, issn = {0031-5125}, doi = {10.2466/06.10.30.PMS.115.6.953-968}, pages = {953 -- 968}, year = {2012}, abstract = {The objective was to investigate the effects of high-velocity strength training on isometric strength of the leg extensors and jump height in female and male adolescents. Twenty-eight students (13 boys, 15 girls) ages 16 to 17 years participated in this study and were assigned to either a strength training group or a control group. Strength training was conducted over 8 weeks (2 times per week). Pre- and post-training tests included the measurements of maximal isometric force and rate of force development of the leg extensors as well as countermovement jump height. Both girls (effect size = 1.37) and boys (effect size = 0.61) showed significant improvements in jump height. However, significant increases in maximal isometric force (effect size = 1.85) and rate of force development (effect size = 2.23) were found only in girls. In female and male adolescents, high-velocity strength training is an effective training regimen that produced improvements in countermovement jump height in both sexes but higher gains in maximal isometric force and rate of force development in girls.}, language = {en} } @article{MuehlbauerKuehnenGranacher2013, author = {M{\"u}hlbauer, Thomas and K{\"u}hnen, Matthias and Granacher, Urs}, title = {Inline skating for balance and strength promotion in children during physical education}, series = {Perceptual \& motor skills}, volume = {117}, journal = {Perceptual \& motor skills}, number = {3}, publisher = {Sage Publ.}, address = {Missoula}, issn = {0031-5125}, doi = {10.2466/30.06.PMS.117x29z9}, pages = {665 -- 681}, year = {2013}, abstract = {Deficiencies in balance and strength are common in children and they may lead to injuries. This study investigated the effects of inline skating exercise on balance and strength performance in healthy children. Twenty 11-12-year-old children (8 girls, 12 boys) were assigned to an intervention (n = 10) or a control (n = 10) group. Participants in the intervention group underwent a 4-week inline skating program (2 times/week, 90 min. each) integrated in their physical education lessons. Balance and strength were measured using the Star Excursion Balance test and the countermovement jump test. As compared to the control group, the intervention group significantly improved balance (17-48\%, Cohen's d = 0.00-1.49) and jump height (8\%, Cohen's d = 0.48). In children, inline skating is a safe, feasible (90\% adherence rate), and effective program that can be integrated in physical education lessons to promote balance and strength.}, language = {en} } @article{ChaabenePrieskeNegraetal.2018, author = {Chaabene, Helmi and Prieske, Olaf and Negra, Yassine and Granacher, Urs}, title = {Change of direction speed}, series = {Sports medicine}, volume = {48}, journal = {Sports medicine}, number = {8}, publisher = {Springer}, address = {Northcote}, issn = {0112-1642}, doi = {10.1007/s40279-018-0907-3}, pages = {1773 -- 1779}, year = {2018}, abstract = {There is growing evidence that eccentric strength training appears to have benefits over traditional strength training (i.e., strength training with combined concentric and eccentric muscle actions) from muscular, neuromuscular, tendinous, and metabolic perspectives. Eccentric muscle strength is particularly needed to decelerate and stabilize the body during the braking phase of a jump exercise or during rapid changes of direction (CoD) tasks. However, surprisingly little research has been conducted to elucidate the effects of eccentric strength training or strength training with accentuated eccentric muscle actions on CoD speed performance. In this current opinion article, we present findings from cross-sectional studies on the relationship between measures of eccentric muscle strength and CoD speed performance. In addition, we summarize the few available studies on the effects of strength training with accentuated eccentric muscle actions on CoD speed performance in athletic populations. Finally, we propose strength training with accentuated eccentric muscle actions as a promising element in strength and conditioning programs of sports with high CoD speed demands. Our findings from five cross-sectional studies revealed statistically significant moderate-to large-sized correlations (r = 0.45-0.89) between measures of eccentric muscle strength and CoD speed performance in athletic populations. The identified three intervention studies were of limited methodological quality and reported small-to large-sized effects (d = 0.46-1.31) of strength training with accentuated eccentric muscle actions on CoD speed performance in athletes. With reference to the available but preliminary literature and from a performance-related point of view, we recommend strength and conditioning coaches to include strength training with accentuated eccentric muscle actions in training routines of sports with high CoD speed demands (e.g., soccer, handball, basketball, hockey) to enhance sport-specific performance. Future comparative studies are needed to deepen our knowledge of the effects of strength training with accentuated eccentric muscle actions on CoD speed performance in athletes.}, language = {en} } @article{HelmPrieskeMuehlbaueretal.2020, author = {Helm, Norman and Prieske, Olaf and M{\"u}hlbauer, Thomas and Kr{\"u}ger, Tom and Retzlaff, Matthias and Granacher, Urs}, title = {Associations between trunk muscle strength and judo-specific pulling performances in judo athletes}, series = {Sportverletzung, Sportschaden : Grundlagen, Pr{\"a}vention, Rehabilitation}, volume = {34}, journal = {Sportverletzung, Sportschaden : Grundlagen, Pr{\"a}vention, Rehabilitation}, number = {1}, publisher = {Thieme}, address = {Stuttgart}, issn = {0932-0555}, doi = {10.1055/a-0677-9608}, pages = {18 -- 27}, year = {2020}, abstract = {Background: Good trunk stability is an important prerequisite for the mobility of the upper and lower limbs during sport-specific movements. Therefore, trunk muscle strength may represent an important performance determinant for judo-specific movements. This study aimed at evaluating statistical correlations between trunk muscle strength and kinetic parameters during judo-specific pulling movements in judo players. Method: Twenty-one male sub-elite judo players aged 22 +/- 4 years with a mean training volume of 15 +/- 4 hours per week participated in this study. Peak isokinetic torque (PIT) of the trunk flexors (PITFlex), extensors (PITEx) and rotators (PITRot) was tested using an isokinetic dynamometer (IsoMed 2000). In addition, two kinetic parameters (mechanical work [W], maximal force [F-max]) were analysed using the judo-specific measurement and information system JERGo (c). For this purpose, athletes were asked to do their judo-specific pulling movements while standing and with a dynamic change of position (i.e. Morote-seoi-nage). Results: Regarding pulling movements while standing, significant correlations (0.62 <= r(P) <= 0.72) were found between isokinetic tests (PITFlex, PITEx, PITRot) and mechanical work during judo-specific movement. Further, significant correlations (0.59 <= r(P) <= 0.65) were detected between isokinetic tests (PITEx, PITRot) and judo-specific pulling movements (Fmax). Regarding pulling movements with a change of position, significant correlations (0.47 <= r(P) <= 0.88) were observed between isokinetics (PITFlex, PITEx, PITRot) and the kinetic pulling parameters (W, Fmax), irrespective of the examined arm. No significant differences in magnitude of correlation coefficients were found between PIT of the trunk flexors, extensors, and rotators and judo-specific movements. Further, the regression analysis indicated that PIT of the trunk extensors is the single best predictor for mechanical work during pulling movements while standing (46.9 \%). Trunk rotator PIT is the single best predictor for mechanical work during pulling movements with a change of position (69.4 \%). Conclusions: Findings from this study indicate that trunk muscle strength, particularly trunk rotator PIT is associated with kinetic pulling variables during pulling movements with a change of position. This implies that the development of trunk rotator strength could have an impact on pulling movements with a change of position (i.e. Morote-seoi-nage) in judo athletes.}, language = {de} } @misc{MoranRamirezCampilloGranacher2018, author = {Moran, Jason and Ramirez-Campillo, Rodrigo and Granacher, Urs}, title = {Effects of Jumping Exercise on Muscular Power in Older Adults}, series = {Sports medicine}, volume = {48}, journal = {Sports medicine}, number = {12}, publisher = {Springer}, address = {Northcote}, issn = {0112-1642}, doi = {10.1007/s40279-018-1002-5}, pages = {2843 -- 2857}, year = {2018}, abstract = {Background Jump training (JT) can be used to enhance the ability of skeletal muscle to exert maximal force in as short a time as possible. Despite its usefulness as a method of performance enhancement in athletes, only a small number of studies have investigated its effects on muscle power in older adults. Objectives The aims of this meta-analysis were to measure the effect of JT on muscular power in older adults (≥ 50 years), and to establish appropriate programming guidelines for this population. Data Sources The data sources utilised were Google Scholar, PubMed, and Microsoft Academic. Study Eligibility Criteria Studies were eligible for inclusion if they comprised JT interventions in healthy adults (≥ 50 years) who were free of any medical condition that could impair movement. Study Appraisal and Synthesis Methods The inverse variance random-effects model for meta-analyses was used because it allocates a proportionate weight to trials based on the size of their individual standard errors and facilitates analysis while accounting for heterogeneity across studies. Effect sizes (ESs), calculated from a measure of muscular power, were represented by the standardised mean difference and were presented alongside 95\% confidence intervals (CIs). Results Thirteen training groups across nine studies were included in this meta-analysis. The magnitude of the main effect was 'moderate' (0.66, 95\% CI 0.33, 0.98). ESs were larger in non-obese participants (body mass index [BMI] < 30 vs. ≥ 30 kg/m2; 1.03 [95\% CI 0.34, 1.73] vs. 0.53 [95\% CI - 0.03, 1.09]). Among the studies included in this review, just one reported an acute injury, which did not result in the participant ceasing their involvement. JT was more effective in programmes with more than one exercise (range 1-4 exercises; ES = 0.74 [95\% CI - 0.49, 1.96] vs. 0.53 [95\% CI 0.29, 0.78]), more than two sets per exercise (range 1-4 sets; ES = 0.91 [95\% CI 0.04, 1.77] vs. 0.68 [95\% CI 0.15, 1.21]), more than three jumps per set (range 1-14 jumps; ES = 1.02 [95\% CI 0.16, 1.87] vs. 0.53 [95\% CI - 0.03, 1.09]) and more than 25 jumps per session (range 6-200 jumps; ES = 0.88 [95\% CI 0.05, 1.70] vs. 0.49 [95\% CI 0.14, 0.83]). Conclusions JT is safe and effective in older adults. Practitioners should construct varied JT programmes that include more than one exercise and comprise more than two sets per exercise, more than three jumps per set, and 60 s of recovery between sets. An upper limit of three sets per exercise and ten jumps per set is recommended. Up to three training sessions per week can be performed.