TY - JOUR A1 - Beurskens, Rainer A1 - Steinberg, Fabian A1 - Antoniewicz, Franziska A1 - Wolff, Wanja A1 - Granacher, Urs T1 - Neural Correlates of Dual-Task Walking BT - Effects of Cognitive versus Motor Interference in Young Adults JF - Neural plasticity N2 - 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. Y1 - 2016 U6 - https://doi.org/10.1155/2016/8032180 VL - 2016 SP - 1 EP - 9 PB - Hindawi CY - New York ER - TY - JOUR A1 - Negra, Yassine A1 - Chaabene, Helmi A1 - Hammami, Mehrez A1 - Hachana, Younes A1 - Granacher, Urs T1 - EFFECTS OF HIGH-VELOCITY RESISTANCE TRAINING ON ATHLETIC PERFORMANCE IN PREPUBERAL MALE SOCCER ATHLETES JF - Journal of strength and conditioning research : the research journal of the NSCA N2 - 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. KW - youth soccer KW - change of direction KW - jump performances KW - sprint Y1 - 2016 U6 - https://doi.org/10.1519/JSC.0000000000001433 SN - 1064-8011 SN - 1533-4287 VL - 30 SP - 3290 EP - 3297 PB - Wiley-Blackwell CY - Philadelphia ER - TY - JOUR A1 - Lesinski, Melanie A1 - Prieske, Olaf A1 - Demps, Marie A1 - Granacher, Urs T1 - Effects of fatigue and surface instability on neuromuscular performance during jumping JF - Der Schmerz : Organ der Deutschen Gesellschaft zum Studium des Schmerzes, der Österreichischen Schmerzgesellschaft und der Deutschen Interdisziplinären Vereinigung für Schmerztherapie N2 - 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. KW - Exhaustion KW - stretch-shortening cycle KW - jump height KW - EMG KW - athlete. Y1 - 2016 U6 - https://doi.org/10.1111/sms.12548 SN - 0905-7188 SN - 1600-0838 VL - 26 SP - 1140 EP - 1150 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Hammami, Raouf A1 - Granacher, Urs A1 - Makhlouf, Issam A1 - Behm, David George A1 - Chaouachi, Anis T1 - SEQUENCING EFFECTS OF BALANCE AND PLYOMETRIC TRAINING ON PHYSICAL PERFORMANCE IN YOUTH SOCCER ATHLETES JF - Journal of strength and conditioning research : the research journal of the NSCA N2 - 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. KW - children KW - adolescents KW - power KW - jumps KW - sprints Y1 - 2016 U6 - https://doi.org/10.1519/JSC.0000000000001425 SN - 1064-8011 SN - 1533-4287 VL - 30 SP - 3278 EP - 3289 PB - Elsevier CY - Philadelphia ER - TY - JOUR A1 - Hammami, Raouf A1 - Chaouachi, Anis A1 - Makhlouf, Issam A1 - Granacher, Urs A1 - Behm, David George T1 - Associations Between Balance and Muscle Strength, Power Performance in Male Youth Athletes of Different Maturity Status JF - Pediatric exercise science N2 - 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. KW - children KW - adolescents KW - training KW - peak height velocity KW - relationships Y1 - 2016 U6 - https://doi.org/10.1123/pes.2015-0231 SN - 0899-8493 SN - 1543-2920 VL - 28 SP - 521 EP - 534 PB - Human Kinetics Publ. CY - Champaign ER - TY - JOUR A1 - Beurskens, Rainer A1 - Mühlbauer, Thomas A1 - Grabow, Lena A1 - Kliegl, Reinhold A1 - Granacher, Urs T1 - Effects of Backpack Carriage on Dual-Task Performance in Children During Standing and Walking JF - Journal of motor behavior KW - attentional demand KW - cognitive performance KW - gait analysis KW - load carriage KW - postural control Y1 - 2016 U6 - https://doi.org/10.1080/00222895.2016.1152137 SN - 0022-2895 SN - 1940-1027 VL - 48 SP - 500 EP - 508 PB - Wiley-VCH CY - Abingdon ER - TY - JOUR A1 - Beurskens, Rainer A1 - Haeger, Matthias A1 - Kliegl, Reinhold A1 - Roecker, Kai A1 - Granacher, Urs T1 - Postural Control in Dual-Task Situations BT - Does Whole-Body Fatigue Matter? JF - PLoS one N2 - 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. Y1 - 2016 U6 - https://doi.org/10.1371/journal.pone.0147392 SN - 1932-6203 VL - 11 IS - 1 SP - 1 EP - 15 PB - PLoS CY - Lawrence, Kan. ER - TY - JOUR A1 - Beurskens, Rainer A1 - Haeger, Matthias A1 - Kliegl, Reinhold A1 - Roecker, Kai A1 - Granacher, Urs T1 - Postural Control in Dual-Task Situations: Does Whole-Body Fatigue Matter? JF - PLoS one N2 - 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. Y1 - 2016 U6 - https://doi.org/10.1371/journal.pone.0147392 SN - 1932-6203 VL - 11 SP - 1379 EP - 1384 PB - PLoS CY - San Fransisco ER - TY - JOUR A1 - Beurskens, Rainer A1 - Steinberg, Fabian A1 - Antoniewicz, Franziska A1 - Wolff, Wanja A1 - Granacher, Urs T1 - Neural Correlates of Dual-Task Walking: Effects of Cognitive versus Motor Interference in Young Adults JF - Neural plasticity N2 - 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. Y1 - 2016 U6 - https://doi.org/10.1155/2016/8032180 SN - 2090-5904 SN - 1687-5443 PB - Hindawi CY - London ER - TY - JOUR A1 - Wallenta, Christopher A1 - Granacher, Urs A1 - Lesinski, Melanie A1 - Schuenemann, C. A1 - Mühlbauer, Thomas T1 - Effects of Complex Versus Block Strength Training on the Athletic Performance of Elite Youth Soccer Players JF - Sportverletzung, Sportschaden : Grundlagen, Prävention, Rehabilitation N2 - Hintergrund: Kraft und Schnelligkeit stellen bedeutsame leistungsdeterminierende Faktoren im Fußball dar. Durch Komplextraining (Kombination aus Kraft- und plyometrischen Übungen in einer Trainingseinheit) lassen sich Kraft- und Schnelligkeitswerte von Athleten steigern. Unklar ist jedoch, ob ein Komplextraining (KT) gegenüber einem herkömmlichen blockweisen Krafttraining (BT) zu größeren sportmotorischen Leistungssteigerungen führt. Das Ziel der Studie war es, die Effekte von KT versus BT auf Variablen der Kraft, Schnelligkeit und Gewandtheit von Nachwuchsleistungsfußballern zu untersuchen. Methode: Zusätzlich zum regulären Fußballtraining (ca. 6 × pro Woche, je 60 – 90 min.) führten 18 männliche Nachwuchsleistungsfußballer über 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) durchgeführt. 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: ≥ 80 %) Trainingsmaßnahmen in Ergänzung zum regulären Fußballtraining. Die statistische Analyse ergab signifikante Verbesserungen vom Prä- zum Posttest für die KT-Gruppe im EWM (p = 0,043) und im HSS (p = 0,046) sowie für die BT-Gruppe in der Sprintzeit über 5 m (p = 0,039) und 10 m (p = 0,026). Zudem zeigten sich für beide Gruppen signifikante Verbesserungen im T-Test (KT: p = 0,046; BT: p = 0,027). Der Gruppenvergleich (KT vs. BT) über die Zeit (Post- minus Prätest) offenbarte keine bedeutsamen Unterschiede. Schlussfolgerung: Sowohl sechswöchiges KT als auch BT führten zu signifikanten Verbesserungen sportmotorischer Leistungen bei Nachwuchsleistungsfußballern. Allerdings konnten keine zusätzlich leistungssteigernden Effekte von KT im Vergleich zu BT ermittelt werden. In zukünftigen Studien sollte geprüft werden, ob die beobachteten testspezifischen Veränderungen, d. h. Verbesserung der Kraft/Sprungkraft in der KT-Gruppe und Verbesserung der Schnelligkeit in der BT-Gruppe der gewählten Übungsanordnung 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. KW - strength training KW - jump/sprint exercises KW - youth athletes Y1 - 2016 U6 - https://doi.org/10.1055/s-0041-106949 SN - 0932-0555 SN - 1439-1236 VL - 30 SP - 31 EP - 37 PB - Thieme CY - Stuttgart ER - TY - JOUR A1 - Lacroix, Andre A1 - Kressig, Reto W. A1 - Mühlbauer, Thomas A1 - Gschwind, Yves J. A1 - Pfenninger, Barbara A1 - Bruegger, Othmar A1 - Granacher, Urs T1 - 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 JF - Gerontology N2 - 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 KW - Sensorimotor training KW - Resistance training KW - Gym-based/home-based training KW - Detraining KW - Seniors Y1 - 2016 U6 - https://doi.org/10.1159/000442087 SN - 0304-324X SN - 1423-0003 VL - 62 SP - 275 EP - 288 PB - Karger CY - Basel ER - TY - JOUR A1 - Kuemmel, Jakob A1 - Bergmann, Julian A1 - Prieske, Olaf A1 - Kramer, Andreas A1 - Granacher, Urs A1 - Gruber, Markus T1 - Effects of conditioning hops on drop jump and sprint performance: a randomized crossover pilot study in elite athletes JF - BMC sports science, medicine & rehabilitation N2 - 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. KW - Post-activation potentiation KW - Performance gains KW - Reactive movement KW - Plyometric exercise Y1 - 2016 U6 - https://doi.org/10.1186/s13102-016-0027-z SN - 2052-1847 VL - 8 PB - BioMed Central CY - London ER - TY - JOUR A1 - Prieske, Olaf A1 - Mühlbauer, Thomas A1 - Borde, Ron A1 - Gube, M. A1 - Bruhn, S. A1 - Behm, David George A1 - Granacher, Urs T1 - Neuromuscular and athletic performance following core strength training in elite youth soccer: Role of instability JF - Learning and individual differences N2 - 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. KW - Elite sports KW - jumping KW - agility KW - sprint KW - ball speed KW - electromyography Y1 - 2016 U6 - https://doi.org/10.1111/sms.12403 SN - 0905-7188 SN - 1600-0838 VL - 26 SP - 48 EP - 56 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Beijersbergen, Chantal M. I. A1 - Hortobagyi, Tibor A1 - Beurskens, Rainer A1 - Lenzen-Grossimlinghaus, Romana A1 - Gabler, Martijn A1 - Granacher, Urs T1 - 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) JF - Gerontology N2 - 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 KW - Aging KW - Walking speed KW - Exercise KW - Muscle power KW - Gait kinematics KW - Gait kinetics Y1 - 2016 U6 - https://doi.org/10.1159/000444752 SN - 0304-324X SN - 1423-0003 VL - 62 SP - 597 EP - 603 PB - Karger CY - Basel ER -