@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{GranacherGruberFoerdereretal.2010, author = {Granacher, Urs and Gruber, Markus and Foerderer, Dominik and Strass, Dieter and Gollhofer, Albert}, title = {Effects of ankle fatigue on functional reflex activity during gait perturbations in young and elderly men}, issn = {0966-6362}, doi = {10.1016/j.gaitpost.2010.03.016}, year = {2010}, abstract = {There is growing evidence that aging and muscle fatigue result in impaired postural reflexes in humans. Therefore, the objective of this study was to examine the effects of ankle fatigue on functional reflex activity (ERA) during gait perturbations in young and elderly men. Twenty-eight young (27.0 +/- 3.1 years, n = 14) and old (67.2 +/- 3.7 years, n = 14) healthy active men participated in this study. Fatigue of the plantarflexors and dorsiflexors was induced by isokinetic contractions. Pre and post-fatigue, subjects were tested for their ability to compensate for decelerating gait perturbations while walking on a treadmill. Latency, ERA of lower extremity muscles and angular velocity of the ankle joint complex were analysed by means of surface electromyography and goniometry. After the fatigue protocol, no significant main and interaction effects were detected for the parameter latency in m. tibialis anterior (TA). For both groups, a significant pre to post-test decrease in ERA in TA (P<.001) was observed coming along with increases in antagonist coactivity (P=.013) and maximal angular velocity of the ankle joint (p=.007). However, no significant group x test interactions were found for the three parameters. Ankle fatigue has an impact on the ability to compensate for gait perturbations in young and elderly adults. However, no significant differences in all analysed parameters were detected between young and elderly subjects. These results may imply that age-related deteriorations in the postural control system do not specifically affect the ability to compensate for gait perturbations under fatigued condition.}, 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{VoelzkeStutzigThorhaueretal.2012, author = {Voelzke, Mathias and Stutzig, Norman and Thorhauer, Hans-Alexander and Granacher, Urs}, title = {Promoting lower extremity strength in elite volleyball players: Effects of two combined training methods}, series = {JOURNAL OF SCIENCE AND MEDICINE IN SPORT}, volume = {15}, journal = {JOURNAL OF SCIENCE AND MEDICINE IN SPORT}, number = {5}, publisher = {ELSEVIER SCI LTD}, address = {OXFORD}, issn = {1440-2440}, doi = {10.1016/j.jsams.2012.02.004}, pages = {457 -- 462}, year = {2012}, abstract = {Objectives: To compare the impact of short term training with resistance plus plyometric training (RT+P) or electromyostimulation plus plyometric training (EMS+P) on explosive force production in elite volleyball players. Design: Sixteen elite volleyball players of the first German division participated in a training study. Methods: The participants were randomly assigned to either the RT+P training group (n = 8) or the EMS+P training group (n= 8). Both groups participated in a 5-week lower extremity exercise program. Pre and post tests included squat jumps (Si), countermovement jumps (CMJ), and drop jumps (DJ) on a force plate. The three-step reach height (RH) was assessed using a custom-made vertec apparatus. Fifteen m straight and lateral sprint (S15s and S15l) were assessed using photoelectric cells with interims at 5 m and 10 m. Results: RT+P training resulted in significant improvements in Si (+2.3\%) and RH (+0.4\%) performance. The EMS+P training group showed significant increases in performance of CMJ (+3.8\%), DJ (+6.4\%), RH (+1.6\%), S15l (-3.8\%) and after 5 m and 10 m of the S15s (-2.6\%; -0.5\%). The comparison of training-induced changes between the two intervention groups revealed significant differences for the Si (p = 0.023) in favor of RT+P and for the S15s after 5 m (p = 0.006) in favor of EMS+P. Conclusions: The results indicate that RT+P training is effective in promoting jump performances and EMS+P training increases jump, speed and agility performances of elite volleyball players. (c) 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.}, 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{MuehlbauerGranacherJockeletal.2013, author = {M{\"u}hlbauer, Thomas and Granacher, Urs and Jockel, Bj{\"o}rn and Kittel, R{\´e}ne}, title = {Analyse der Muskelaktivit{\"a}t therapeutischer Kletter{\"u}bungen}, series = {Sportverletzung, Sportschaden : Grundlagen, Pr{\"a}vention, Rehabilitation}, volume = {27}, journal = {Sportverletzung, Sportschaden : Grundlagen, Pr{\"a}vention, Rehabilitation}, number = {3}, publisher = {Thieme}, address = {Stuttgart}, issn = {0932-0555}, doi = {10.1055/s-0033-1335595}, pages = {162 -- 168}, year = {2013}, abstract = {Background: Therapeutic climbing exercises are employed for the treatment of shoulder-and knee-joint injuries. However, there is a void in the literature regarding muscle activation levels during the performance of these exercises. Thus, the purpose of this study was to investigate differences in muscle activation during therapeutic climbing exercises depending on the degree of task difficulty. Participants/Material and Methods: A sample of 10 healthy subjects (sex: 4 females, 6 males; age: 27 +/- 3 years; climbing experience: 5 +/- 3 years) performed three shoulder girdle (i.e., wide shoulder pull, narrow shoulder pull, shoulder row) and two leg extensor (i.e., ascending frontal, ascending sidewards) exercises. Electromyographic (EMG) data were recorded on the right side for eleven muscles and then normalised using the maximum voluntary contractions for each muscle. Results: With increasing task difficulty, muscle activity in all but one muscle (i.e., m. trapezius ascendens) increased significantly for the three shoulder girdle exercises. For the two leg extensor exercises, an increase in task difficulty produced a tendency towards yet not significantly higher muscle activity. Conclusion: Shoulder row was the most effective therapeutic climbing exercise in the ability to activate muscles while showing the highest EMG signals. The absence of significant differences in muscle activity between the two leg extensor exercises indicates their equivalent use for muscle activation during therapy.}, language = {de} } @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{GschwindKressigLacroixetal.2013, author = {Gschwind, Yves J. and Kressig, Reto W. and Lacroix, Andre and M{\"u}hlbauer, Thomas and Pfenninger, Barbara and Granacher, Urs}, title = {A best practice fall prevention exercise program to improve balance, strength/power, and psychosocial health in older adults - study protocol for a randomized controlled trial}, series = {BMC geriatrics}, volume = {13}, journal = {BMC geriatrics}, number = {4}, publisher = {BioMed Central}, address = {London}, issn = {1471-2318}, doi = {10.1186/1471-2318-13-105}, pages = {13}, year = {2013}, abstract = {Background: With increasing age neuromuscular deficits (e.g., sarcopenia) may result in impaired physical performance and an increased risk for falls. Prominent intrinsic fall-risk factors are age-related decreases in balance and strength / power performance as well as cognitive decline. Additional studies are needed to develop specifically tailored exercise programs for older adults that can easily be implemented into clinical practice. Thus, the objective of the present trial is to assess the effects of a fall prevention program that was developed by an interdisciplinary expert panel on measures of balance, strength / power, body composition, cognition, psychosocial well-being, and falls self-efficacy in healthy older adults. Additionally, the time-related effects of detraining are tested. Methods/Design: Healthy old people (n = 54) between the age of 65 to 80 years will participate in this trial. The testing protocol comprises tests for the assessment of static / dynamic steady-state balance (i.e., Sharpened Romberg Test, instrumented gait analysis), proactive balance (i.e., Functional Reach Test; Timed Up and Go Test), reactive balance (i.e., perturbation test during bipedal stance; Push and Release Test), strength (i.e., hand grip strength test; Chair Stand Test), and power (i.e., Stair Climb Power Test; countermovement jump). Further, body composition will be analysed using a bioelectrical impedance analysis system. In addition, questionnaires for the assessment of psychosocial (i.e., World Health Organisation Quality of Life Assessment-Bref), cognitive (i.e., Mini Mental State Examination), and fall risk determinants (i.e., Fall Efficacy Scale -International) will be included in the study protocol. Participants will be randomized into two intervention groups or the control / waiting group. After baseline measures, participants in the intervention groups will conduct a 12-week balance and strength / power exercise intervention 3 times per week, with each training session lasting 30 min. (actual training time). One intervention group will complete an extensive supervised training program, while the other intervention group will complete a short version (` 3 times 3') that is home-based and controlled by weekly phone calls. Post-tests will be conducted right after the intervention period. Additionally, detraining effects will be measured 12 weeks after program cessation. The control group / waiting group will not participate in any specific intervention during the experimental period, but will receive the extensive supervised program after the experimental period. Discussion: It is expected that particularly the supervised combination of balance and strength / power training will improve performance in variables of balance, strength / power, body composition, cognitive function, psychosocial well-being, and falls self-efficacy of older adults. In addition, information regarding fall risk assessment, dose-response-relations, detraining effects, and supervision of training will be provided. Further, training-induced health-relevant changes, such as improved performance in activities of daily living, cognitive function, and quality of life, as well as a reduced risk for falls may help to lower costs in the health care system. Finally, practitioners, therapists, and instructors will be provided with a scientifically evaluated feasible, safe, and easy-to-administer exercise program for fall prevention.