}, language = {en} } @article{ChaabeneLesinskiBehmetal.2020, author = {Chaabene, Helmi and Lesinski, Melanie and Behm, David George and Granacher, Urs}, title = {Performance- and healthrelated benefits of youth resistance training}, series = {Sports Orthopaedics and Traumatology}, volume = {36}, journal = {Sports Orthopaedics and Traumatology}, number = {3}, publisher = {Elsevier}, address = {Amsterdam}, pages = {10}, year = {2020}, abstract = {Performance- and healthrelated benefits of yoThere is ample evidence that youth resistance training (RT) is safe, joyful, and effective for different markers of performance (e.g., muscle strength, power, linear sprint speed) and health (e.g., injury prevention). Accordingly, the first aim of this narrative review is to present and discuss the relevance of muscle strength for youth physical development. The second purpose is to report evidence on the effectiveness of RT on muscular fitness (muscle strength, power, muscle endurance), on movement skill performance and injury prevention in youth. There is evidence that RT is effective in enhancing measures of muscle fitness in children and adolescents, irrespective of sex. Additionally, numerous studies indicate that RT has positive effects on fundamental movement skills (e.g., jumping, running, throwing) in youth regardless of age, maturity, training status, and sex. Further, irrespective of age, sex, and training status, regular exposure to RT (e.g., plyometric training) decreases the risk of sustaining injuries in youth. This implies that RT should be a meaningful element of youths' exercise programming. This has been acknowledged by global (e.g., World Health Organization) and national (e.g., National Strength and Conditioning Association) health- and performance-related organizations which is why they recommended to perform RT as an integral part of weekly exercise programs to promote muscular strength, fundamental movement skills, and to resist injuries in youth.uth resistance training}, language = {en} } @article{GranacherGruberGollhofer2009, author = {Granacher, Urs and Gruber, Markus and Gollhofer, Albert}, title = {Resistance training and neuromuscular performance in seniors}, issn = {0172-4622}, doi = {10.1055/s-0029-1224178}, year = {2009}, abstract = {Age-related processes in the neuromuscular and the somatosensory system are responsible for decreases in maximal and explosive force production capacity and deficits in postural control. Thus, the objectives of this study were to investigate the effects of resistance training on strength performance and on postural control in seniors. Forty healthy seniors (67 +/- 1 yrs) participated in this study. Subjects were randomly assigned to a resistance training (n = 20) and a control group (n = 20). Resistance training for the lower extremities lasted for 13 weeks at 80\% of the one repetition maximum. Pre and post tests included the measurement of maximal isometric leg extension force with special emphasis on the early part of the force-time-curve and the assessment of static (functional reach test) and dynamic (tandem walk test, platform perturbation) postural control. Resistance training resulted I in an enhanced strength performance with increases I in explosive force exceeding those in maximal strength. Improved performances in the functional reach and in the tandem walk test were observed. Resistance training did not have an effect: on the compensation of platform perturbations. Increases in strength performance can primarily be explained by an improved neural drive of the agonist muscles. The inconsistent effect of resistance training on postural control may be explained by heterogeneity of testing methodology or by the incapability of isolated resisiance training to improve postural control.}, language = {en} } @article{HaileFuehnerGranacheretal.2021, author = {Haile, Sarah R. and F{\"u}hner, Thea Heidi and Granacher, Urs and Stocker, Julien and Radtke, Thomas and Kriemler, Susi}, title = {Reference values and validation of the 1-minute sit-to-stand test in healthy 5-16-year-old youth}, series = {BMJ open}, volume = {11}, journal = {BMJ open}, number = {5}, publisher = {BMJ Publishing Group}, address = {London}, issn = {2044-6055}, doi = {10.1136/bmjopen-2021-049143}, pages = {7}, year = {2021}, abstract = {Objectives: It is essential to have simple, reliable and valid tests to measure children's functional capacity in schools or medical practice. The 1-minute sit-to-stand (STS) test is a quick fitness test requiring little equipment or space that is increasingly used in both healthy populations and those with chronic disease. We aimed to provide age-specific and sex-specific reference values of STS test in healthy children and adolescents and to evaluate its short-term reliability and construct validity. Design setting and participants: Cross-sectional convenience sample from six public schools and one science fair in central Europe. Overall, 587 healthy participants aged 5-16 years were recruited and divided into age groups of 3 years each. Outcomes: 1-minute STS. To evaluate short-term reliability, some children performed the STS test twice. To evaluate construct validity, some children also performed a standing long jump (SLJ) and a maximal incremental exercise test. Results: Data from 547 youth aged 5-16 years were finally included in the analyses. The median number of repetitions in 1 min in males (females) ranged from 55 [95\% CI: 38 to 72] (53 [95\% CI: 35 to 76]) in 14-16-year olds to 59 [95\% CI: 41 to 77] (60 [95\% CI: 38 to 77]) in 8-10-year olds. Children who repeated STS showed a learning effect of on average 4.8 repetitions more than the first test (95\% limits of agreement: -6.7 to 16.4). Moderate correlations were observed between the STS and the SLJ (r=0.48) tests and the maximal exercise test (r=0.43). Conclusions: The reported STS reference values can be used to interpret STS test performance in children and adolescents. The STS appears to have good test- retest reliability, but a learning effect of about 10\%. The association of STS with other measures of physical fitness should be further explored in a larger study and technical standards for its conduct are needed.}, language = {en} } @article{JafarnezhadgeroGhorbanlooFatollahietal.2021, author = {Jafarnezhadgero, AmirAli and Ghorbanloo, Farshad and Fatollahi, Amir and Dionisio, Valdeci Carlos and Granacher, Urs}, title = {Effects of an elastic resistance band exercise program on kinetics and muscle activities during walking in young adults with genu valgus}, series = {Clinical biomechanics : a journal affiliated to the International Society of Biomechanics and the American Society of Biomechanics}, volume = {81}, journal = {Clinical biomechanics : a journal affiliated to the International Society of Biomechanics and the American Society of Biomechanics}, publisher = {Elsevier Science}, address = {Amsterdam [u.a.]}, issn = {0268-0033}, doi = {10.1016/j.clinbiomech.2020.105215}, pages = {10}, year = {2021}, abstract = {Background: This double-blinded randomized-controlled-trial aimed to identify the effects of an elastic band resistance training on walking kinetics and muscle activities in young adults with genu valgus. Methods: Forty-two male young adults aged 22.5(2.7) years with genu valgus were randomly allocated to two experimental groups. The intervention group (n = 21) conducted a 14-weeks elastic band resistance training. The control group was passive during the intervention period and received the same treatment after the post-tests. Pre and post training, ground reaction forces and lower limb muscle activities were recorded during walking. Findings: Results revealed significant group-by-time interactions for peak medial ground reaction force and timeto-peak for posterior ground reaction force in favor of the intervention group (p < 0.012; d = 0.83-3.76). Resistance training with elastic bands resulted in significantly larger peak medial ground reaction force (p < 0.001; d = 1.45) and longer time-to-peak for posterior ground reaction force (p < 0.001; d = 1.85). Finding showed significant group-by-time interactions for peak positive free moment amplitudes in favor of the intervention group (p < 0.001; d = 1.18-2.02). Resistance training resulted in a lower peak positive free moment amplitude (p = 0.001; d = 1.46). With regards to muscle activities, the analysis revealed significant group-by time interactions for rectus femoris and gluteus medius activities during the push-off phase in favor of the intervention group (p < 0.038; d = 0.68-0.89). Resistance training induced higher rectus femoris (p = 0.038; d = 0.84) and gluteus medius (p = 0.007; d = 0.54) activities. Interpretation: This study proved the effectiveness of resistance training using elastic bands on kinetics and muscle activities during walking in male adults with genu valgus disorder. Given that this training regime is low cost, effective, and easy-to-administer, we suggest that it should be implemented as a rehabilitative or preventive means for young adults with genu valgus.}, language = {en} } @article{WickKriemlerGranacher2021, author = {Wick, Kristin and Kriemler, Susi and Granacher, Urs}, title = {Effects of a strength-dominated exercise program on physical fitness and cognitive performance in preschool children}, series = {Journal of strength and conditioning research : the research journal of the NSCA}, volume = {35}, journal = {Journal of strength and conditioning research : the research journal of the NSCA}, number = {4}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia}, issn = {1064-8011}, doi = {10.1519/JSC.0000000000003942}, pages = {983 -- 990}, year = {2021}, abstract = {Wick, K, Kriemler, S, and Granacher, U. Effects of a strength-dominated exercise program on physical fitness and cognitive performance in preschool children. J Strength Cond Res 35(4): 983-990, 2021-Childhood is characterized by high neuroplasticity that affords qualitative rather than quantitative components of physical activity to maximize the potential to sufficiently develop motor skills and foster long-term engagement in regular physical activity. This study examined the effects of an integrative strength-dominated exercise program on measures of physical fitness and cognitive performance in preschool children. Children aged 4-6 years from 3 kindergartens were randomized into an intervention (INT) group (n = 32) or a control group (n = 22). The 10-week intervention period was conducted 3 times per week (each session lasted 30 minutes) and included exercises for the promotion of muscle strength and power, coordination, and balance. Pre and post training, tests were conducted for the assessment of muscle strength (i.e., handgrip strength), muscle power (i.e., standing long jump), balance (i.e., timed single-leg stand), coordination (hopping on right/left leg), and attentional span (i.e., "Konzentrations-Handlungsverfahren fur Vorschulkinder" [concentration-action procedure for preschoolers]). Results from 2 x 2 repeated-measures analysis of covariance revealed a significant (p <= 0.05) and near significant (p = 0.051) group x time interaction for the standing long jump test and the Konzentrations-Handlungsverfahren. Post hoc tests showed significant pre-post changes for the INT (p < 0.001; d = 1.53) but not the CON (p = 0.72; d = 0.83). Our results indicate that a 10-week strength-dominated exercise program increased jump performance with a concomitant trend toward improvements in attentional capacity of preschool children. Thus, we recommend implementing this type of exercise program for preschoolers.}, language = {en} } @article{ChaouachiGranacherMakhloufetal.2017, author = {Chaouachi, Mehdi and Granacher, Urs and Makhlouf, Issam and Hammami, Raouf and Behm, David G. and Chaouachi, Anis}, title = {Within Session Sequence of Balance and Plyometric Exercises Does Not Affect Training Adaptations with Youth Soccer Athletes}, series = {Journal of sports science \& medicine}, volume = {16}, journal = {Journal of sports science \& medicine}, publisher = {Department of Sports Medicine, Medical Faculty of Uludag University}, address = {Bursa}, issn = {1303-2968}, pages = {125 -- 136}, year = {2017}, abstract = {The integration of balance and plyometric training has been shown to provide significant improvements in sprint, jump, agility, and other performance measures in young athletes. It is not known if a specific within session balance and plyometric exercise sequence provides more effective training adaptations. The objective of the present study was to investigate the effects of using a sequence of alternating pairs of exercises versus a block (series) of all balance exercises followed by a block of plyometric exercises on components of physical fitness such as muscle strength, power, speed, agility, and balance. Twenty-six male adolescent soccer players ( 13.9 +/- 0.3 years) participated in an 8-week training program that either alternated individual balance (e. g., exercises on unstable surfaces) and plyometric (e. g., jumps, hops, rebounds) exercises or performed a block of balance exercises prior to a block of plyometric exercises within each training session. Pre- and post-training measures included proxies of strength, power, agility, sprint, and balance such as countermovement jumps, isometric back and knee extension strength, standing long jump, 10 and 30-m sprints, agility, standing stork, and Y-balance tests. Both groups exhibited significant, generally large magnitude (effect sizes) training improvements for all measures with mean performance increases of approximately > 30\%. There were no significant differences between the training groups over time. The results demonstrate the effectiveness of combining balance and plyometric exercises within a training session on components of physical fitness with young adolescents. The improved performance outcomes were not significantly influenced by the within session exercise sequence.}, language = {en} } @book{MuehlbauerRothKibeleetal.2013, author = {M{\"u}hlbauer, Thomas and Roth, Ralf and Kibele, Armin and Behm, David George and Granacher, Urs}, title = {Krafttraining mit Kindern und Jugendlichen}, series = {Praxisideen}, journal = {Praxisideen}, number = {58}, editor = {Kr{\"o}ger, Christian and Roth, Klaus and Haag, Herbert}, publisher = {Hofmann}, address = {Schorndorf}, isbn = {978-3-7780-2581-9}, pages = {192}, year = {2013}, abstract = {Dieser Band besch{\"a}ftigt sich mit den theoretischen Grundlagen und der praktischen Umsetzung von Krafttraining mit Kindern und Jugendlichen. Ausgehend von der Kennzeichnung der k{\"o}rperlichen Situation und der Kraftentwicklung im Kindes- und Jugendalter werden die Effekte von Krafttraining bei Kindern und Jugendlichen aufgezeigt. Hierzu z{\"a}hlen neben Verbesserungen der Kraftausdauer, der Maximal- und Schnellkraft, die F{\"o}rderung elementarer und sportartspezifischer Fertigkeiten sowie die g{\"u}nstige Beeinflussung gesundheitsrelevanter Faktoren (u.a. Verletzungsh{\"a}ufigkeit, Knochenstatus, kardio-vaskul{\"a}re und psycho-soziale Kennwerte). Im Anschluss werden neuronale und muskul{\"a}re Mechanismen zur Erkl{\"a}rung der trainingsbedingten Anpassungen beschrieben. Das Kernst{\"u}ck des Buches bildet die Darstellung und Beschreibung vielf{\"a}ltiger {\"U}bungsbeispiele f{\"u}r ein Krafttraining an Maschinen, mit Freihanteln, Zusatzger{\"a}ten, dem eigenen K{\"o}rpergewicht und ein Sprungkrafttraining. Hierbei wurden insbesondere {\"U}bungen ausgew{\"a}hlt, die sich f{\"u}r den Einsatz im Schul- und Vereinssport eignen. Dieses Buch dient somit Lehrern, {\"U}bungsleitern und Trainern, ein zielgerichtetes Krafttraining mit Kindern und Jugendlichen wirkungsvoll und sicher durchzuf{\"u}hren.}, language = {de} } @article{PrieskeAboodardaSierraetal.2017, author = {Prieske, Olaf and Aboodarda, Saied J. and Sierra, Jose A. Benitez and Behm, David G. and Granacher, Urs}, title = {Slower but not faster unilateral fatiguing knee extensions alter contralateral limb performance without impairment of maximal torque output}, series = {European journal of applied physiology}, volume = {117}, journal = {European journal of applied physiology}, publisher = {Springer}, address = {New York}, issn = {1439-6319}, doi = {10.1007/s00421-016-3524-6}, pages = {323 -- 334}, year = {2017}, abstract = {The purpose of the present study was to examine the effects of unilateral fatigue of the knee extensors at different movement velocities on neuromuscular performance in the fatigued and non-fatigued leg. Unilateral fatigue of the knee extensors was induced in 11 healthy young men (23.7 +/- 3.8 years) at slower (60A degrees/s; FAT60) and faster movement velocities (240A degrees/s; FAT240) using an isokinetic dynamometer. A resting control (CON) condition was included. The fatigue protocols consisted of five sets of 15 maximal concentric knee extensions using the dominant leg. Before and after fatigue, peak isokinetic torque (PIT) and time to PIT (TTP) of the knee extensors as well as electromyographic (EMG) activity of vastus medialis, vastus lateralis, and biceps femoris muscles were assessed at 60 and 240A degrees/s movement velocities in the fatigued and non-fatigued leg. In the fatigued leg, significantly greater PIT decrements were observed following FAT60 and FAT240 (11-19\%) compared to CON (3-4\%, p = .002, d = 2.3). Further, EMG activity increased in vastus lateralis and biceps femoris muscle following FAT240 only (8-28\%, 0.018 <= p <=.024, d = 1.8). In the non-fatigued leg, shorter TTP values were found after the FAT60 protocol (11-15\%, p = .023, d = 2.4). No significant changes were found for EMG data in the non-fatigued leg. The present study revealed that both slower and faster velocity fatiguing contractions failed to show any evidence of cross-over fatigue on PIT. However, unilateral knee extensor fatigue protocols conducted at slower movement velocities (i.e., 60A degrees/s) appear to modulate torque production on the non-fatigued side (evident in shorter TTP values).}, language = {en} } @article{JafarnezhadgeroFatollahiGranacher2022, author = {Jafarnezhadgero, Amir Ali and Fatollahi, Amir and Granacher, Urs}, title = {Eight weeks of exercising on sand has positive effects on biomechanics of walking and muscle activities in individuals with pronated feet}, series = {Sports : open access journal}, volume = {10}, journal = {Sports : open access journal}, number = {5}, publisher = {MDPI}, address = {Basel}, issn = {2075-4663}, doi = {10.3390/sports10050070}, pages = {16}, year = {2022}, abstract = {This study aimed to investigate the effects of eight weeks of barefoot running exercise on sand versus control on measures of walking kinetics and muscle activities in individuals with diagnosed pronated feet. Sixty physically active male adults with pronated feet were randomly allocated into an intervention or a waiting control group. The intervention group conducted an 8-weeks progressive barefoot running exercise program on sand (e.g., short sprints) with three weekly sessions. Pre and post intervention, participants walked at a constant speed of 1.3 m/s +/- 5\% on a 18 m walkway with a force plate embedded in the middle of the walkway. Results showed significant group-by-time interactions for peak impact vertical and lateral ground reaction forces. Training but not control resulted in significantly lower peak impact vertical and lateral ground reaction forces. Significant group-by-time interactions were observed for vastus lateralis activity during the loading phase. Training-induced increases were found for the vastus lateralis in the intervention but not in the control group. This study revealed that the applied exercise program is a suitable means to absorb ground reaction forces (e.g., lower impact vertical and lateral peaks) and increase activities of selected lower limb muscles (e.g., vastus lateralis) when walking on stable ground.}, language = {en} } @article{NegraChaabeneSammoudetal.2017, author = {Negra, Yassine and Chaabene, Helmi and Sammoud, Senda and Bouguezzi, Raja and Abbes, Mohamed Aymen and Hachana, Younes and Granacher, Urs}, title = {Effects of Plyometric Training on Physical Fitness in Prepuberal Soccer Athletes}, series = {International journal of sports medicine}, volume = {38}, journal = {International journal of sports medicine}, publisher = {Thieme}, address = {Stuttgart}, issn = {0172-4622}, doi = {10.1055/s-0042-122337}, pages = {370 -- 377}, year = {2017}, abstract = {This study aimed at examining the effects of plyometric training on stable (SPT) vs. unstable (UPT) surfaces on physical fitness in prepuberal soccer players. Male athletes were randomly assigned to SPT (n = 18; age = 12.7 +/- 0.2 years) or UPT (n = 16; age = 12.2 +/- 0.5 years). Both groups conducted 3 regular soccer training sessions per week combined with either 2 SPT or UPT sessions. Assessment of jumping ability (countermovement jump [CMJ], and standing long jump [SLJ]), speed (10-m, 20-m, 30-m sprint), agility (Illinois agility test [IAT]), and balance (stable [SSBT], unstable [USBT] stork balance test; stable [SYBT], unstable [UYBT] Y balance test) was conducted pre-and post-training. An ANCO-VA model was used to test for between-group differences (SPT vs. UPT) at post-test using baseline values as covariates. No significant differences were found for CMJ height (p > 0.05, d = 0.54), SLJ (p > 0.05; d = 0.81), 10-m, 20-m, and 30-m sprint performances (p > 0.05, d = 0.00-0.24), IAT (p > 0.05, d = 0.48), and dynamic balance (SYBT and UYBT, both p > 0.05, d = 0.39, 0.08, respectively). Statistically significant between-group differences were detected for the USBT (p < 0.01, d = 1.86) and the SSBT (p < 0.01, d = 1.75) in favor of UPT. Following 8 weeks of SPT or UPT in prepuberal athletes, similar performance levels were observed in both groups for measures of jumping ability, speed, dynamic balance, and agility. However, if the goal is to additionally enhance static balance, UPT has an advantage over SPT.