}, language = {en} } @article{LesinskiMuehlbauerBueschetal.2013, author = {Lesinski, Melanie and M{\"u}hlbauer, Thomas and Buesch, Dirk and Granacher, Urs}, title = {Acute Effects of Postactivation Potentiation on Strength and Speed Performance in Athletes}, series = {Sportverletzung, Sportschaden : Grundlagen, Pr{\"a}vention, Rehabilitation}, volume = {27}, journal = {Sportverletzung, Sportschaden : Grundlagen, Pr{\"a}vention, Rehabilitation}, number = {3}, publisher = {Thieme}, address = {Stuttgart}, issn = {0932-0555}, doi = {10.1055/s-0033-1335414}, pages = {147 -- 155}, year = {2013}, abstract = {Background: The contractile history of a muscle or a muscle group can result in an acute enhancement of subsequent muscle force output. This phenomenon is referred to as postactivation potentiation (PAP) and it was frequently substantiated in original research manuscripts, systematic literature reviews, and meta-analyses. However, there is a lack in the literature regarding precise dose-response relations. This literature review describes the main determinants of PAP effects and additionally presents the state of the art regarding the acute effects of PAP protocols on measures of strength, power, and speed in subelite and elite athletes of different sport disciplines. Furthermore, an attempt is made to demonstrate evidence-based information concerning the design of effective PAP protocols. Methods: Our literature search included the electronic databases Pubmed, SportDiscus, and Google Scholar (1995 - March 2013). In total, 23 studies met the inclusionary criteria for review. Results: Findings from our literature review indicate that various conditioning activities produce acute PAP effects in subelite and particularly elite athletes. More specifically, conditioning activities that are characterised by multiple sets, moderate to high intensities (60 - 84 \% of the one repetition maximum), and rest intervals of 7 - 10 min. following the conditioning activity have the potential to induce short-term improvements in muscle force output and sports performance. Conclusion: It is recommended that subelite and particularly elite athletes from strength, power, and speed disciplines apply specifically tailored conditioning activities during the acute preparation process for competition to induce performance enhancing PAP effects.}, language = {de} } @article{MuehlbauerGollhoferGranacher2013, author = {M{\"u}hlbauer, Thomas and Gollhofer, Albert and Granacher, Urs}, title = {Association of balance, strength, and power measures in young adults}, series = {Journal of strength and conditioning research : the research journal of the NSCA}, volume = {27}, journal = {Journal of strength and conditioning research : the research journal of the NSCA}, number = {3}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia}, issn = {1064-8011}, doi = {10.1097/JSC.0b013e31825c2bab}, pages = {582 -- 589}, year = {2013}, abstract = {Muehlbauer, T, Gollhofer, A, and Granacher, U. Association of balance, strength, and power measures in young adults. J Strength Cond Res 27(3): 582-589, 2013-The purpose of this study was to investigate the relationship between variables of static/dynamic balance, isometric strength, and power. Twenty-seven young healthy adults (mean age: 23 6 4 years) performed measurements of static (unperturbed)/dynamic (perturbed) balance, isometric strength (i.e., maximal isometric torque [MIT]; rate of torque development [RTD] of the plantar flexor), and power (i.e., countermovement jump [CMJ] height and power). No significant associations were found between variables of static and dynamic balance (r = -0.090 to + 0.329, p > 0.05) and between measures of static/dynamic balance and isometric strength (r = +0.041 to +0.387, p > 0.05) and static/dynamic balance and power (r = -0.076 to + 0.218, p > 0.05). Significant positive correlations (r) were detected between variables of power and isometric strength ranging from +0.458 to +0.689 (p, 0.05). Furthermore, simple regression analyses revealed that a 10\% increase in mean CMJ height (4.1 cm) was associated with 22.9 N.m and 128.4 N.m.s(-1) better MIT and RTD, respectively. The nonsignificant correlation between static and dynamic balance measures and between static/dynamic balance, isometric strength, and power variables implies that these capacities may be independent of each other and may have to be tested and trained complementarily.}, 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{GranacherLacroixMuehlbaueretal.2013, author = {Granacher, Urs and Lacroix, Andre and M{\"u}hlbauer, Thomas and R{\"o}ttger, Katrin and Gollhofer, Albert}, title = {Effects of core instability strength training on trunk muscle strength, spinal mobility, dynamic balance and functional mobility in older adults}, series = {Gerontology}, volume = {59}, journal = {Gerontology}, number = {2}, publisher = {Karger}, address = {Basel}, issn = {0304-324X}, doi = {10.1159/000343152}, pages = {105 -- 113}, year = {2013}, abstract = {Background: Age-related postural misalignment, balance deficits and strength/power losses are associated with impaired functional mobility and an increased risk of falling in seniors. Core instability strength training (CIT) involves exercises that are challenging for both trunk muscles and postural control and may thus have the potential to induce benefits in trunk muscle strength, spinal mobility and balance performance. Objective: The objective was to investigate the effects of CIT on measures of trunk muscle strength, spinal mobility, dynamic balance and functional mobility in seniors. Methods: Thirty-two older adults were randomly assigned to an intervention group (INT; n = 16, aged 70.8 +/- 4.1 years) that conducted a 9-week progressive CIT or to a control group (n = 16, aged 70.2 +/- 4.5 years). Maximal isometric strength of the trunk flexors/extensors/lateral flexors (right, left)/rotators (right, left) as well as of spinal mobility in the sagittal and the coronal plane was measured before and after the intervention program. Dynamic balance (i.e. walking 10 m on an optoelectric walkway, the Functional Reach test) and functional mobility (Timed Up and Go test) were additionally tested. Results: Program compliance was excellent with participants of the INT group completing 92\% of the training sessions. Significant group x test interactions were found for the maximal isometric strength of the trunk flexors (34\%, p < 0.001), extensors (21\%, p < 0.001), lateral flexors (right: 48\%, p < 0.001; left: 53\%, p < 0.001) and left rotators (42\%, p < 0.001) in favor of the INT group. Further, training-related improvements were found for spinal mobility in the sagittal (11\%, p < 0.001) and coronal plane (11\%, p = 0.06) directions, for stride velocity (9\%, p < 0.05), the coefficient of variation in stride velocity (31\%, p < 0.05), the Functional Reach test (20\%, p < 0.05) and the Timed Up and Go test (4\%, p < 0.05) in favor of the INT group. Conclusion: CIT proved to be a feasible exercise program for seniors with a high adherence rate. Age-related deficits in measures of trunk muscle strength, spinal mobility, dynamic balance and functional mobility can be mitigated by CIT. This training regimen could be used as an adjunct or even alternative to traditional balance and/or resistance training.}, language = {en} } @article{MuehlbauerBesemerWehrleetal.2013, author = {M{\"u}hlbauer, Thomas and Besemer, Carmen and Wehrle, Anja and Gollhofer, Albert and Granacher, Urs}, title = {Relationship between strength; balance and mobility in children aged 7-10 years}, series = {Gait \& posture}, volume = {37}, journal = {Gait \& posture}, number = {1}, publisher = {Elsevier}, address = {Clare}, issn = {0966-6362}, doi = {10.1016/j.gaitpost.2012.06.022}, pages = {108 -- 112}, year = {2013}, abstract = {The purpose of this study was to investigate the association between variables of lower extremity muscle strength, balance, and mobility assessed under various task conditions. Twenty-one healthy children (mean age: 9 +/- 1 years) were tested for their isometric and dynamic strength as well as for their steady-state, proactive, and reactive balance and mobility. Balance and mobility tests were conducted under single and dual task conditions. Significant positive correlations were detected between measures of isometric and dynamic leg muscle strength. Hardly any significant associations were observed between variables of strength and balance/mobility and between measures of steady-state, proactive, and reactive balance. Additionally, no significant correlations were detected between balance/mobility tests performed under single and dual task conditions. The predominately non-significant correlations between different balance components and mobility imply that balance and mobility performance is task specific. Further, strength and balance/mobility 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{GranacherSchellbachKleinetal.2014, author = {Granacher, Urs and Schellbach, J{\"o}rg and Klein, Katja and Prieske, Olaf and Baeyens, Jean-Pierre and M{\"u}hlbauer, Thomas}, title = {Effects of core strength training using stable versus unstable surfaces on physical fitness in adolescents}, series = {BMC sports science, medicine \& rehabilitation}, volume = {6}, journal = {BMC sports science, medicine \& rehabilitation}, publisher = {BioMed Central}, address = {London}, issn = {2052-1847}, doi = {10.1186/2052-1847-6-40}, pages = {11}, year = {2014}, abstract = {Background It has been demonstrated that core strength training is an effective means to enhance trunk muscle strength (TMS) and proxies of physical fitness in youth. Of note, cross-sectional studies revealed that the inclusion of unstable elements in core strengthening exercises produced increases in trunk muscle activity and thus provide potential extra training stimuli for performance enhancement. Thus, utilizing unstable surfaces during core strength training may even produce larger performance gains. However, the effects of core strength training using unstable surfaces are unresolved in youth. This randomized controlled study specifically investigated the effects of core strength training performed on stable surfaces (CSTS) compared to unstable surfaces (CSTU) on physical fitness in school-aged children. Methods Twenty-seven (14 girls, 13 boys) healthy subjects (mean age: 14 ± 1 years, age range: 13-15 years) were randomly assigned to a CSTS (n = 13) or a CSTU (n = 14) group. Both training programs lasted 6 weeks (2 sessions/week) and included frontal, dorsal, and lateral core exercises. During CSTU, these exercises were conducted on unstable surfaces (e.g., TOGU© DYNAIR CUSSIONS, THERA-BAND© STABILITY TRAINER). Results Significant main effects of Time (pre vs. post) were observed for the TMS tests (8-22\%, f = 0.47-0.76), the jumping sideways test (4-5\%, f = 1.07), and the Y balance test (2-3\%, f = 0.46-0.49). Trends towards significance were found for the standing long jump test (1-3\%, f = 0.39) and the stand-and-reach test (0-2\%, f = 0.39). We could not detect any significant main effects of Group. Significant Time x Group interactions were detected for the stand-and-reach test in favour of the CSTU group (2\%, f = 0.54). Conclusions Core strength training resulted in significant increases in proxies of physical fitness in adolescents. However, CSTU as compared to CSTS had only limited additional effects (i.e., stand-and-reach test). Consequently, if the goal of training is to enhance physical fitness, then CSTU has limited advantages over CSTS.