}, language = {en} } @article{WiesmeierDalinWehrleetal.2017, author = {Wiesmeier, Isabella K. and Dalin, Daniela and Wehrle, Anja and Granacher, Urs and Muehlbauer, Thomas and Dietterle, J{\"o}rg and Weiller, Cornelius and Gollhofer, Albert and Maurer, Christoph}, title = {Balance training enhances vestibular function and reduces overactive proprioceptive feedback in elderly}, series = {Frontiers in aging neuroscience}, volume = {9}, journal = {Frontiers in aging neuroscience}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1663-4365}, doi = {10.3389/fnagi.2017.00273}, pages = {13}, year = {2017}, abstract = {Objectives: Postural control in elderly people is impaired by degradations of sensory, motor, and higher-level adaptive mechanisms. Here, we characterize the effects of a progressive balance training programon these postural control impairments using a brain network model based on system identification techniques. Methods and Material: We analyzed postural control of 35 healthy elderly subjects and compared findings to data from 35 healthy young volunteers. Eighteen elderly subjects performed a 10 week balance training conducted twice per week. Balance training was carried out in static and dynamic movement states, on support surfaces with different elastic compliances, under different visual conditions and motor tasks. Postural control was characterized by spontaneous sway and postural reactions to pseudorandom anterior-posterior tilts of the support surface. Data were interpreted using a parameter identification procedure based on a brain network model. Conclusion: Balance training reduced overactive proprioceptive feedback and restored vestibular orientation in elderly. Based on the assumption of a linear deterioration of postural control across the life span, the training effect can be extrapolated as a juvenescence of 10 years. This study points to a considerable benefit of a continuous balance training in elderly, even without any sensorimotor deficits.}, language = {en} } @misc{BehmYoungWhittenetal.2017, author = {Behm, David George and Young, James D. and Whitten, Joseph H. D. and Reid, Jonathan C. and Quigley, Patrick J. and Low, Jonathan and Li, Yimeng and Lima, Camila D. and Hodgson, Daniel D. and Chaouachi, Anis and Prieske, Olaf and Granacher, Urs}, title = {Effectiveness of Traditional Strength vs. Power Training on Muscle Strength, Power and Speed with Youth: A Systematic Review and Meta-Analysis}, series = {Frontiers in physiology}, volume = {8}, journal = {Frontiers in physiology}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-042X}, doi = {10.3389/fphys.2017.00423}, pages = {37}, year = {2017}, abstract = {Numerous national associations and multiple reviews have documented the safety and efficacy of strength training for children and adolescents. The literature highlights the significant training-induced increases in strength associated with youth strength training. However, the effectiveness of youth strength training programs to improve power measures is not as clear. This discrepancy may be related to training and testing specificity. Most prior youth strength training programs emphasized lower intensity resistance with relatively slow movements. Since power activities typically involve higher intensity, explosive-like contractions with higher angular velocities (e.g., plyometrics), there is a conflict between the training medium and testing measures. This meta-analysis compared strength (e.g., training with resistance or body mass) and power training programs (e.g., plyometric training) on proxies of muscle strength, power, and speed. A systematic literature search using a Boolean Search Strategy was conducted in the electronic databases PubMed, SPORT Discus, Web of Science, and Google Scholar and revealed 652 hits. After perusal of title, abstract, and full text, 107 studies were eligible for inclusion in this systematic review and meta-analysis. The meta-analysis showed small to moderate magnitude changes for training specificity with jump measures. In other words, power training was more effective than strength training for improving youth jump height. For sprint measures, strength training was more effective than power training with youth. Furthermore, strength training exhibited consistently large magnitude changes to lower body strength measures, which contrasted with the generally trivial, small and moderate magnitude training improvements of power training upon lower body strength, sprint and jump measures, respectively. Maturity related inadequacies in eccentric strength and balance might influence the lack of training specificity with the unilateral landings and propulsions associated with sprinting. Based on this meta-analysis, strength training should be incorporated prior to power training in order to establish an adequate foundation of strength for power training activities.}, language = {en} } @article{GschwindBridenbaughReinhardetal.2017, author = {Gschwind, Yves J. and Bridenbaugh, Stephanie A. and Reinhard, Sarah and Granacher, Urs and Monsch, Andreas U. and Kressig, Reto W.}, title = {Ginkgo biloba special extract LI 1370 improves dual-task walking in patients with MCI: a randomised, double-blind, placebo-controlled exploratory study}, series = {Aging clinical and experimental research}, volume = {29}, journal = {Aging clinical and experimental research}, publisher = {Springer}, address = {New York}, issn = {1594-0667}, doi = {10.1007/s40520-016-0699-y}, pages = {609 -- 619}, year = {2017}, abstract = {Background In patients with mild cognitive impairment (MCI), gait instability, particularly in dual-task situations, has been associated with impaired executive function and an increased fall risk. Ginkgo biloba extract (GBE) could be an effective mean to improve gait stability. Aims This study investigated the effect of GBE on spatiotemporal gait parameters of MCI patients while walking under single and dual-task conditions. Methods Fifty patients aged 50-85 years with MCI and associated dual-task-related gait impairment participated in this randomised, double-blind, placebo-controlled, exploratory phase IV drug trial. Intervention group (IG) patients received GBE (Symfona (R) forte 120 mg) twice-daily for 6 months while control group (CG) patients received placebo capsules. A 6-month open-label phase with identical GBE dosage followed. Gait was quantified at months 0, 3, 6 and 12. Results After 6 months, dual-task-related cadence increased in the IG compared to the CG (p = 0.019, d = 0.71). No significant changes, but GBE-associated numerical non-significant trends were found after 6-month treatment for dual-task-related gait velocity and stride time variability. Discussion Findings suggest that 120 mg of GBE twice-daily for at least 6 months may improve dual-task-related gait performance in patients with MCI. Conclusions The observed gait improvements add to the understanding of the self-reported unspecified improvements among MCI patients when treated with standardised GBE.}, language = {en} } @article{NegraChaabeneHammamietal.2016, author = {Negra, Yassine and Chaabene, Helmi and Hammami, Mehrez and Hachana, Younes and Granacher, Urs}, title = {EFFECTS OF HIGH-VELOCITY RESISTANCE TRAINING ON ATHLETIC PERFORMANCE IN PREPUBERAL MALE SOCCER ATHLETES}, series = {Journal of strength and conditioning research : the research journal of the NSCA}, volume = {30}, journal = {Journal of strength and conditioning research : the research journal of the NSCA}, publisher = {Wiley-Blackwell}, address = {Philadelphia}, issn = {1064-8011}, doi = {10.1519/JSC.0000000000001433}, pages = {3290 -- 3297}, year = {2016}, abstract = {The aim of this study was to assess the effectiveness of a 12-week in-season low-to-moderate load high-velocity resistance training (HVRT) in addition to soccer training as compared with soccer training only on proxies of athletic performance in prepubertal soccer players. Twenty-four male soccer players performed 2 different protocols: (a) regular soccer training with 5 sessions per week (n = 11; age = 12.7 +/- 0.3 years) and (b) regular soccer training with 3 sessions per week and HVRT with 2 sessions per week (n = 13; age = 12.8 +/- 0.2 years). The outcome measures included tests for the assessment of muscle strength (e.g., 1 repetition maximum [1RM] half-squat tests), jump ability (e.g., countermovement jump, squat jump [SJ], standing long jump [SLJ], and multiple 5-bound tests [MB5s]), linear speed (e.g., 5-, 10-, 20-, and 30-m sprint tests), and change of direction (e.g., T-test and Illinois change of direction test). Results revealed significant group 3 test interactions for the SJ test (p <= 0.05, d = 0.59) and the SLJ test (p < 0.01, d = 0.83). Post hoc tests illustrated significant pre-post changes in the HVRT group (SJ: Delta 22\%, p < 0.001, d = 1.26; SLJ: Delta 15\%, p < 0.001, d = 1.30) but not in the control group. In addition, tendencies toward significant interaction effects were found for the 1RM half-squat (p = 0.08, d = 0.54) and the 10-m sprint test (p = 0.06, d = 0.57). Significant pre-post changes were found for both parameters in the HVRT group only (1RM: Delta 25\%, p < 0.001, d = 1.23; 10-m sprint: Delta 7\%, p < 0.0001, d = 1.47). In summary, in-season low-to-moderate load HVRT conducted in combination with regular soccer training is a safe and feasible intervention that has positive effects on maximal strength, vertical and horizontal jump and sprint performance as compared with soccer training only.}, language = {en} } @article{GrabowYoungByrneetal.2017, author = {Grabow, Lena and Young, James D. and Byrne, Jeannette M. and Granacher, Urs and Behm, David George}, title = {Unilateral Rolling of the Foot did not Affect Non-Local Range of Motion or Balance}, series = {Journal of sports science \& medicine}, volume = {16}, journal = {Journal of sports science \& medicine}, publisher = {Department of Sports Medicine, Medical Faculty of Uludag University}, address = {Bursa}, issn = {1303-2968}, pages = {209 -- 218}, year = {2017}, abstract = {Non-local or crossover (contralateral and non-stretched muscles) increases in range-of-motion (ROM) and balance have been reported following rolling of quadriceps, hamstrings and plantar flexors. Since there is limited information regarding plantar sole (foot) rolling effects, the objectives of this study were to determine if unilateral foot rolling would affect ipsilateral and contralateral measures of ROM and balance in young healthy adults. A randomized within-subject design was to examine non-local effects of unilateral foot rolling on ipsilateral and contralateral limb ankle dorsiflexion ROM and a modified sit-and-reachtest (SRT). Static balance was also tested during a 30 s single leg stance test. Twelve participants performed three bouts of 60 s unilateral plantar sole rolling using a roller on the dominant foot with 60 s rest intervals between sets. ROM and balance measures were assessed in separate sessions at pre-intervention, immediately and 10 minutes post-intervention. To evaluate repeated measures effects, two SRT pre-tests were implemented. Results demonstrated that the second pre-test SRT was 6.6\% higher than the first pre-test (p = 0.009, d = 1.91). There were no statistically significant effects of foot rolling on any measures immediately or 10 min post-test. To conclude, unilateral foot rolling did not produce statistically significant increases in ipsilateral or contralateral dorsiflexion or SRT ROM nor did it affect postural sway. Our statistically non-significant findings might be attributed to a lower degree of roller-induced afferent stimulation due to the smaller volume of myofascia and muscle compared to prior studies. Furthermore, ROM results from studies utilizing a single pre-test without a sufficient warm-up should be viewed critically.