}, language = {en} } @article{GolleGranacherHoffmannetal.2014, author = {Golle, Kathleen and Granacher, Urs and Hoffmann, Martin and Wick, Ditmar and M{\"u}hlbauer, Thomas}, title = {Effect of living area and sports club participation on physical fitness in children: a 4 year longitudinal study}, series = {BMC public health}, volume = {14}, journal = {BMC public health}, publisher = {BioMed Central}, address = {London}, issn = {1471-2458}, doi = {10.1186/1471-2458-14-499}, pages = {8}, year = {2014}, abstract = {Background: Cross-sectional studies detected associations between physical fitness, living area, and sports participation in children. Yet, their scientific value is limited because the identification of cause-and-effect relationships is not possible. In a longitudinal approach, we examined the effects of living area and sports club participation on physical fitness development in primary school children from classes 3 to 6. Methods: One-hundred and seventy-two children (age: 9-12 years; sex: 69 girls, 103 boys) were tested for their physical fitness (i.e., endurance [9-min run], speed [50-m sprint], lower- [triple hop] and upper-extremity muscle strength [1-kg ball push], flexibility [stand-and-reach], and coordination [star coordination run]). Living area (i.e., urban or rural) and sports club participation were assessed using parent questionnaire. Results: Over the 4 year study period, urban compared to rural children showed significantly better performance development for upper- (p = 0.009, ES = 0.16) and lower-extremity strength (p < 0.001, ES = 0.22). Further, significantly better performance development were found for endurance (p = 0.08, ES = 0.19) and lower-extremity strength (p = 0.024, ES = 0.23) for children continuously participating in sports clubs compared to their non-participating peers. Conclusions: Our findings suggest that sport club programs with appealing arrangements appear to represent a good means to promote physical fitness in children living in rural areas.}, language = {en} } @article{PrieskeWickGranacher2014, author = {Prieske, Olaf and Wick, Ditmar and Granacher, Urs}, title = {Intrasession and intersession reliability in maximal and explosive isometric torque production of the elbow flexors}, series = {Journal of strength and conditioning research : the research journal of the NSCA}, volume = {28}, journal = {Journal of strength and conditioning research : the research journal of the NSCA}, number = {6}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia}, issn = {1064-8011}, pages = {1771 -- 1777}, year = {2014}, abstract = {The purpose of this study was to assess intrasession and intersession reliability of maximal and explosive isometric torque production of the elbow flexors and its respective neuromuscular activation pattern. Subjects (13 men, age: 24.8 +/- 3.1 years, height: 1.9 +/- 0.1 m, body mass: 83.7 +/- 12.7 kg; and 6 women, age: 26.5 +/- 1.4 years, height: 1.7 +/- 0.1 m, body mass: 62.7 +/- 7.0 kg) were tested and retested 2-7 days later performing unilateral maximal isometric elbow flexions. Absolute (coefficient of variation[CV], test-retest variability[TRV], Bland-Altman plots with 95\% limits of agreement) and relative reliability statistics (intraclass correlation coefficient) were calculated for various mechanical (i.e., maximal isometric torque, rate of torque development, impulse) and electromyographical measures (i.e., mean average voltage) at different time intervals relative to onset of torque (i. e., 30, 50, 100, 200, 300, 400, 100-200 ms). Intraclass correlation coefficient values were >= 0.61 for all mechanical and electromyographical measures and time intervals indicating good to excellent intrasession and intersession reliability. BlandAltman plots confirmed these findings by showing that only 0-2 (<= 3.3\%) data points were beyond the limits of agreement. Regarding torque and electromyographic measures, CV (11.9-32.3\%) and TRV (18.4-53.8\%) values were high during the early intervals of torque development (<= 100 ms) indicating high variability. During the later intervals (>100 ms), lower CV (i. e., 5.0-29.9\%) and TRV values (i.e., 5.4-34.6\%) were observed indicating lower variability. The present study revealed that neuromuscular performance during explosive torque production of the elbow flexors is reproducible in time intervals >100 ms after onset of isometric actions, whereas during earlier time intervals variability is high.}, language = {en} } @article{MuehlbauerMettlerRothetal.2014, author = {M{\"u}hlbauer, Thomas and Mettler, Claude and Roth, Ralf and Granacher, Urs}, title = {One-leg standing performance and muscle activity: Are there limb differences?}, series = {Journal of applied biomechanics}, volume = {30}, journal = {Journal of applied biomechanics}, number = {3}, publisher = {Human Kinetics Publ.}, address = {Champaign}, issn = {1065-8483}, doi = {10.1123/jab.2013-0230}, pages = {407 -- 414}, year = {2014}, abstract = {The purpose of this study was to compare static balance performance and muscle activity during one-leg standing on the dominant and nondominant leg under various sensory conditions with increased levels of task difficulty. Thirty healthy young adults (age: 23 +/- 2 years) performed one-leg standing tests for 30 s under three sensory conditions (ie, eyes open/firm ground; eyes open/foam ground [elastic pad on top of the balance plate]; eyes closed/firm ground). Center of pressure displacements and activity of four lower leg muscles (ie, m. tibialis anterior [TA], m. soleus [SOL], m. gastrocnemius medialis [GAS], m. peroneus longus [PER]) were analyzed. An increase in sensory task difficulty resulted in deteriorated balance performance (P < .001, effect size [ES] = .57-2.54) and increased muscle activity (P < .001, ES = .50-1.11) for all but two muscles (ie, GAS, PER). However, regardless of the sensory condition, one-leg standing on the dominant as compared with the nondominant limb did not produce statistically significant differences in various balance (P > .05, ES = .06-.22) and electromyographic (P > .05, ES = .03-.13) measures. This indicates that the dominant and the nondominant leg can be used interchangeably during static one-leg balance testing in healthy young adults.}, language = {en} } @article{GranacherMuehlbauerGschwindetal.2014, author = {Granacher, Urs and M{\"u}hlbauer, Thomas and Gschwind, Y. J. and Pfenninger, B. and Kressig, R. W.}, title = {Assessment and training of strength and balance for fall prevention in the elderly. Recommendations of an interdisciplinary expert panel}, series = {Zeitschrift f{\"u}r Gerontologie und Geriatrie}, volume = {47}, journal = {Zeitschrift f{\"u}r Gerontologie und Geriatrie}, number = {6}, publisher = {Springer}, address = {Heidelberg}, issn = {0948-6704}, doi = {10.1007/s00391-013-0509-5}, pages = {513 -- 525}, year = {2014}, abstract = {The proportion of elderly people in societies of western industrialized countries is continuously rising. Biologic aging induces deficits in balance and muscle strength/power in old age, which is responsible for an increased prevalence of falls. Therefore, nationwide and easy-to-administer fall prevention programs have to be developed in order to contribute to the autonomy and quality of life in old age and to help reduce the financial burden on the public health care system due to the treatment of fall-related injuries. This narrative (qualitative) literature review deals with a) the reasons for an increased prevalence of falls in old age, b) important clinical tests for fall-risk assessment, and c) evidence-based intervention/training programs for fall prevention in old age. The findings of this literature review are based on a cost-free practice guide that is available to the public (via the internet) and that was created by an expert panel (i.e., geriatricians, exercise scientists, physiotherapists, geriatric therapists). The present review provides the scientific foundation of the practice guide.}, language = {de} } @article{GranacherLacroixRoettgeretal.2014, author = {Granacher, Urs and Lacroix, Andre and Roettger, Katrin and Gollhofer, Albert and M{\"u}hlbauer, Thomas}, title = {Relationships between trunk muscle strength, spinal mobility, and balance performance in older adults}, series = {Journal of aging and physical activity}, volume = {22}, journal = {Journal of aging and physical activity}, number = {4}, publisher = {Human Kinetics Publ.}, address = {Champaign}, issn = {1063-8652}, doi = {10.1123/JAPA.2013-0108}, pages = {490 -- 498}, year = {2014}, abstract = {This study investigated associations between variables of trunk muscle strength (TMS), spinal mobility, and balance in seniors. Thirty-four seniors (sex: 18 female, 16 male; age: 70 +/- 4 years; activity level: 13 +/- 7 hr/week) were tested for maximal isometric strength (MIS) of the trunk extensors, flexors, lateral flexors, rotators, spinal mobility, and steady-state, reactive, and proactive balance. Significant correlations were detected between all measures of TMS and static steady-state balance (r = .43.57, p < .05). Significant correlations were observed between specific measures of TMS and dynamic steady-state balance (r = .42.55, p < .05). No significant correlations were found between all variables of TMS and reactive/proactive balance and between all variables of spinal mobility and balance. Regression analyses revealed that TMS explains between 1-33\% of total variance of the respective balance parameters. Findings indicate that TMS is related to measures of steady-state balance which may imply that TMS promoting exercises should be integrated in strength training for seniors.