}, language = {en} } @article{JafamezhadgeroShadMajlesietal.2017, author = {Jafamezhadgero, Amir Ali and Shad, Morteza Madadi and Majlesi, Mahdi and Granacher, Urs}, title = {A comparison of running kinetics in children with and without genu varus: A cross sectional study}, series = {PLoS one}, volume = {12}, journal = {PLoS one}, publisher = {PLoS}, address = {San Fransisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0185057}, pages = {15}, year = {2017}, abstract = {Introduction Varus knee alignment has been identified as a risk factor for the progression of medial knee osteoarthritis. However, the underlying mechanisms have not been elucidated yet in children. Thus, the aims of the present study were to examine differences in ground reaction forces, loading rate, impulses, and free moment values during running in children with and without genu varus. Methods Thirty-six boys aged 9-14 volunteered to participate in this study. They were divided in two age-matched groups (genu varus versus healthy controls). Body weight adjusted three dimensional kinetic data (Fx, Fy, Fz) were collected during running at preferred speed using two Kistler force plates for the dominant and non-dominant limb. Results Individuals with knee genu varus produced significantly higher (p = .01; d = 1.09; 95\%) body weight adjusted ground reaction forces in the lateral direction (Fx) of the dominant limb compared to controls. On the non-dominant limb, genu varus patients showed significantly higher body weight adjusted ground reaction forces values in the lateral (p = .01; d = 1.08; 86\%) and medial (p < .001; d = 1.55; 102\%) directions (Fx). Further, genu varus patients demonstrated 55\% and 36\% greater body weight adjusted loading rates in the dominant (p < .001; d = 2.09) and non-dominant (p < .001; d = 1.02) leg, respectively. No significant between-group differences were observed for adjusted free moment values (p>.05). Discussion Higher mediolateral ground reaction forces and vertical loading rate amplitudes in boys with genu varus during running at preferred running speed may accelerate the development of progressive joint degeneration in terms of the age at knee osteoarthritis onset. Therefore, practitioners and therapists are advised to conduct balance and strength training programs to improve lower limb alignment and mediolateral control during dynamic movements.}, language = {en} } @article{LesinskiPrieskeBeurskensetal.2017, author = {Lesinski, Melanie and Prieske, Olaf and Beurskens, Rainer and Behm, David George and Granacher, Urs}, title = {Effects of drop height and surface instability on neuromuscular activation during drop jumps}, series = {Scandinavian journal of medicine \& science in sports}, volume = {27}, journal = {Scandinavian journal of medicine \& science in sports}, publisher = {Wiley}, address = {Hoboken}, issn = {0905-7188}, doi = {10.1111/sms.12732}, pages = {1090 -- 1098}, year = {2017}, abstract = {The purpose of this study was to examine whether drop height-induced changes in leg muscle activity during drop jumps (DJ) are additionally modulated by surface condition. Twenty-four healthy participants (23.7 +/- 1.8years) performed DJs on a force plate on stable, unstable, and highly unstable surfaces using different drop heights (i.e., 20cm, 40cm, 60cm). Electromyographic (EMG) activity of soleus (SOL), gastrocnemius (GM), tibialis anterior (TA) muscles and coactivation of TA/SOL and TA/GM were analyzed for time intervals 100ms prior to ground contact (preactivation) and 30-60ms after ground contact [short latency response (SLR)]. Increasing drop heights resulted in progressively increased SOL and GM activity during preactivation and SLR (P<0.01; 1.01 d 5.34) while TA/SOL coactivation decreased (P<0.05; 0.51 d 3.01). Increasing surface instability produced decreased activities during preactivation (GM) and SLR (GM, SOL) (P<0.05; 1.36 d 4.30). Coactivation increased during SLR (P<0.05; 1.50 d 2.58). A significant drop heightxsurface interaction was observed for SOL during SLR. Lower SOL activity was found on unstable compared to stable surfaces for drop heights 40cm (P<0.05; 1.25 d 2.12). Findings revealed that instability-related changes in activity of selected leg muscles are minimally affected by drop height.}, language = {en} } @article{HammamiGranacherMakhloufetal.2016, author = {Hammami, Raouf and Granacher, Urs and Makhlouf, Issam and Behm, David George and Chaouachi, Anis}, title = {SEQUENCING EFFECTS OF BALANCE AND PLYOMETRIC TRAINING ON PHYSICAL PERFORMANCE IN YOUTH SOCCER ATHLETES}, series = {Journal of strength and conditioning research : the research journal of the NSCA}, volume = {30}, journal = {Journal of strength and conditioning research : the research journal of the NSCA}, publisher = {Elsevier}, address = {Philadelphia}, issn = {1064-8011}, doi = {10.1519/JSC.0000000000001425}, pages = {3278 -- 3289}, year = {2016}, abstract = {Balance training may have a preconditioning effect on subsequent power training with youth. There are no studies examining whether the sequencing of balance and plyometric training has additional training benefits. The objective was to examine the effect of sequencing balance and plyometric training on the performance of 12- to 13-year-old athletes. Twenty-four young elite soccer players trained twice per week for 8 weeks either with an initial 4 weeks of balance training followed by 4 weeks of plyometric training (BPT) or 4 weeks of plyometric training proceeded by 4 weeks of balance training (PBT). Testing was conducted pre- and posttraining and included medicine ball throw; horizontal and vertical jumps; reactive strength; leg stiffness; agility; 10-, 20-, and 30-m sprints; Standing Stork balance test; and Y-Balance test. Results indicated that BPT provided significantly greater improvements with reactive strength index, absolute and relative leg stiffness, triple hop test, and a trend for the Y-Balance test (p = 0.054) compared with PBT. Although all other measures had similar changes for both groups, the average relative improvement for the BPT was 22.4\% (d = 1.5) vs. 15.0\% (d = 1.1) for the PBT. BPT effect sizes were greater with 8 of 13 measures. In conclusion, although either sequence of BPT or PBT improved jumping, hopping, sprint acceleration, and Standing Stork and Y-Balance, BPT initiated greater training improvements in reactive strength index, absolute and relative leg stiffness, triple hop test, and the Y-Balance test. BPT may provide either similar or superior performance enhancements compared with PBT.}, language = {en} } @article{PrieskeMuehlbauerKruegeretal.2015, author = {Prieske, Olaf and M{\"u}hlbauer, Thomas and Kr{\"u}ger, Tom and Kibele, Armin and Behm, David George and Granacher, Urs}, title = {Role of the trunk during drop jumps on stable and unstable surfaces}, series = {European journal of applied physiology}, volume = {115}, journal = {European journal of applied physiology}, number = {1}, publisher = {Springer}, address = {New York}, issn = {1439-6319}, doi = {10.1007/s00421-014-3004-9}, pages = {139 -- 146}, year = {2015}, abstract = {The present study investigated associations between trunk muscle strength, jump performance, and lower limb kinematics during drop jumps on stable and unstable surfaces. Next to this behavioral approach, correlations were also computed on a neuromuscular level between trunk and leg muscle activity during the same test conditions. Twenty-nine healthy and physically active subjects (age 23 +/- A 3 years) were enrolled in this study. Peak isokinetic torque (PIT) of the trunk flexors and extensors was assessed separately on an isokinetic device. In addition, tests included drop jumps (DJ) on a force plate under stable and unstable (i.e., balance pad on top of the force plate) surfaces. Lower limb kinematics as well as electromyographic activity of selected trunk and leg muscles were analyzed. Significant positive but small correlations (0.50 a parts per thousand currency sign r a parts per thousand currency sign 0.66, p < 0.05) were detected between trunk extensor PIT and athletic performance measures (i.e., DJ height, DJ performance index), irrespective of surface condition. Further, significant negative but small correlation coefficients were examined between trunk extensor PIT and knee valgus motion under stable and unstable surface conditions (-0.48 a parts per thousand currency sign r a parts per thousand currency sign -0.45, p < 0.05). In addition, significant positive but small correlations (0.45 a parts per thousand currency sign r a parts per thousand currency sign 0.68, p < 0.05) were found between trunk and leg muscle activity, irrespective of surface condition. Behavioral and neuromuscular data from this study indicate that, irrespective of the surface condition (i.e., jumping on stable or unstable ground), the trunk plays a minor role for leg muscle performance/activity during DJ. This implies only limited effects of trunk muscle strengthening on jump performance in the stretch-shortening cycle.}, language = {en} } @article{MuehlbauerPabstGranacheretal.2017, author = {M{\"u}hlbauer, Thomas and Pabst, Jan and Granacher, Urs and Buesch, Dirk}, title = {Validity of the jump-and-reach test in subelite adolescent handball players}, series = {Journal of strength and conditioning research : the research journal of the NSCA}, volume = {31}, journal = {Journal of strength and conditioning research : the research journal of the NSCA}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia}, issn = {1064-8011}, doi = {10.1519/JSC.0000000000001607}, pages = {1282 -- 1289}, year = {2017}, language = {en} } @misc{LesinskiMuehlbauerGranacher2017, author = {Lesinski, Melanie and M{\"u}hlbauer, Thomas and Granacher, Urs}, title = {Concurrent validity of the Gyko inertial sensor system for the assessment of vertical jump height in female sub-elite youth soccer players}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-400967}, pages = {9}, year = {2017}, abstract = {Background: The aim of the present study was to verify concurrent validity of the Gyko inertial sensor system for the assessment of vertical jump height. - Methods: Nineteen female sub-elite youth soccer players (mean age: 14.7 ± 0.6 years) performed three trials of countermovement (CMJ) and squat jumps (SJ), respectively. Maximal vertical jump height was simultaneously quantified with the Gyko system, a Kistler force-plate (i.e., gold standard), and another criterion device that is frequently used in the field, the Optojump system. - Results: Compared to the force-plate, the Gyko system determined significant systematic bias for mean CMJ (-0.66 cm, p < 0.01, d = 1.41) and mean SJ (-0.91 cm, p < 0.01, d = 1.69) height. Random bias was ± 3.2 cm for CMJ and ± 4.0 cm for SJ height and intraclass correlation coefficients (ICCs) were "excellent" (ICC = 0.87 for CMJ and 0.81 for SJ). Compared to the Optojump device, the Gyko system detected a significant systematic bias for mean CMJ (0.55 cm, p < 0.05, d = 0.94) but not for mean SJ (0.39 cm) height. Random bias was ± 3.3 cm for CMJ and ± 4.2 cm for SJ height and ICC values were "excellent" (ICC = 0.86 for CMJ and 0.82 for SJ). - Conclusion: Consequently, apparatus specific regression equations were provided to estimate true vertical jump height for the Kistler force-plate and the Optojump device from Gyko-derived data. Our findings indicate that the Gyko system cannot be used interchangeably with a Kistler force-plate and the Optojump device in trained individuals. It is suggested that practitioners apply the correction equations to estimate vertical jump height for the force-plate and the Optojump system from Gyko-derived data.