}, language = {en} } @article{MeyerErnstSchottetal.2015, author = {Meyer, Ursina and Ernst, Dominique and Schott, Silvia and Riera, Claudia and Hattendorf, Jan and Romkes, Jacqueline and Granacher, Urs and G{\"o}pfert, Beat and Kriemler, Susi}, title = {Validation of two accelerometers to determine mechanical loading of physical activities in children}, series = {Journal of sports sciences}, volume = {33}, journal = {Journal of sports sciences}, number = {16}, publisher = {Routledge, Taylor \& Francis Group}, address = {Abingdon}, issn = {0264-0414}, doi = {10.1080/02640414.2015.1004638}, pages = {1702 -- 1709}, year = {2015}, abstract = {The purpose of this study was to assess the validity of accelerometers using force plates (i.e., ground reaction force (GRF)) during the performance of different tasks of daily physical activity in children. Thirteen children (10.1 (range 5.4-15.7)years, 3 girls) wore two accelerometers (ActiGraph GT3X+ (ACT), GENEA (GEN)) at the hip that provide raw acceleration signals at 100Hz. Participants completed different tasks (walking, jogging, running, landings from boxes of different height, rope skipping, dancing) on a force plate. GRF was collected for one step per trial (10 trials) for ambulatory movements and for all landings (10 trials), rope skips and dance procedures. Accelerometer outputs as peak loading (g) per activity were averaged. ANOVA, correlation analyses and Bland-Altman plots were computed to determine validity of accelerometers using GRF. There was a main effect of task with increasing acceleration values in tasks with increasing locomotion speed and landing height (P<0.001). Data from ACT and GEN correlated with GRF (r=0.90 and 0.89, respectively) and between each other (r=0.98), but both accelerometers consistently overestimated GRF. The new generation of accelerometer models that allow raw signal detection are reasonably accurate to measure impact loading of bone in children, although they systematically overestimate GRF.}, 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: Findings from a Longitudinal Study}, series = {PLoS one}, volume = {10}, journal = {PLoS one}, number = {11}, publisher = {PLoS}, address = {San Fransisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0142393}, pages = {17}, 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., P-10 to P-90) 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., P-40 to P-60) 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{BeurskensGollhoferMuehlbaueretal.2015, author = {Beurskens, Rainer and Gollhofer, Albert and M{\"u}hlbauer, Thomas and Cardinale, Marco and Granacher, Urs}, title = {Effects of Heavy-Resistance Strength and Balance Training on Unilateral and Bilateral Leg Strength Performance in Old Adults}, series = {PLoS one}, volume = {10}, journal = {PLoS one}, number = {2}, publisher = {PLoS}, address = {San Fransisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0118535}, pages = {13}, year = {2015}, abstract = {The term "bilateral deficit" (BLD) has been used to describe a reduction in performance during bilateral contractions when compared to the sum of identical unilateral contractions. In old age, maximal isometric force production (MIF) decreases and BLD increases indicating the need for training interventions to mitigate this impact in seniors. In a cross-sectional approach, we examined age-related differences in MIF and BLD in young (age: 20-30 years) and old adults (age: > 65 years). In addition, a randomized-controlled trial was conducted to investigate training-specific effects of resistance vs. balance training on MIF and BLD of the leg extensors in old adults. Subjects were randomly assigned to resistance training (n = 19), balance training (n = 14), or a control group (n = 20). Bilateral heavy-resistance training for the lower extremities was performed for 13 weeks (3 x /week) at 80\% of the one repetition maximum. Balance training was conducted using predominately unilateral exercises on wobble boards, soft mats, and uneven surfaces for the same duration. Pre-and post-tests included uni-and bilateral measurements of maximal isometric leg extension force. At baseline, young subjects outperformed older adults in uni-and bilateral MIF (all p < .001; d = 2.61-3.37) and in measures of BLD (p < .001; d = 2.04). We also found significant increases in uni-and bilateral MIF after resistance training (all p < .001, d = 1.8-5.7) and balance training (all p < .05, d = 1.3-3.2). In addition, BLD decreased following resistance (p < .001, d = 3.4) and balance training (p < .001, d = 2.6). It can be concluded that both training regimens resulted in increased MIF and decreased BLD of the leg extensors (HRT-group more than BAL-group), almost reaching the levels of young adults.}, language = {en} } @article{HowardGranacherBehm2015, author = {Howard, Joshua and Granacher, Urs and Behm, David George}, title = {Trunk extensor fatigue decreases jump height similarly under stable and unstable conditions with experienced jumpers}, series = {European journal of applied physiology}, volume = {115}, journal = {European journal of applied physiology}, number = {2}, publisher = {Springer}, address = {New York}, issn = {1439-6319}, doi = {10.1007/s00421-014-3011-x}, pages = {285 -- 294}, year = {2015}, abstract = {The purpose of this study was to investigate the effects of back extensor fatigue on performance measures and electromyographic (EMG) activity of leg and trunk muscles during jumping on stable and unstable surfaces. Before and after a modified Biering-Sorensen fatigue protocol for the back extensors, countermovement (CMJ) and lateral jumps (LJ) were performed on a force plate under stable and unstable (balance pad on the force plate) conditions. Performance measures for LJ (contact time) and CMJ height and leg and trunk muscles EMG activity were tested in 14 male experienced jumpers during 2 time intervals for CMJ (braking phase, push-off phase) and 5 intervals for LJ (-30 to 0, 0-30, 30-60, 60-90, and 90-120 ms) in non-fatigued and fatigued conditions. A significant main effect of test (fatigue) (p = 0.007, f = 0.57) was observed for CMJ height. EMG analysis showed a significant fatigue-induced decrease in biceps femoris and gastrocnemius activity with CMJ (p = 0.008, f = 0.58 andp = 0.04, f = 0.422, respectively). LJ contact time was not affected by fatigue or surface interaction. EMG activity was significantly lower in the tibialis anterior with LJ following fatigue (p = 0.05, f = 0.405). A test x surface (p = 0.04, f = 0.438) interaction revealed that the non-fatigued unstable CMJ gastrocnemius EMG activity was lower than the non-fatigued stable condition during the onset-of-force phase. The findings revealed that fatiguing the trunk negatively impacts CMJ height and muscle activity during the performance of CMJs. However, skilled jumpers are not additionally affected by a moderately unstable surface as compared to a stable surface.}, language = {en} } @article{PrieskeMuehlbauerKruegeretal.2015, author = {Prieske, Olaf and M{\"u}hlbauer, Thomas and Kr{\"u}ger, Tom and Kibele, A. and Behm, David George and Granacher, Urs}, title = {Sex-Specific effects of surface instability on drop jump and landing biomechanics}, series = {International journal of sports medicine}, volume = {36}, journal = {International journal of sports medicine}, number = {1}, publisher = {Thieme}, address = {Stuttgart}, issn = {0172-4622}, doi = {10.1055/s-0034-1384549}, pages = {75 -- 81}, year = {2015}, abstract = {This study investigated sex-specific effects of surface instability on kinetics and lower extremity kinematics during drop jumping and landing. Ground reaction forces as well as knee valgus and flexion angles were tested in 14 males (age: 23 +/- 2 years) and 14 females (age: 24 +/- 3 years) when jumping and landing on stable and unstable surfaces. Jump height was found to be significantly lower (9 \%, p < 0.001) when drop jumps were performed on unstable vs. stable surface. Significantly higher peak ground reaction forces were observed when jumping was performed on unstable vs. stable surfaces (5 \%, p = 0.022). Regarding frontal plane kinematics during jumping and landing, knee valgus angles were higher on unstable compared to stable surfaces (1932 \%, p < 0.05). Additionally, at the onset of ground contact during landings, females showed higher knee valgus angles than males (222 \%, p = 0.027). Sagittal plane kinematics indicated significantly smaller knee flexion angles (6-35 \%, p < 0.05) when jumping and landing on unstable vs. stable surfaces. During drop jumps and landings, women showed smaller knee flexion angles at ground contact compared to men (27-33 \%, p < 0.05). These findings imply that knee motion strategies were modified by surface instability and sex during drop jumps and landings.}, 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{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{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{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{BeurskensMuehlbauerGranacheretal.2015, author = {Beurskens, Rainer and M{\"u}hlbauer, Thomas and Granacher, Urs and Gollhofer, Albert and Cardinale, Marco}, title = {Effects of heavy-resistance strength and balance training on unilateral and bilateral leg strength performance in old adults}, series = {PLoS one}, journal = {PLoS one}, publisher = {Public Library of Science}, address = {Lawrence, Kan.}, issn = {1932-6203}, doi = {10.1371/journal.pone.0118535}, pages = {13}, year = {2015}, abstract = {The term "bilateral deficit" (BLD) has been used to describe a reduction in performance during bilateral contractions when compared to the sum of identical unilateral contractions. In old age, maximal isometric force production (MIF) decreases and BLD increases indicating the need for training interventions to mitigate this impact in seniors. In a cross-sectional approach, we examined age-related differences in MIF and BLD in young (age: 20-30 years) and old adults (age: >65 years). In addition, a randomized-controlled trial was conducted to investigate training-specific effects of resistance vs. balance training on MIF and BLD of the leg extensors in old adults. Subjects were randomly assigned to resistance training (n = 19), balance training (n = 14), or a control group (n = 20). Bilateral heavy-resistance training for the lower extremities was performed for 13 weeks (3 × / week) at 80\% of the one repetition maximum. Balance training was conducted using predominately unilateral exercises on wobble boards, soft mats, and uneven surfaces for the same duration. Pre- and post-tests included uni- and bilateral measurements of maximal isometric leg extension force. At baseline, young subjects outperformed older adults in uni- and bilateral MIF (all p < .001; d = 2.61-3.37) and in measures of BLD (p < .001; d = 2.04). We also found significant increases in uni- and bilateral MIF after resistance training (all p < .001, d = 1.8-5.7) and balance training (all p < .05, d = 1.3-3.2). In addition, BLD decreased following resistance (p < .001, d = 3.4) and balance training (p < .001, d = 2.6). It can be concluded that both training regimens resulted in increased MIF and decreased BLD of the leg extensors (HRT-group more than BAL-group), almost reaching the levels of young adults.