}, language = {en} } @article{SaeterbakkenStienAndersenetal.2022, author = {Saeterbakken, Atle H. and Stien, Nicolay and Andersen, Vidar and Scott, Suzanne and Cumming, Kristoffer T. and Behm, David G. and Granacher, Urs and Prieske, Olaf}, title = {The effects of trunk muscle training on physical fitness and sport-specific performance in young and adult athletes}, series = {Sports medicine}, volume = {52}, journal = {Sports medicine}, number = {7}, publisher = {Springer}, address = {Northcote}, issn = {0112-1642}, doi = {10.1007/s40279-021-01637-0}, pages = {1599 -- 1622}, year = {2022}, abstract = {Background The role of trunk muscle training (TMT) for physical fitness (e.g., muscle power) and sport-specific performance measures (e.g., swimming time) in athletic populations has been extensively examined over the last decades. However, a recent systematic review and meta-analysis on the effects of TMT on measures of physical fitness and sport-specific performance in young and adult athletes is lacking. Objective To aggregate the effects of TMT on measures of physical fitness and sport-specific performance in young and adult athletes and identify potential subject-related moderator variables (e.g., age, sex, expertise level) and training-related programming parameters (e.g., frequency, study length, session duration, and number of training sessions) for TMT effects. Data Sources A systematic literature search was conducted with PubMed, Web of Science, and SPORTDiscus, with no date restrictions, up to June 2021. Study Eligibility Criteria Only controlled trials with baseline and follow-up measures were included if they examined the effects of TMT on at least one measure of physical fitness (e.g., maximal muscle strength, change-of-direction speed (CODS)/agility, linear sprint speed) and sport-specific performance (e.g., throwing velocity, swimming time) in young or adult competitive athletes at a regional, national, or international level. The expertise level was classified as either elite (competing at national and/or international level) or regional (i.e., recreational and sub-elite). Study Appraisal and Synthesis Methods The methodological quality of TMT studies was assessed using the Physiotherapy Evidence Database (PEDro) scale. A random-effects model was used to calculate weighted standardized mean differences (SMDs) between intervention and active control groups. Additionally, univariate sub-group analyses were independently computed for subject-related moderator variables and training-related programming parameters. Results Overall, 31 studies with 693 participants aged 11-37 years were eligible for inclusion. The methodological quality of the included studies was 5 on the PEDro scale. In terms of physical fitness, there were significant, small-to-large effects of TMT on maximal muscle strength (SMD = 0.39), local muscular endurance (SMD = 1.29), lower limb muscle power (SMD = 0.30), linear sprint speed (SMD = 0.66), and CODS/agility (SMD = 0.70). Furthermore, a significant and moderate TMT effect was found for sport-specific performance (SMD = 0.64). Univariate sub-group analyses for subject-related moderator variables revealed significant effects of age on CODS/agility (p = 0.04), with significantly large effects for children (SMD = 1.53, p = 0.002). Further, there was a significant effect of number of training sessions on muscle power and linear sprint speed (p <= 0.03), with significant, small-to-large effects of TMT for > 18 sessions compared to <= 18 sessions (0.45 <= SMD <= 0.84, p <= 0.003). Additionally, session duration significantly modulated TMT effects on linear sprint speed, CODS/agility, and sport-specific performance (p <= 0.05). TMT with session durations <= 30 min resulted in significant, large effects on linear sprint speed and CODS/agility (1.66 <= SMD <= 2.42, p <= 0.002), whereas session durations > 30 min resulted in significant, large effects on sport-specific performance (SMD = 1.22, p = 0.008). Conclusions Our findings indicate that TMT is an effective means to improve selected measures of physical fitness and sport-specific performance in young and adult athletes.
Independent sub-group analyses suggest that TMT has the potential to improve CODS/agility, but only in children. Additionally, more (> 18) and/or shorter duration (<= 30 min) TMT sessions appear to be more effective for improving lower limb muscle power, linear sprint speed, and CODS/agility in young or adult competitive athletes.}, language = {en} } @misc{BeurskensMuehlbauerGranacher2015, author = {Beurskens, Rainer and M{\"u}hlbauer, Thomas and Granacher, Urs}, title = {Association of dual-task walking performance and leg muscle quality in healthy children}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-75100}, pages = {7}, year = {2015}, abstract = {Background Previous literature mainly introduced cognitive functions to explain performance decrements in dual-task walking, i.e., changes in dual-task locomotion are attributed to limited cognitive information processing capacities. In this study, we enlarge existing literature and investigate whether leg muscular capacity plays an additional role in children's dual-task walking performance. Methods To this end, we had prepubescent children (mean age: 8.7 ± 0.5 years, age range: 7-9 years) walk in single task (ST) and while concurrently conducting an arithmetic subtraction task (DT). Additionally, leg lean tissue mass was assessed. Results Findings show that both, boys and girls, significantly decrease their gait velocity (f = 0.73), stride length (f = 0.62) and cadence (f = 0.68) and increase the variability thereof (f = 0.20-0.63) during DT compared to ST. Furthermore, stepwise regressions indicate that leg lean tissue mass is closely associated with step time and the variability thereof during DT (R2 = 0.44, p = 0.009). These associations between gait measures and leg lean tissue mass could not be observed for ST (R2 = 0.17, p = 0.19). Conclusion We were able to show a potential link between leg muscular capacities and DT walking performance in children. We interpret these findings as evidence that higher leg muscle mass in children may mitigate the impact of a cognitive interference task on DT walking performance by inducing enhanced gait stability.}, language = {en} } @article{BeurskensMuehlbauerGranacher2015, author = {Beurskens, Rainer and M{\"u}hlbauer, Thomas and Granacher, Urs}, title = {Association of dual-task walking performance and leg muscle quality in healthy children}, series = {BMC pediatrics}, volume = {15}, journal = {BMC pediatrics}, number = {2}, publisher = {BioMed Central}, address = {London}, issn = {1471-2431}, doi = {10.1186/s12887-015-0317-8}, year = {2015}, abstract = {Background Previous literature mainly introduced cognitive functions to explain performance decrements in dual-task walking, i.e., changes in dual-task locomotion are attributed to limited cognitive information processing capacities. In this study, we enlarge existing literature and investigate whether leg muscular capacity plays an additional role in children's dual-task walking performance. Methods To this end, we had prepubescent children (mean age: 8.7 ± 0.5 years, age range: 7-9 years) walk in single task (ST) and while concurrently conducting an arithmetic subtraction task (DT). Additionally, leg lean tissue mass was assessed. Results Findings show that both, boys and girls, significantly decrease their gait velocity (f = 0.73), stride length (f = 0.62) and cadence (f = 0.68) and increase the variability thereof (f = 0.20-0.63) during DT compared to ST. Furthermore, stepwise regressions indicate that leg lean tissue mass is closely associated with step time and the variability thereof during DT (R2 = 0.44, p = 0.009). These associations between gait measures and leg lean tissue mass could not be observed for ST (R2 = 0.17, p = 0.19). Conclusion We were able to show a potential link between leg muscular capacities and DT walking performance in children. We interpret these findings as evidence that higher leg muscle mass in children may mitigate the impact of a cognitive interference task on DT walking performance by inducing enhanced gait stability.}, language = {en} } @article{BehmAlizadehDruryetal.2021, author = {Behm, David G. and Alizadeh, Shahab and Drury, Ben and Granacher, Urs and Moran, Jason}, title = {Non-local acute stretching effects on strength performance in healthy young adults}, series = {European journal of applied physiology}, volume = {121}, journal = {European journal of applied physiology}, number = {6}, publisher = {Springer}, address = {Berlin ; Heidelberg}, issn = {1439-6319}, doi = {10.1007/s00421-021-04657-w}, pages = {1517 -- 1529}, year = {2021}, abstract = {Background Static stretching (SS) can impair performance and increase range of motion of a non-exercised or non-stretched muscle, respectively. An underdeveloped research area is the effect of unilateral stretching on non-local force output. Objective The objective of this review was to describe the effects of unilateral SS on contralateral, non-stretched, muscle force and identify gaps in the literature. Methods A systematic literature search following preferred reporting items for systematic review and meta-analyses Protocols guidelines was performed according to prescribed inclusion and exclusion criteria. Weighted means and ranges highlighted the non-local force output response to unilateral stretching. The physiotherapy evidence database scale was used to assess study risk of bias and methodological quality. Results Unilateral stretching protocols from six studies involved 6.3 +/- 2 repetitions of 36.3 +/- 7.4 s with 19.3 +/- 5.7 s recovery between stretches. The mean stretch-induced force deficits exhibited small magnitude effect sizes for both the stretched (-6.7 +/- 7.1\%, d = -0.35: 0.01 to -1.8) and contralateral, non-stretched, muscles (-4.0 +/- 4.9\%, d = , 0.22: 0.08 to 1.1). Control measures exhibited trivial deficits. Conclusion The limited literature examining non-local effects of prolonged SS revealed that both the stretched and contralateral, non-stretched, limbs of young adults demonstrate small magnitude force deficits. However, the frequency of studies with these effects were similar with three measures demonstrating deficits, and four measures showing trivial changes. These results highlight the possible global (non-local) effects of prolonged SS. Further research should investigate effects of lower intensity stretching, upper versus lower body stretching, different age groups, incorporate full warm-ups, and identify predominant mechanisms among others.}, language = {en} } @misc{SariatiHammamiZouhaletal., author = {Sariati, Dorsaf and Hammami, Raouf and Zouhal, Hassane and Clark, Cain Craig Truman and Nebigh, Ammar and Chtara, Moktar and Chortane, Sabri Gaied and Hackney, Anthony C. and Souissi, Nizar and Granacher, Urs and Ben Ounis, Omar}, title = {Improvement of Physical Performance Following a 6 Week Change-of-Direction Training Program in Elite Youth Soccer Players of Different Maturity Levels}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, publisher = {Universit{\"a}t Potsdam}, address = {Potsdam}, issn = {1866-8364}, doi = {10.25932/publishup-54101}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-541019}, pages = {1 -- 8}, abstract = {Background: Change-of-direction (CoD) is a necessary physical ability of a field sport and may vary in youth players according to their maturation status. Objectives: The aim of this study is: to compare the effectiveness of a 6-week CoD training intervention on dynamic balance (CS-YBT), horizontal jump (5JT), speed (10 and 30-m linear sprint times), CoD with (15 m-CoD + B) and without (15 m-CoD) the ball, in youth male soccer players at different levels of maturity [pre- and post-peak height velocity (PHV)]. Materials and Methods: Thirty elite male youth soccer players aged 10-17 years from the Tunisian first division participated in this study. The players were divided into pre- (G1, n = 15) and post-PHV (G2, n = 15) groups. Both groups completed a similar 6-week training program with two sessions per week of four CoD exercises. All players completed the following tests before and after intervention: CS-YBT; 5 JT; 10, 30, and 15 m-CoD; and 15 m-CoD + B, and data were analyzed using ANCOVA. Results: All 30 players completed the study according to the study design and methodology. Adherence rate was 100\% across all groups, and no training or test-related injuries were reported. Pre-PHV and post-PHV groups showed significant amelioration post-intervention for all dependent variables (after test > before test; p < 0.01, d = 0.09-1.51). ANOVA revealed a significant group × time interaction only for CS-YBT (F = 4.45; p < 0.04; η2 = 0.14), 5JT (F = 6.39; p < 0.02; η2 = 0.18), and 15 m-CoD (F = 7.88; p < 0.01; η2 = 0.22). CS-YBT, 5JT, and 15 m-CoD improved significantly in the post-PHV group (+ 4.56\%, effect size = 1.51; + 4.51\%, effect size = 1.05; and -3.08\%, effect size = 0.51, respectively), more than the pre-PHV group (+ 2.77\%, effect size = 0.85; + 2.91\%, effect size = 0.54; and -1.56\%, effect size = 0.20, respectively). Conclusion: The CoD training program improved balance, horizontal jump, and CoD without the ball in male preadolescent and adolescent soccer players, and this improvement was greater in the post-PHV players. The maturity status of the athletes should be considered when programming CoD training for soccer players.}, language = {en} } @misc{ElAshkerChaabeneNegraetal.2018, author = {El-Ashker, Said and Chaabene, Helmi and Negra, Yassine and Prieske, Olaf and Granacher, Urs}, title = {Cardio-Respiratory endurance responses following a simulated 3 x 3 minutes amateur boxing contest in elite level boxers}, series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {675}, issn = {1866-8364}, doi = {10.25932/publishup-47233}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-472338}, pages = {10}, year = {2018}, abstract = {This study aimed at examining physiological responses (i.e., oxygen uptake [VO2] and heart rate [HR]) to a semi-contact 3 x 3-min format, amateur boxing combat simulation in elite level male boxers. Eleven boxers aged 21.4 +/- 2.1 years (body height 173.4 +/- 3.7, body mass 74.9 +/- 8.6 kg, body fat 12.1 +/- 1.9, training experience 5.7 +/- 1.3 years) volunteered to participate in this study. They performed a maximal graded aerobic test on a motor-driven treadmill to determine maximum oxygen uptake (VO2max), oxygen uptake (VO2AT) and heart rate (HRAT) at the anaerobic threshold, and maximal heart rate (HRmax). Additionally, VO2 and peak HR (HRpeak) were recorded following each boxing round. Results showed no significant differences between VO2max values derived from the treadmill running test and VO2 outcomes of the simulated boxing contest (p > 0.05, d = 0.02 to 0.39). However, HRmax and HRpeak recorded from the treadmill running test and the simulated amateur boxing contest, respectively, displayed significant differences regardless of the boxing round (p < 0.01, d = 1.60 to 3.00). In terms of VO2 outcomes during the simulated contest, no significant between-round differences were observed (p = 0.19, d = 0.17 to 0.73). Irrespective of the boxing round, the recorded VO2 was >90\% of the VO2max. Likewise, HRpeak observed across the three boxing rounds were >= 90\% of the HRmax. In summary, the simulated 3 x 3-min amateur boxing contest is highly demanding from a physiological standpoint. Thus, coaches are advised to systematically monitor internal training load for instance through rating of perceived exertion to optimize training-related adaptations and to prevent boxers from overreaching and/or overtraining.}, language = {en} } @article{GolleMuehlbauerWicketal.2015, author = {Golle, Kathleen and M{\"u}hlbauer, Thomas and Wick, Ditmar and Granacher, Urs}, title = {Physical Fitness Percentiles of German Children Aged 9-12 Years}, series = {PLoS ONE}, volume = {10}, journal = {PLoS ONE}, number = {11}, publisher = {Public Library of Science}, address = {Lawrence, Kan.}, issn = {1932-6203}, doi = {10.1371/journal.pone.0142393}, year = {2015}, abstract = {Background Generating percentile values is helpful for the identification of children with specific fitness characteristics (i.e., low or high fitness level) to set appropriate fitness goals (i.e., fitness/health promotion and/or long-term youth athlete development). Thus, the aim of this longitudinal study was to assess physical fitness development in healthy children aged 9-12 years and to compute sex- and age-specific percentile values. Methods Two-hundred and forty children (88 girls, 152 boys) participated in this study and were tested for their physical fitness. Physical fitness was assessed using the 50-m sprint test (i.e., speed), the 1-kg ball push test, the triple hop test (i.e., upper- and lower- extremity muscular power), the stand-and-reach test (i.e., flexibility), the star run test (i.e., agility), and the 9-min run test (i.e., endurance). Age- and sex-specific percentile values (i.e., P10 to P90) were generated using the Lambda, Mu, and Sigma method. Adjusted (for change in body weight, height, and baseline performance) age- and sex-differences as well as the interactions thereof were expressed by calculating effect sizes (Cohen's d). Results Significant main effects of Age were detected for all physical fitness tests (d = 0.40-1.34), whereas significant main effects of Sex were found for upper-extremity muscular power (d = 0.55), flexibility (d = 0.81), agility (d = 0.44), and endurance (d = 0.32) only. Further, significant Sex by Age interactions were observed for upper-extremity muscular power (d = 0.36), flexibility (d = 0.61), and agility (d = 0.27) in favor of girls. Both, linear and curvilinear shaped curves were found for percentile values across the fitness tests. Accelerated (curvilinear) improvements were observed for upper-extremity muscular power (boys: 10-11 yrs; girls: 9-11 yrs), agility (boys: 9-10 yrs; girls: 9-11 yrs), and endurance (boys: 9-10 yrs; girls: 9-10 yrs). Tabulated percentiles for the 9-min run test indicated that running distances between 1,407-1,507 m, 1,479-1,597 m, 1,423-1,654 m, and 1,433-1,666 m in 9- to 12-year-old boys and 1,262-1,362 m, 1,329-1,434 m, 1,392-1,501 m, and 1,415-1,526 m in 9- to 12-year-old girls correspond to a "medium" fitness level (i.e., P40 to P60) in this population. Conclusions The observed differences in physical fitness development between boys and girls illustrate that age- and sex-specific maturational processes might have an impact on the fitness status of healthy children. Our statistical analyses revealed linear (e.g., lower-extremity muscular power) and curvilinear (e.g., agility) models of fitness improvement with age which is indicative of timed and capacity-specific fitness development pattern during childhood. Lastly, the provided age- and sex-specific percentile values can be used by coaches for talent identification and by teachers for rating/grading of children's motor performance.}, language = {en} } @article{ThielePrieskeChaabeneetal.2020, author = {Thiele, Dirk and Prieske, Olaf and Chaabene, Helmi and Granacher, Urs}, title = {Effects of strength training on physical fitness and sport-specific performance in recreational, sub-elite, and elite rowers}, series = {Journal of sports sciences}, volume = {38}, journal = {Journal of sports sciences}, number = {10}, publisher = {Routledge, Taylor \& Francis Group}, address = {Abingdon}, issn = {0264-0414}, doi = {10.1080/02640414.2020.1745502}, pages = {1186 -- 1195}, year = {2020}, abstract = {The purpose of this systematic review with meta-analysis was to examine the effects of strength training (ST) on selected components of physical fitness (e.g., lower/upper limb maximal strength, muscular endurance, jump performance, cardiorespiratory endurance) and sport-specific performance in rowers. Only studies with an active control group were included if they examined the effects of ST on at least one proxy of physical fitness and/or sport-specific performance in rowers. Weighted and averaged standardized mean differences (SMD) were calculated using random-effects models. Subgroup analyses were computed to identify effects of ST type or expertise level on sport-specific performance. Our analyses revealed significant small effects of ST on lower limb maximal strength (SMD = 0.42, p = 0.05) and on sport-specific performance (SMD = 0.32, p = 0.05). Non-significant effects were found for upper limb maximal strength, upper/lower limb muscular endurance, jump performance, and cardiorespiratory endurance. Subgroup analyses for ST type and expertise level showed non-significant differences between the respective subgroups of rowers (p >= 0.32). Our systematic review with meta-analysis indicated that ST is an effective means for improving lower limb maximal strength and sport-specific performance in rowers. However, ST-induced effects are neither modulated by ST type nor rowers' expertise level.