}, language = {en} } @article{HortobagyiLesinskiGaebleretal.2015, author = {Hortob{\´a}gyi, Tibor and Lesinski, Melanie and G{\"a}bler, Martijn and VanSwearingen, Jessie M. and Malatesta, Davide and Granacher, Urs}, title = {Effects of three types of exercise interventions on healthy old adults' gait speed}, series = {Sports medicine}, volume = {45}, journal = {Sports medicine}, publisher = {Springer}, address = {Berlin}, issn = {1179-2035}, doi = {10.1007/s40279-015-0371-2}, pages = {1627 -- 1643}, year = {2015}, abstract = {Background: Habitual walking speed predicts many clinical conditions later in life, but it declines with age. However, which particular exercise intervention can minimize the age-related gait speed loss is unclear. Purpose: Our objective was to determine the effects of strength, power, coordination, and multimodal exercise training on healthy old adults' habitual and fast gait speed. Methods: We performed a computerized systematic literature search in PubMed and Web of Knowledge from January 1984 up to December 2014. Search terms included 'Resistance training', 'power training', 'coordination training', 'multimodal training', and 'gait speed (outcome term). Inclusion criteria were articles available in full text, publication period over past 30 years, human species, journal articles, clinical trials, randomized controlled trials, English as publication language, and subject age C65 years. The methodological quality of all eligible intervention studies was assessed using the Physiotherapy Evidence Database (PEDro) scale. We computed weighted average standardized mean differences of the intervention-induced adaptations in gait speed using a random-effects model and tested for overall and individual intervention effects relative to no-exercise controls. Results: A total of 42 studies (mean PEDro score of 5.0 +/- 1.2) were included in the analyses (2495 healthy old adults; age 74.2 years [64.4-82.7]; body mass 69.9 +/- 4.9 kg, height 1.64 +/- 0.05 m, body mass index 26.4 +/- 1.9 kg/m(2), and gait speed 1.22 +/- 0.18 m/s). The search identified only one power training study, therefore the subsequent analyses focused only on the effects of resistance, coordination, and multimodal training on gait speed. The three types of intervention improved gait speed in the three experimental groups combined (n = 1297) by 0.10 m/s (+/- 0.12) or 8.4 \% (+/- 9.7), with a large effect size (ES) of 0.84. Resistance (24 studies; n = 613; 0.11 m/s; 9.3 \%; ES: 0.84), coordination (eight studies, n = 198; 0.09 m/s; 7.6 \%; ES: 0.76), and multimodal training (19 studies; n = 486; 0.09 m/s; 8.4 \%, ES: 0.86) increased gait speed statistically and similarly. Conclusions: Commonly used exercise interventions can functionally and clinically increase habitual and fast gait speed and help slow the loss of gait speed or delay its onset.}, language = {en} } @article{BeurskensHaegerKliegletal.2016, author = {Beurskens, Rainer and Haeger, Matthias and Kliegl, Reinhold and Roecker, Kai and Granacher, Urs}, title = {Postural Control in Dual-Task Situations}, series = {PLoS one}, volume = {11}, journal = {PLoS one}, number = {1}, publisher = {PLoS}, address = {Lawrence, Kan.}, issn = {1932-6203}, doi = {10.1371/journal.pone.0147392}, pages = {1 -- 15}, year = {2016}, abstract = {Postural control is important to cope with demands of everyday life. It has been shown that both attentional demand (i.e., cognitive processing) and fatigue affect postural control in young adults. However, their combined effect is still unresolved. Therefore, we investigated the effects of fatigue on single- (ST) and dual-task (DT) postural control. Twenty young subjects (age: 23.7 ± 2.7) performed an all-out incremental treadmill protocol. After each completed stage, one-legged-stance performance on a force platform under ST (i.e., one-legged-stance only) and DT conditions (i.e., one-legged-stance while subtracting serial 3s) was registered. On a second test day, subjects conducted the same balance tasks for the control condition (i.e., non-fatigued). Results showed that heart rate, lactate, and ventilation increased following fatigue (all p < 0.001; d = 4.2-21). Postural sway and sway velocity increased during DT compared to ST (all p < 0.001; d = 1.9-2.0) and fatigued compared to non-fatigued condition (all p < 0.001; d = 3.3-4.2). In addition, postural control deteriorated with each completed stage during the treadmill protocol (all p < 0.01; d = 1.9-3.3). The addition of an attention-demanding interference task did not further impede one-legged-stance performance. Although both additional attentional demand and physical fatigue affected postural control in healthy young adults, there was no evidence for an overadditive effect (i.e., fatigue-related performance decrements in postural control were similar under ST and DT conditions). Thus, attentional resources were sufficient to cope with the DT situations in the fatigue condition of this experiment.}, language = {en} } @article{LacroixKressigMuehlbaueretal.2016, author = {Lacroix, Andre and Kressig, Reto W. and M{\"u}hlbauer, Thomas and Gschwind, Yves J. and Pfenninger, Barbara and Bruegger, Othmar and Granacher, Urs}, title = {Effects of a Supervised versus an Uniupervised Combined Balance and Strength Training Program on Balance and Muscle Power in Healthy Older Adults: A Randomized Controlled Trial}, series = {Gerontology}, volume = {62}, journal = {Gerontology}, publisher = {Karger}, address = {Basel}, issn = {0304-324X}, doi = {10.1159/000442087}, pages = {275 -- 288}, year = {2016}, abstract = {Background: Losses in lower extremity muscle strength/power, muscle mass and deficits in static and particularly dynamic balance due to aging are associated with impaired functional performance and an increased fall risk. It has been shown that the combination of balance and strength training (BST) mitigates these age-related deficits. However, it is unresolved whether supervised versus unsupervised BST is equally effective in improving muscle power and balance in older adults. Objective:This study examined the impact of a 12-week BST program followed by 12 weeks of detraining on measures of balance and muscle power in healthy older adults enrolled in supervised (SUP) or unsupervised (UNSUP) training. Methods: Sixty-six older adults (men: 25, women: 41; age 73 4 years) were randomly assigned to a SUP group (2/week supervised training, 1/week unsupervised training; n = 22), an UNSUP group (3/week unsupervised training; n = 22) or a passive control group (CON; n = 22). Static (i.e., Romberg Test) and dynamic (i.e., 10-meter walk test) steady-state, proactive (i.e., Timed Up and Go Test, Functional Reach Test), and reactive balance (e.g., Push and Release Test), as well as lower extremity muscle power (i.e., Chair Stand Test; Stair Ascent and Descent Test) were tested before and after the active training phase as well as after detraining. Results: Adherence rates to training were 92\% for SUP and 97\% for UNSUP. BST resulted in significant group x time interactions. Post hoc analyses showed, among others, significant training-related improvements for the Romberg Test, stride velocity, Timed Up and Go Test, and Chair Stand Test in favor of the SUP group. Following detraining, significantly enhanced performances (compared to baseline) were still present in 13 variables for the SUP group and in 10 variables for the UNSUP group. Conclusion: Twelve weeks of BST proved to be safe (no training-related injuries) and feasible (high attendance rates of >90\%). Deficits of balance and lower extremity muscle power can be mitigated by BST in healthy older adults. Additionally, supervised as compared to unsupervised BST was more effective. Thus, it is recommended to counteract intrinsic fall risk factors by applying supervised BST programs for older adults. (C) 2015 The Author(s) Published by S. Karger AG, Basel}, language = {en} } @article{BeurskensHaegerKliegletal.2016, author = {Beurskens, Rainer and Haeger, Matthias and Kliegl, Reinhold and Roecker, Kai and Granacher, Urs}, title = {Postural Control in Dual-Task Situations: Does Whole-Body Fatigue Matter?}, series = {PLoS one}, volume = {11}, journal = {PLoS one}, publisher = {PLoS}, address = {San Fransisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0147392}, pages = {1379 -- 1384}, year = {2016}, abstract = {Postural control is important to cope with demands of everyday life. It has been shown that both attentional demand (i.e., cognitive processing) and fatigue affect postural control in young adults. However, their combined effect is still unresolved. Therefore, we investigated the effects of fatigue on single-(ST) and dual-task (DT) postural control. Twenty young subjects (age: 23.7 +/- 2.7) performed an all-out incremental treadmill protocol. After each completed stage, one-legged-stance performance on a force platform under ST (i.e., one-legged-stance only) and DT conditions (i.e., one-legged-stance while subtracting serial 3s) was registered. On a second test day, subjects conducted the same balance tasks for the control condition (i.e., non-fatigued). Results showed that heart rate, lactate, and ventilation increased following fatigue (all p < 0.001; d = 4.2-21). Postural sway and sway velocity increased during DT compared to ST (all p < 0.001; d = 1.9-2.0) and fatigued compared to non-fatigued condition (all p < 0.001; d = 3.3-4.2). In addition, postural control deteriorated with each completed stage during the treadmill protocol (all p < 0.01; d = 1.9-3.3). The addition of an attention-demanding interference task did not further impede one-legged-stance performance. Although both additional attentional demand and physical fatigue affected postural control in healthy young adults, there was no evidence for an overadditive effect (i.e., fatigue-related performance decrements in postural control were similar under ST and DT conditions). Thus, attentional resources were sufficient to cope with the DT situations in the fatigue condition of this experiment.