}, language = {en} } @misc{SandauChaabeneGranacher2021, author = {Sandau, Ingo and Chaabene, Helmi and Granacher, Urs}, title = {Concurrent validity of barbell force measured from video-based barbell kinematics during the snatch in male elite weightlifters}, series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {716}, issn = {1866-8364}, doi = {10.25932/publishup-52167}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-521678}, pages = {13}, year = {2021}, abstract = {This study examined the concurrent validity of an inverse dynamic (force computed from barbell acceleration [reference method]) and a work-energy (force computed from work at the barbell [alternative method]) approach to measure the mean vertical barbell force during the snatch using kinematic data from video analysis. For this purpose, the acceleration phase of the snatch was analyzed in thirty male medal winners of the 2018 weightlifting World Championships (age: 25.2±3.1 years; body mass: 88.9±28.6 kg). Vertical barbell kinematics were measured using a custom-made 2D real-time video analysis software. Agreement between the two computational approaches was assessed using Bland-Altman analysis, Deming regression, and Pearson product-moment correlation. Further, principal component analysis in conjunction with multiple linear regression was used to assess whether individual differences related to the two approaches are due to the waveforms of the acceleration time-series data. Results indicated no mean difference (p > 0.05; d = -0.04) and an extremely large correlation (r = 0.99) between the two approaches. Despite the high agreement, the total error of individual differences was 8.2\% (163.0 N). The individual differences can be explained by a multiple linear regression model (R2adj = 0.86) on principal component scores from the principal component analysis of vertical barbell acceleration time-series waveforms. Findings from this study indicate that the individual errors of force measures can be associated with the inverse dynamic approach. This approach uses vertical barbell acceleration data from video analysis that is prone to error. Therefore, it is recommended to use the work-energy approach to compute mean vertical barbell force as this approach did not rely on vertical barbell acceleration.}, language = {en} } @article{FernandezFernandezMoyaRamonSantosRosaetal.2021, author = {Fernandez-Fernandez, Jaime and Moya-Ramon, Manuel and Santos-Rosa, Francisco Javier and Gantois, Petrus and Nakamura, Fabio Yuzo and Sanz-Rivas, David and Granacher, Urs}, title = {Within-session sequence of the tennis serve training in youth elite players}, series = {International journal of environmental research and public health}, volume = {18}, journal = {International journal of environmental research and public health}, number = {1}, publisher = {MDPI}, address = {Basel}, issn = {1660-4601}, doi = {10.3390/ijerph18010244}, pages = {15}, year = {2021}, abstract = {The influence of muscular fatigue on tennis serve performance within regular training sessions is unclear. Therefore, the aim of the present study was to examine the within-session sequence of the tennis serve in youth tennis. Twenty-five young male (14.9 +/- 0.9 years) and female (14.5 +/- 0.9 years) players participated in this within-subject crossover study, and they were randomly but sex-matched assigned to different training sequences (serve exercise before tennis training (BTS) or after tennis training (ATS)). Pre- and post-tests included serve velocity performance and accuracy, shoulder strength, and range-of-motion (ROM) performance (internal/external rotation). Results showed that after one week of serve training conducted following the ATS sequence, significant decreases were found in serve performance (e.g., speed and accuracy), with standardized differences ranging from d = 0.29 to 1.13, as well as the shoulder function (strength [d = 0.20 to 1.0] and ROM [d = 0.17 to 0.31]) in both female and male players, compared to the BTS sequence. Based on the present findings, it appears more effective to implement serve training before the regular tennis training in youth players. If applied after training, excessive levels of fatigue may cause shoulder imbalances that could be related to an increased injury risk.}, language = {en} } @article{ZinkeGebelGranacheretal.2019, author = {Zinke, Fridolin and Gebel, Arnd and Granacher, Urs and Prieske, Olaf}, title = {Acute Effects of Short-Term Local Tendon Vibration on Plantar Flexor Torque, Muscle Contractile Properties, Neuromuscular and Brain Activity in Young Athletes}, series = {Journal of sports science \& medicine}, volume = {18}, journal = {Journal of sports science \& medicine}, number = {2}, publisher = {Department of Sports Medicine, Medical Faculty of Uludag University}, address = {Bursa}, issn = {1303-2968}, pages = {327 -- 336}, year = {2019}, abstract = {The purpose of this study was to examine the acute effects of short-term Achilles tendon vibration on plantar flexor torque, twitch contractile properties as well as muscle and cortical activity in young athletes. Eleven female elite soccer players aged 15.6 +/- 0.5 years participated in this study. Three different conditions were applied in randomized order: Achilles tendon vibration (80 Hz) for 30 and 300 s, and a passive control condition (300 s). Tests at baseline and following conditions included the assessment of peak plantar flexor torque during maximum voluntary contraction, electrically evoked muscle twitches (e.g., potentiated twitch peak torque [PT]), and electromyographic (EMG) activity of the plantar flexors. Additionally, electroencephalographic (EEG) activity of the primary motor and somatosensory cortex were assessed during a submaximal dynamic concentric-eccentric plantar flexion exercise using an elastic rubber band. Large-sized main effects of condition were found for EEG absolute alpha-1 and beta-1 band power (p <= 0.011; 1.5 <= d <= 2.6). Post-hoc tests indicated that alpha-1 power was significantly lower at 30 and 300 s (p = 0.009; d = 0.8) and beta-1 power significantly lower at 300 s (p < 0.001; d = 0.2) compared to control condition. No significant effect of condition was found for peak plantar flexor torque, electrical evoked muscle twitches, and EMG activity. In conclusion, short-term local Achilles tendon vibration induced lower brain activity (i.e., alpha-1 and beta-1 band power) but did not affect lower limb peak torque, twitch contractile properties, and muscle activity. Lower brain activity following short-term local Achilles tendon vibration may indicate improved cortical function during a submaximal dynamic exercise in female young soccer players.}, language = {en} } @misc{ChaabenePrieskeLesinskietal.2019, author = {Chaabene, Helmi and Prieske, Olaf and Lesinski, Melanie and Sandau, Ingo and Granacher, Urs}, title = {Short-term seasonal development of anthropometry, body composition, physical fitness, and sport-specific performance in young olympic weightlifters}, series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {685}, issn = {1866-8364}, doi = {10.25932/publishup-47260}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-472609}, pages = {15}, year = {2019}, abstract = {The aim of this study is to monitor short-term seasonal development of young Olympic weightlifters' anthropometry, body composition, physical fitness, and sport-specific performance. Fifteen male weightlifters aged 13.2 ± 1.3 years participated in this study. Tests for the assessment of anthropometry (e.g., body-height, body-mass), body-composition (e.g., lean-body-mass, relative fat-mass), muscle strength (grip-strength), jump performance (drop-jump (DJ) height, countermovement-jump (CMJ) height, DJ contact time, DJ reactive-strength-index (RSI)), dynamic balance (Y-balance-test), and sport-specific performance (i.e., snatch and clean-and-jerk) were conducted at different time-points (i.e., T1 (baseline), T2 (9 weeks), T3 (20 weeks)). Strength tests (i.e., grip strength, clean-and-jerk and snatch) and training volume were normalized to body mass. Results showed small-to-large increases in body-height, body-mass, lean-body-mass, and lower-limbs lean-mass from T1-to-T2 and T2-to-T3 (∆0.7-6.7\%; 0.1 ≤ d ≤ 1.2). For fat-mass, a significant small-sized decrease was found from T1-to-T2 (∆13.1\%; d = 0.4) and a significant increase from T2-to-T3 (∆9.1\%; d = 0.3). A significant main effect of time was observed for DJ contact time (d = 1.3) with a trend toward a significant decrease from T1-to-T2 (∆-15.3\%; d = 0.66; p = 0.06). For RSI, significant small increases from T1-to-T2 (∆9.9\%, d = 0.5) were noted. Additionally, a significant main effect of time was found for snatch (d = 2.7) and clean-and-jerk (d = 3.1) with significant small-to-moderate increases for both tests from T1-to-T2 and T2-to-T3 (∆4.6-11.3\%, d = 0.33 to 0.64). The other tests did not change significantly over time (0.1 ≤ d ≤ 0.8). Results showed significantly higher training volume for sport-specific training during the second period compared with the first period (d = 2.2). Five months of Olympic weightlifting contributed to significant changes in anthropometry, body-composition, and sport-specific performance. However, hardly any significant gains were observed for measures of physical fitness. Coaches are advised to design training programs that target a variety of fitness components to lay an appropriate foundation for later performance as an elite athlete.}, language = {en} } @misc{JebabliGranacherSelmietal.2020, author = {Jebabli, Nidhal and Granacher, Urs and Selmi, Mohamed Amin and Al-Haddabi, Badriya and Behm, David George and Chaouachi, Anis and Haj Sassi, Radhouane}, title = {Listening to preferred music improved running performance without changing the pacing pattern during a 6 minute run test with young male adults}, series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {696}, issn = {1866-8364}, doi = {10.25932/publishup-47188}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-471884}, pages = {12}, year = {2020}, abstract = {Several studies have investigated the effects of music on both submaximal and maximal exercise performance at a constant work-rate. However, there is a lack of research that has examined the effects of music on the pacing strategy during self-paced exercise. The aim of this study was to examine the effects of preferred music on performance and pacing during a 6 min run test (6-MSPRT) in young male adults. Twenty healthy male participants volunteered for this study. They performed two randomly assigned trials (with or without music) of a 6-MSPRT three days apart. Mean running speed, the adopted pacing strategy, total distance covered (TDC), peak and mean heart rate (HRpeak, HRmean), blood lactate (3 min after the test), and rate of perceived exertion (RPE) were measured. Listening to preferred music during the 6-MSPRT resulted in significant TDC improvement (?10\%; p = 0.016; effect size (ES) = 0.80). A significantly faster mean running speed was observed when listening to music compared with no music. The improvement of TDC in the present study is explained by a significant overall increase in speed (main effect for conditions) during the music trial. Music failed to modify pacing patterns as suggested by the similar reversed "J-shaped" profile during the two conditions. Blood-lactate concentrations were significantly reduced by 9\% (p = 0.006, ES = 1.09) after the 6-MSPRT with music compared to those in the control condition. No statistically significant differences were found between the test conditions for HRpeak, HRmean, and RPE. Therefore, listening to preferred music can have positive effects on exercise performance during the 6-MSPRT, such as greater TDC, faster running speeds, and reduced blood lactate levels but has no effect on the pacing strategy.}, language = {en} }