}, language = {en} } @article{PrieskeMuehlbauerBordeetal.2016, author = {Prieske, Olaf and M{\"u}hlbauer, Thomas and Borde, Ron and Gube, M. and Bruhn, S. and Behm, David George and Granacher, Urs}, title = {Neuromuscular and athletic performance following core strength training in elite youth soccer: Role of instability}, series = {Learning and individual differences}, volume = {26}, journal = {Learning and individual differences}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0905-7188}, doi = {10.1111/sms.12403}, pages = {48 -- 56}, year = {2016}, abstract = {Cross-sectional studies revealed that inclusion of unstable elements in core-strengthening exercises produced increases in trunk muscle activity and thus potential extra stimuli to induce more pronounced performance enhancements in youth athletes. Thus, the purpose of the study was to investigate changes in neuromuscular and athletic performance following core strength training performed on unstable (CSTU) compared with stable surfaces (CSTS) in youth soccer players. Thirty-nine male elite soccer players (age: 17 +/- 1 years) were assigned to two groups performing a progressive core strength-training program for 9 weeks (2-3 times/week) in addition to regular in-season soccer training. CSTS group conducted core exercises on stable (i.e., floor, bench) and CSTU group on unstable (e.g., Thera-Band (R) Stability Trainer, Togu (c) Swiss ball) surfaces. Measurements included tests for assessing trunk muscle strength/activation, countermovement jump height, sprint time, agility time, and kicking performance. Statistical analysis revealed significant main effects of test (pre vs post) for trunk extensor strength (5\%, P<0.05, d=0.86), 10-20-m sprint time (3\%, P<0.05, d=2.56), and kicking performance (1\%, P<0.01, d=1.28). No significant Groupxtest interactions were observed for any variable. In conclusion, trunk muscle strength, sprint, and kicking performance improved following CSTU and CSTS when conducted in combination with regular soccer training.}, language = {en} } @article{WallentaGranacherLesinskietal.2016, author = {Wallenta, Christopher and Granacher, Urs and Lesinski, Melanie and Schuenemann, C. and M{\"u}hlbauer, Thomas}, title = {Effects of Complex Versus Block Strength Training on the Athletic Performance of Elite Youth Soccer Players}, series = {Sportverletzung, Sportschaden : Grundlagen, Pr{\~A}\ivention, Rehabilitation}, volume = {30}, journal = {Sportverletzung, Sportschaden : Grundlagen, Pr{\~A}\ivention, Rehabilitation}, publisher = {Thieme}, address = {Stuttgart}, issn = {0932-0555}, doi = {10.1055/s-0041-106949}, pages = {31 -- 37}, year = {2016}, abstract = {Hintergrund: Kraft und Schnelligkeit stellen bedeutsame leistungsdeterminierende Faktoren im Fußball dar. Durch Komplextraining (Kombination aus Kraft- und plyometrischen {\"U}bungen in einer Trainingseinheit) lassen sich Kraft- und Schnelligkeitswerte von Athleten steigern. Unklar ist jedoch, ob ein Komplextraining (KT) gegen{\"u}ber einem herk{\"o}mmlichen blockweisen Krafttraining (BT) zu gr{\"o}ßeren sportmotorischen Leistungssteigerungen f{\"u}hrt. Das Ziel der Studie war es, die Effekte von KT versus BT auf Variablen der Kraft, Schnelligkeit und Gewandtheit von Nachwuchsleistungsfußballern zu untersuchen. Methode: Zus{\"a}tzlich zum regul{\"a}ren Fußballtraining (ca. 6 × pro Woche, je 60 - 90 min.) f{\"u}hrten 18 m{\"a}nnliche Nachwuchsleistungsfußballer {\"u}ber sechs Wochen (2 × pro Woche, je 30 min.) entweder ein progressives KT (n = 10, Alter: 18,5 ± 2,2 Jahre) oder BT (n = 8, Alter: 18,1 ± 1,6 Jahre) durch. Vor und nach dem Training wurden Tests zur Erfassung der Kraft (Einer-Wiederholungs-Maximum [EWM] Kniebeuge), der Sprungkraft (Hockstrecksprung [HSS]), der Schnelligkeit (30-m-Sprint) und der Gewandtheit (T-Test) durchgef{\"u}hrt. Es wurden parameterfreie Verfahren zur Bestimmung von Unterschieden innerhalb (Wilcoxon-Test) und zwischen (Mann-Whitney-U-Test) den beiden Gruppen gerechnet. Ergebnisse: Sowohl KT als auch BT sind sichere (keine trainings- aber sechs spielbedingte Verletzungen) und geeignete (Trainingsteilnahme in KT und BT: \&\#8805; 80 \%) Trainingsmaßnahmen in Erg{\"a}nzung zum regul{\"a}ren Fußballtraining. Die statistische Analyse ergab signifikante Verbesserungen vom Pr{\"a}- zum Posttest f{\"u}r die KT-Gruppe im EWM (p = 0,043) und im HSS (p = 0,046) sowie f{\"u}r die BT-Gruppe in der Sprintzeit {\"u}ber 5 m (p = 0,039) und 10 m (p = 0,026). Zudem zeigten sich f{\"u}r beide Gruppen signifikante Verbesserungen im T-Test (KT: p = 0,046; BT: p = 0,027). Der Gruppenvergleich (KT vs. BT) {\"u}ber die Zeit (Post- minus Pr{\"a}test) offenbarte keine bedeutsamen Unterschiede. Schlussfolgerung: Sowohl sechsw{\"o}chiges KT als auch BT f{\"u}hrten zu signifikanten Verbesserungen sportmotorischer Leistungen bei Nachwuchsleistungsfußballern. Allerdings konnten keine zus{\"a}tzlich leistungssteigernden Effekte von KT im Vergleich zu BT ermittelt werden. In zuk{\"u}nftigen Studien sollte gepr{\"u}ft werden, ob die beobachteten testspezifischen Ver{\"a}nderungen, d. h. Verbesserung der Kraft/Sprungkraft in der KT-Gruppe und Verbesserung der Schnelligkeit in der BT-Gruppe der gew{\"a}hlten {\"U}bungsanordnung geschuldet sind oder einen generellen Effekt darstellen. Background: Muscle strength and speed are important determinants of soccer performance. It has previously been shown that complex training (CT, combination of strength and plyometric exercises within a single training session) is effective to enhance strength and speed performance in athletes. However, it is unresolved whether CT is more effective than conventional strength training that is delivered in one single block (BT) to increase proxies of athletic performance. Thus, the aim of the present study was to investigate the effects of CT versus BT on measures of muscle strength/power, speed, and agility in elite youth soccer players. Methods: Eighteen male elite youth soccer players conducted six weeks (2 sessions/week, 30 min, each) of progressive CT (n = 10, age: 18,5 +/- 2.2 years) or BT (n=8, age: 18.1 +/- 1.6 years) in addition to their regular soccer training (approx. 6 sessions/week, 60-90 min, each). Before and after training, tests were conducted for the assessment of strength (one -repetition maximum [1RM] squat), power (countermovement jump [CMJ]), speed (30-m linear sprint), and agility (T test). Non-parametric analyses were used to calculate differences within (Wilcoxon test) and between (Mann-Whitney-U test) groups. Results: Both CT and BT proved to be safe (i.e. no training-related, but six match -related injuries reported) and feasible (i.e. attendance rate of 80\% in both groups) training regimens when implemented in addition to regular soccer training. The statistical analysis revealed significant improvements from pre-training to post-training tests for the CT group in 1 RM squat (p =0.043) and CMJ height (p =0,046). For the BT -group, significantly enhanced sprint times were observed over 5 m (p = 0.039) and 10 m (p = 0.026), Furthermore, both groups significantly improved their t test time (CT: p =0.046; BT: p =0.027). However, group comparisons (CT vs. BT) over time (post-training minus pre-training test) did not show any significant differences. Conclusion: Six weeks of CT and BT resulted in significant improvements in proxies of athletic performance. Yet CT did not produce any additional effects compared to BT. Future research is needed to examine whether the observed test-specific changes, i.e. improvements in strength/power for the CT-group and improvements in speed for the BT-group, are due to the applied configuration of strength, plyometric, and sprint exercises or if they rather indicate a general training response.}, language = {de} } @article{BeurskensSteinbergAntoniewiczetal.2016, author = {Beurskens, Rainer and Steinberg, Fabian and Antoniewicz, Franziska and Wolff, Wanja and Granacher, Urs}, title = {Neural Correlates of Dual-Task Walking: Effects of Cognitive versus Motor Interference in Young Adults}, series = {Neural plasticity}, journal = {Neural plasticity}, publisher = {Hindawi}, address = {London}, issn = {2090-5904}, doi = {10.1155/2016/8032180}, pages = {9}, year = {2016}, abstract = {Walking while concurrently performing cognitive and/or motor interference tasks is the norm rather than the exception during everyday life and there is evidence from behavioral studies that it negatively affects human locomotion. However, there is hardly any information available regarding the underlying neural correlates of single-and dual-task walking. We had 12 young adults (23.8 +/- 2.8 years) walk while concurrently performing a cognitive interference (CI) or a motor interference (MI) task. Simultaneously, neural activation in frontal, central, and parietal brain areas was registered using a mobile EEG system. Results showed that the MI task but not the CI task affected walking performance in terms of significantly decreased gait velocity and stride length and significantly increased stride time and tempo-spatial variability. Average activity in alpha and beta frequencies was significantly modulated during both CI and MI walking conditions in frontal and central brain regions, indicating an increased cognitive load during dual-task walking. Our results suggest that impaired motor performance during dual-task walking is mirrored in neural activation patterns of the brain. This finding is in line with established cognitive theories arguing that dual-task situations overstrain cognitive capabilities resulting in motor performance decrements.}, language = {en} } @article{BeijersbergenHortobagyiBeurskensetal.2016, author = {Beijersbergen, Chantal M. I. and Hortobagyi, Tibor and Beurskens, Rainer and Lenzen-Grossimlinghaus, Romana and Gabler, Martijn and Granacher, Urs}, title = {Effects of Power Training on Mobility and Gait Biomechanics in Old Adults with Moderate Mobility Disability: Protocol and Design of the Potsdam Gait Study (POGS)}, series = {Gerontology}, volume = {62}, journal = {Gerontology}, publisher = {Karger}, address = {Basel}, issn = {0304-324X}, doi = {10.1159/000444752}, pages = {597 -- 603}, year = {2016}, abstract = {Background: Walking speed decreases in old age. Even though old adults regularly participate in exercise interventions, we do not know how the intervention-induced changes in physical abilities produce faster walking. The Potsdam Gait Study (POGS) will examine the effects of 10 weeks of power training and detraining on leg muscle power and, for the first time, on complete gait biomechanics, including joint kinematics, kinetics, and muscle activation in old adults with moderate mobility disability. Methods/Design: POGS is a randomized controlled trial with two arms, each crossed over, without blinding. Arm 1 starts with a 10-week control period to assess the reliability of the tests and is then crossed over to complete 25-30 training sessions over 10 weeks. Arm 2 completes 25-30 exercise sessions over 10 weeks, followed by a 10-week follow-up (detraining) period. The exercise program is designed to improve lower extremity muscle power. Main outcome measures are: muscle power, gait speed, and gait biomechanics measured at baseline and after 10 weeks of training and 10 weeks of detraining. Discussion: It is expected that power training will increase leg muscle power measured by the weight lifted and by dynamometry, and these increased abilities become expressed in joint powers measured during gait. Such favorably modified powers will underlie the increase in step length, leading ultimately to a faster walking speed. POGS will increase our basic understanding of the biomechanical mechanisms of how power training improves gait speed in old adults with moderate levels of mobility disabilities. (C) 2016 S. Karger AG, Basel}, 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{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{LesinskiPrieskeDempsetal.2016, author = {Lesinski, Melanie and Prieske, Olaf and Demps, Marie and Granacher, Urs}, title = {Effects of fatigue and surface instability on neuromuscular performance during jumping}, series = {Der Schmerz : Organ der Deutschen Gesellschaft zum Studium des Schmerzes, der {\~A}-sterreichischen Schmerzgesellschaft und der Deutschen Interdisziplin{\~A}\iren Vereinigung f{\~A}¼r Schmerztherapie}, volume = {26}, journal = {Der Schmerz : Organ der Deutschen Gesellschaft zum Studium des Schmerzes, der {\~A}-sterreichischen Schmerzgesellschaft und der Deutschen Interdisziplin{\~A}\iren Vereinigung f{\~A}¼r Schmerztherapie}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0905-7188}, doi = {10.1111/sms.12548}, pages = {1140 -- 1150}, year = {2016}, abstract = {It has previously been shown that fatigue and unstable surfaces affect jump performance. However, the combination thereof is unresolved. Thus, the purpose of this study was to examine the effects of fatigue and surface instability on jump performance and leg muscle activity. Twenty elite volleyball players (18 +/- 2 years) performed repetitive vertical double-leg box jumps until failure. Before and after a fatigue protocol, jump performance (i.e., jump height) and electromyographic activity of selected lower limb muscles were recorded during drop jumps (DJs) and countermovement jumps (CMJs) on a force plate on stable and unstable surfaces (i.e., balance pad on top of force plate). Jump performance (3-7\%; P < 0.05; 1.14 <= d <= 2.82), and muscle activity (2-27\%; P < 0.05; 0.59 <= d <= 3.13) were lower following fatigue during DJs and CMJs, and on unstable compared with stable surfaces during DJs only (jump performance: 8\%; P < 0.01; d = 1.90; muscle activity: 9-25\%; P < 0.05; 1.08 <= d <= 2.54). No statistically significant interactions of fatigue by surface condition were observed. Our findings revealed that fatigue impairs neuromuscular performance during DJs and CMJs in elite volleyball players, whereas surface instability affects neuromuscular DJ performance only. Absent fatigue x surface interactions indicate that fatigue-induced changes in jump performance are similar on stable and unstable surfaces in jump-trained athletes.}, language = {en} } @article{BeurskensSteinbergAntoniewiczetal.2016, author = {Beurskens, Rainer and Steinberg, Fabian and Antoniewicz, Franziska and Wolff, Wanja and Granacher, Urs}, title = {Neural Correlates of Dual-Task Walking}, series = {Neural plasticity}, volume = {2016}, journal = {Neural plasticity}, publisher = {Hindawi}, address = {New York}, doi = {10.1155/2016/8032180}, pages = {1 -- 9}, year = {2016}, abstract = {Walking while concurrently performing cognitive and/or motor interference tasks is the norm rather than the exception during everyday life and there is evidence from behavioral studies that it negatively affects human locomotion. However, there is hardly any information available regarding the underlying neural correlates of single- and dual-task walking. We had 12 young adults (23.8 ± 2.8 years) walk while concurrently performing a cognitive interference (CI) or a motor interference (MI) task. Simultaneously, neural activation in frontal, central, and parietal brain areas was registered using a mobile EEG system. Results showed that the MI task but not the CI task affected walking performance in terms of significantly decreased gait velocity and stride length and significantly increased stride time and tempo-spatial variability. Average activity in alpha and beta frequencies was significantly modulated during both CI and MI walking conditions in frontal and central brain regions, indicating an increased cognitive load during dual-task walking. Our results suggest that impaired motor performance during dual-task walking is mirrored in neural activation patterns of the brain. This finding is in line with established cognitive theories arguing that dual-task situations overstrain cognitive capabilities resulting in motor performance decrements.}, language = {en} } @article{BeurskensMuehlbauerGrabowetal.2016, author = {Beurskens, Rainer and M{\"u}hlbauer, Thomas and Grabow, Lena and Kliegl, Reinhold and Granacher, Urs}, title = {Effects of Backpack Carriage on Dual-Task Performance in Children During Standing and Walking}, series = {Journal of motor behavior}, volume = {48}, journal = {Journal of motor behavior}, publisher = {Wiley-VCH}, address = {Abingdon}, issn = {0022-2895}, doi = {10.1080/00222895.2016.1152137}, pages = {500 -- 508}, year = {2016}, language = {en} } @article{HammamiChaouachiMakhloufetal.2016, author = {Hammami, Raouf and Chaouachi, Anis and Makhlouf, Issam and Granacher, Urs and Behm, David George}, title = {Associations Between Balance and Muscle Strength, Power Performance in Male Youth Athletes of Different Maturity Status}, series = {Pediatric exercise science}, volume = {28}, journal = {Pediatric exercise science}, publisher = {Human Kinetics Publ.}, address = {Champaign}, issn = {0899-8493}, doi = {10.1123/pes.2015-0231}, pages = {521 -- 534}, year = {2016}, abstract = {Balance, strength and power relationships may contain important information at various maturational stages to determine training priorities. Purpose: The objective was to examine maturity-specific relationships of static/dynamic balance with strength and power measures in young male athletes. Method: Soccer players (N = 130) aged 10-16 were assessed with the Stork and Y balance (YBT) tests. Strength/power measures included back extensor muscle strength, standing long jump (SLJ), countermovement jump (CMJ), and 3-hop jump tests. Associations between balance with strength/power variables were calculated according to peak-height-velocity (PHV). Results: There were significant medium-large sized correlations between all balance measures with back extensor strength (r =.486.791) and large associations with power (r =.511.827). These correlation coefficients were significantly different between pre-PHV and circa PHV as well as pre-PHV and post-PHV with larger associations in the more mature groups. Irrespective of maturity-status, SLJ was the best strength/ power predictor with the highest proportion of variance (12-47\%) for balance (i.e., Stork eyes opened) and the YBT was the best balance predictor with the highest proportion of variance (43-78\%) for all strength/ power variables. Conclusion: The associations between balance and muscle strength/power measures in youth athletes that increase with maturity may imply transfer effects from balance to strength/power training and vice versa in youth athletes.}, language = {en} } @article{KuemmelBergmannPrieskeetal.2016, author = {Kuemmel, Jakob and Bergmann, Julian and Prieske, Olaf and Kramer, Andreas and Granacher, Urs and Gruber, Markus}, title = {Effects of conditioning hops on drop jump and sprint performance: a randomized crossover pilot study in elite athletes}, series = {BMC sports science, medicine \& rehabilitation}, volume = {8}, journal = {BMC sports science, medicine \& rehabilitation}, publisher = {BioMed Central}, address = {London}, issn = {2052-1847}, doi = {10.1186/s13102-016-0027-z}, pages = {8}, year = {2016}, abstract = {Background: It has previously been shown that conditioning activities consisting of repetitive hops have the potential to induce better drop jump (DJ) performance in recreationally active individuals. In the present pilot study, we investigated whether repetitive conditioning hops can also increase reactive jump and sprint performance in sprint-trained elite athletes competing at an international level. Methods: Jump and sprint performances of 5 athletes were randomly assessed under 2 conditions. The control condition (CON) comprised 8 DJs and 4 trials of 30-m sprints. The intervention condition (HOP) consisted of 10 maximal repetitive two-legged hops that were conducted 10 s prior to each single DJ and sprint trial. DJ performance was analyzed using a one-dimensional ground reaction force plate. Step length (SL), contact time (CT), and sprint time (ST) during the 30-m sprints were recorded using an opto-electronic measurement system. Results: Following the conditioning activity, DJ height and external DJ peak power were both significantly increased by 11 \% compared to the control condition. All other variables did not show any significant differences between HOP and CON. Conclusions: In the present pilot study, we were able to demonstrate large improvements in DJ performance even in sprint-trained elite athletes following a conditioning activity consisting of maximal two-legged repetitive hops. This strengthens the hypothesis that plyometric conditioning exercises can induce performance enhancements in elite athletes that are even greater than those observed in recreationally active athletes.. In addition, it appears that the transfer of these effects to other stretch-shortening cycle activities is limited, as we did not observe any changes in sprint performance following the plyometric conditioning activity.}, language = {en} } @article{MuehlbauerGranacherBordeetal.2017, author = {Muehlbauer, Thomas and Granacher, Urs and Borde, Ron and Hortobagyi, Tibor}, title = {Non-Discriminant Relationships between Leg Muscle Strength, Mass and Gait Performance in Healthy Young and Old Adults}, series = {Gerontology}, volume = {64}, journal = {Gerontology}, number = {1}, publisher = {Karger}, address = {Basel}, issn = {0304-324X}, doi = {10.1159/000480150}, pages = {11 -- 18}, year = {2017}, abstract = {Background: Gait speed declines with increasing age, but it is unclear if gait speed preferentially correlates with leg muscle strength or mass. Objective: We determined the relationship between gait speed and (1) leg muscle strength measured at 3 lower extremity joints and (2) leg lean tissue mass (LTM) in healthy young (age: 25 years, n = 20) and old (age: 70 years, n = 20) adults. Methods: Subjects were tested for maximal isokinetic hip, knee, and ankle extension torque, leg LTM by bioimpedance, and gait performance (i.e., gait speed, stride length) at preferred and maximal gait speeds. Results: We found no evidence for a preferential relationship between gait performance and leg muscle strength compared with gait performance and leg LTM in healthy young and old adults. In old adults, hip extensor strength only predicted habitual gait speed (R-2 = 0.29, p = 0.015), whereas ankle plantarflexion strength only predicted maximal gait speed and stride length (both R-2 = 0.40, p = 0.003). Conclusions: Gait speed did not preferentially correlate with leg muscle strength or leg LTM, favoring neither outcome for predicting mobility. Thus, we recommend that both leg muscle strength and leg LTM should be tested and trained complementarily. Further, hip and ankle extension torque predicted gait performance, and thus we recommend to test and train healthy old adults by functional integrated multiarticular rather than monoarticular lower extremity strength exercises.}, language = {en} } @article{NegraChaabeneSammoudetal.2017, author = {Negra, Yassine and Chaabene, Helmi and Sammoud, Senda and Bouguezzi, Raja and Mkaouer, Bessem and Hachana, Younes and Granacher, Urs}, title = {EFFECTS OF PLYOMETRIC TRAINING ON COMPONENTS OF PHYSICAL FITNESS IN PREPUBERAL MALE SOCCER ATHLETES: THE ROLE OF SURFACE INSTABILITY}, 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}, pages = {3295 -- 3304}, year = {2017}, abstract = {Previous studies contrasted the effects of plyometric training (PT) conducted on stable vs. unstable surfaces on components of physical fitness in child and adolescent soccer players. Depending on the training modality (stable vs. unstable), specific performance improvements were found for jump (stable PT) and balance performances (unstable PT). In an attempt to combine the effects of both training modalities, this study examined the effects of PT on stable surfaces compared with combined PT on stable and unstable surfaces on components of physical fitness in prepuberal male soccer athletes. Thirty-three boys were randomly assigned to either a PT on stable surfaces (PTS; n = 17; age = 12.1 +/- 0.5 years; height = 151.6 +/- 5.7 cm; body mass = 39.2 +/- 6.5 kg; and maturity offset = 22.3 +/- 0.5 years) or a combined PT on stable and unstable surfaces (PTC; n = 16; age = 12.2 +/- 0.6 years; height = 154.6 +/- 8.1 cm; body mass = 38.7 +/- 5.0 kg; and maturity offset = 22.2 +/- 0.6 years). Both intervention groups conducted 4 soccer-specific training sessions per week combined with either 2 PTS or PTC sessions. Before and after 8 weeks of training, proxies of muscle power (e.g., countermovement jump [CMJ], standing long jump [SLJ]), muscle strength (e.g., reactive strength index [RSI]), speed (e.g., 20-m sprint test), agility (e.g., modified Illinois change of direction test [MICODT]), static balance (e.g., stable stork bal-ance test [SSBT]), and dynamic balance (unstable stork balance test [USBT]) were tested. An analysis of covariance model was used to test between-group differences (PTS vs. PTC) at posttest using baseline outcomes as covariates. No significant between-group differences at posttest were observed for CMJ (p > 0.05, d = 0.41), SLJ (p > 0.05, d = 0.36), RSI (p > 0.05, d = 0.57), 20-m sprint test (p > 0.05, d = 0.06), MICODT (p > 0.05, d = 0.23), and SSBT (p > 0.05, d = 0.20). However, statistically significant between-group differences at posttest were noted for the USBT (p < 0.01, d = 1.49) in favor of the PTC group. For most physical fitness tests (except RSI), significant pre-to-post improvements were observed for both groups (p < 0.01, d = 0.55-3.96). Eight weeks of PTS or PTC resulted in similar performance improvements in components of physical fitness except for dynamic balance. From a performance-enhancing perspective, PTC is recommended for pediatric strength and conditioning coaches because it produced comparable training effects as PTS on proxies of muscle power, muscle strength, speed, agility, static balance, and additional effects on dynamic balance.}, language = {en} } @article{LesinskiPrieskeHelmetal.2017, author = {Lesinski, Melanie and Prieske, Olaf and Helm, Norman and Granacher, Urs}, title = {Effects of Soccer Training on Anthropometry, Body Composition, and Physical Fitness during a Soccer Season in Female Elite Young Athletes: A Prospective Cohort Study}, series = {Frontiers in physiology}, volume = {8}, journal = {Frontiers in physiology}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-042X}, doi = {10.3389/fphys.2017.01093}, pages = {13}, year = {2017}, abstract = {The objectives of this study were to (i) describe soccer training (e.g., volume, types), anthropometry, body composition, and physical fitness and (0 compute associations between soccer training data and relative changes of anthropometry, body composition, and physical fitness during a soccer season in female elite young athletes. Seasonal training (i.e., day-to-day training volume/types) as well as variations in anthropometry (e.g., body height/mass), body composition (e.g., lean body/fat mass), and physical fitness (e.g., muscle strength/power, speed, balance) were collected from 17 female elite young soccer players (15.3 +/- 0.5 years) over the training periods (i.e., preparation, competition, transition) of a soccer season that resulted in the German championship title in under-17 female soccer. Training volume/types, anthropometrics, body composition, and physical fitness significantly varied over a soccer season. During the two preparation periods, higher volumes in resistance and endurance training were performed (2.00 <= d <= 18.15; p < 0.05), while higher sprint and tactical training volumes were applied during the two competition periods (2.22 <= d <= 11.18; p < 0.05). Body height and lean body mass increased over the season (2.50 <= d <= 3.39; p < 0.01). In terms of physical fitness, significant performance improvements were found over the soccer season in measures of balance, endurance, and sport-specific performance (2.52 <= d <= 3.95; p < 0.05). In contrast, no statistically significant changes were observed for measures of muscle power/endurance, speed, and change-of-direction speed. Of note, variables of muscle strength (i.e., leg extensors) significantly decreased (d = 2.39: p < 0.01) over the entire season. Our period specific sub analyses revealed significant performance improvements during the first round of the season for measures of muscle power/endurance, and balance (0.89 <= d <= 4.01; p < 0.05). Moreover, change-of-direction speed significantly declined after the first round of the season, i.e., transition period (d = 2.83; p < 0.01). Additionally, significant medium-to-large associations were observed between training and anthropometrics/body composition/physical fitness (-0.541 <= r <= 0.505). Soccer training and/or growth/maturation contributed to significant variations in anthropometry, body composition, and physical fitness outcomes throughout the different training periods over the course of a soccer season in female elite young soccer players. However, changes in components of fitness were inconsistent (e.g., power, speed, strength). Thus, training volume and/or types should be carefully considered in order to develop power-, speed- or strength-related fitness measures more efficiently throughout the soccer season.}, language = {en} } @article{GranacherBorde2017, author = {Granacher, Urs and Borde, Ron}, title = {Effects of Sport-Specific Training during the Early Stages of Long-Term Athlete Development on Physical Fitness, Body Composition, Cognitive, and Academic Performances}, series = {Frontiers in physiology}, volume = {8}, journal = {Frontiers in physiology}, publisher = {Frontiers}, address = {Lausanne}, issn = {1664-042X}, doi = {10.3389/fphys.2017.00810}, pages = {1 -- 11}, year = {2017}, abstract = {Introduction: Several sports demand an early start into long-term athlete development (LTAD) because peak performances are achieved at a relatively young age (e.g., gymnastics). However, the challenging combination of high training volumes and academic demands may impede youth athletes' cognitive and academic performances. Thus, the aims of this study were to examine the effects of a 1-year sport-specific training and/or physical education on physical fitness, body composition, cognitive and academic performances in youth athletes and their non-athletic peers. Methods: Overall, 45 prepubertal fourth graders from a German elite sport school were enrolled in this study. Participating children were either youth athletes from an elite sports class (n = 20, age 9.5 ± 0.5 years) or age-matched peers from a regular class (n = 25, age 9.6 ± 0.6 years). Over the 1-year intervention period, the elite sports class conducted physical education and sport-specific training (i.e., gymnastics, swimming, soccer, bicycle motocross [BMX]) during school time while the regular class attended physical education only. Of note, BMX is a specialized form of cycling that is performed on motocross tracks and affords high technical skills. Before and after intervention, tests were performed for the assessment of physical fitness (speed [20-m sprint], agility [star agility run], muscle power [standing long jump], flexibility [stand-and-reach], endurance [6-min-run], balance [single-leg stance]), body composition (e.g., muscle mass), cognitive (d2-test) and academic performance (reading [ELFE 1-6], writing [HSP 4-5], calculating [DEMAT 4]). In addition, grades in German, English, Mathematics, and physical education were documented. Results: At baseline, youth athletes showed better physical fitness performances (p < 0.05; d = 0.70-2.16), less relative body fat mass, more relative skeletal muscle mass (p < 0.01; d = 1.62-1.84), and similar cognitive and academic achievements compared to their non-athletic peers. Athletes' training volume amounted to 620 min/week over the 1-year period while their peers performed 155 min/week. After the intervention, significant differences were found in 6 out of 7 physical fitness tests (p < 0.05; d = 0.75-1.40) and in the physical education grades (p < 0.01; d = 2.36) in favor of the elite sports class. No significant between-group differences were found after the intervention in measures of body composition (p > 0.05; d = 0.66-0.67), cognition and academics (p > 0.05; d = 0.40-0.64). Our findings revealed no significant between-group differences in growth rate (deltas of pre-post-changes in body height and leg length). Discussion: Our results revealed that a school-based 1-year sport-specific training in combination with physical education improved physical fitness but did not negatively affect cognitive and academic performances of youth athletes compared to their non-athletic peers. It is concluded that sport-specific training in combination with physical education promotes youth athletes' physical fitness development during LTAD and does not impede their cognitive and academic development.}, 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} }