TY - JOUR A1 - Lesinski, Melanie A1 - Prieske, Olaf A1 - Beurskens, Rainer A1 - Behm, David George A1 - Granacher, Urs T1 - Effects of Drop-height and Surface Instability on Jump Performance and Knee Kinematics JF - International journal of sports medicine N2 - The purpose of this study was to examine the combined effects of drop-height and surface condition on drop jump (DJ) performance and knee joint kinematics. DJ performance, sagittal and frontal plane knee joint kinematics were measured in jump experienced young male and female adults during DJs on stable, unstable and highly unstable surfaces using different drop-heights (20, 40, 60 cm). Findings revealed impaired DJ performance (Δ5–16%; p<0.05; 1.43≤d≤2.82), reduced knee valgus motion (Δ33–52%; p<0.001; 2.70≤d≤3.59), and larger maximum knee flexion angles (Δ13–19%; p<0.01; 1.74≤d≤1.75) when using higher (60 cm) compared to lower drop-heights (≤40 cm). Further, lower knee flexion angles and velocity were found (Δ8-16%; p<0.01; 1.49≤d≤2.38) with increasing surface instability. When performing DJs from high (60 cm) compared to moderate drop-heights (40 cm) on highly unstable surfaces, higher knee flexion velocity and maximum knee valgus angles were found (Δ15–19%; p<0.01; 1.50≤d≤1.53). No significant main and/or interaction effects were observed for the factor sex. In conclusion, knee motion strategies were modified by the factors ‘drop-height’ and/or ‘surface instability’. The combination of high drop-heights (>40 cm) together with highly unstable surfaces should be used cautiously during plyometrics because this may increase the risk of injury due to higher knee valgus stress. KW - drop jump KW - knee flexion angle KW - knee valgus angle KW - knee valgus motion Y1 - 2017 U6 - https://doi.org/10.1055/s-0043-117610 SN - 0172-4622 SN - 1439-3964 VL - 39 IS - 1 SP - 50 EP - 57 PB - Thieme CY - Stuttgart ER - TY - GEN A1 - Müller, Steffen A1 - Müller, Juliane A1 - Stoll, Josefine A1 - Prieske, Olaf A1 - Cassel, Michael A1 - Mayer, Frank T1 - Incidence of back pain in adolescent athletes BT - a prospective study N2 - Background Recently, the incidence rate of back pain (BP) in adolescents has been reported at 21%. However, the development of BP in adolescent athletes is unclear. Hence, the purpose of this study was to examine the incidence of BP in young elite athletes in relation to gender and type of sport practiced. Methods Subjective BP was assessed in 321 elite adolescent athletes (m/f 57%/43%; 13.2 ± 1.4 years; 163.4 ± 11.4 cm; 52.6 ± 12.6 kg; 5.0 ± 2.6 training yrs; 7.6 ± 5.3 training h/week). Initially, all athletes were free of pain. The main outcome criterion was the incidence of back pain [%] analyzed in terms of pain development from the first measurement day (M1) to the second measurement day (M2) after 2.0 ± 1.0 year. Participants were classified into athletes who developed back pain (BPD) and athletes who did not develop back pain (nBPD). BP (acute or within the last 7 days) was assessed with a 5-step face scale (face 1–2 = no pain; face 3–5 = pain). BPD included all athletes who reported faces 1 and 2 at M1 and faces 3 to 5 at M2. nBPD were all athletes who reported face 1 or 2 at both M1 and M2. Data was analyzed descriptively. Additionally, a Chi2 test was used to analyze gender- and sport-specific differences (p = 0.05). Results Thirty-two athletes were categorized as BPD (10%). The gender difference was 5% (m/f: 12%/7%) but did not show statistical significance (p = 0.15). The incidence of BP ranged between 6 and 15% for the different sport categories. Game sports (15%) showed the highest, and explosive strength sports (6%) the lowest incidence. Anthropometrics or training characteristics did not significantly influence BPD (p = 0.14 gender to p = 0.90 sports; r2 = 0.0825). Conclusions BP incidence was lower in adolescent athletes compared to young non-athletes and even to the general adult population. Consequently, it can be concluded that high-performance sports do not lead to an additional increase in back pain incidence during early adolescence. Nevertheless, back pain prevention programs should be implemented into daily training routines for sport categories identified as showing high incidence rates. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 310 KW - Injury KW - Pain occurrence KW - Training volume KW - Young athletes Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-101874 ER - TY - JOUR A1 - Granacher, Urs A1 - Lesinski, Melanie A1 - Buesch, Dirk A1 - Mühlbauer, Thomas A1 - Prieske, Olaf A1 - Puta, Christian A1 - Gollhofer, Albert A1 - Behm, David George T1 - Effects of Resistance Training in Youth Athletes on Muscular Fitness and Athletic Performance: A Conceptual Model for Long-Term Athlete Development JF - Frontiers in physiology N2 - During the stages of long-term athlete development (LTAD), resistance training (RT) is an important means for (i) stimulating athletic development, (ii) tolerating the demands of long-term training and competition, and (iii) inducing long-term health promoting effects that are robust over time and track into adulthood. However, there is a gap in the literature with regards to optimal RT methods during LTAD and how RT is linked to biological age. Thus, the aims of this scoping review were (i) to describe and discuss the effects of RT on muscular fitness and athletic performance in youth athletes, (ii) to introduce a conceptual model on how to appropriately implement different types of RT within LTAD stages, and (iii) to identify research gaps from the existing literature by deducing implications for future research. In general, RT produced small -to -moderate effects on muscular fitness and athletic performance in youth athletes with muscular strength showing the largest improvement. Free weight, complex, and plyometric training appear to be well -suited to improve muscular fitness and athletic performance. In addition, balance training appears to be an important preparatory (facilitating) training program during all stages of LTAD but particularly during the early stages. As youth athletes become more mature, specificity, and intensity of RT methods increase. This scoping review identified research gaps that are summarized in the following and that should be addressed in future studies: (i) to elucidate the influence of gender and biological age on the adaptive potential following RT in youth athletes (especially in females), (ii) to describe RT protocols in more detail (i.e., always report stress and strain based parameters), and (iii) to examine neuromuscular and tendomuscular adaptations following RT in youth athletes. KW - weight lifting KW - children KW - adolescents KW - physical fitness KW - muscle strength KW - muscle power KW - muscular endurance Y1 - 2016 U6 - https://doi.org/10.3389/fphys.2016.00164 SN - 1664-042X VL - 7 PB - Frontiers Research Foundation CY - Lausanne ER - TY - GEN A1 - Granacher, Urs A1 - Schellbach, Jörg A1 - Klein, Katja A1 - Prieske, Olaf A1 - Baeyens, Jean-Pierre A1 - Mühlbauer, Thomas T1 - Effects of core strength training using stable versus unstable surfaces on physical fitness in adolescents BT - a randomized controlled trial N2 - 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. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 297 KW - Resistance training KW - Trunk muscle strength KW - Physical fitness Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-93490 ER - TY - JOUR A1 - Lesinski, Melanie A1 - Prieske, Olaf A1 - Granacher, Urs T1 - Effects and dose-response relationships of resistance training on physical performance in youth athletes: a systematic review and meta-analysis JF - British journal of sports medicine : the journal of sport and exercise medicine N2 - Objectives To quantify age, sex, sport and training type-specific effects of resistance training on physical performance, and to characterise dose-response relationships of resistance training parameters that could maximise gains in physical performance in youth athletes. Design Systematic review and meta-analysis of intervention studies. Data sources Studies were identified by systematic literature search in the databases PubMed and Web of Science (1985-2015). Weighted mean standardised mean differences (SMDwm) were calculated using random-effects models. Eligibility criteria for selecting studies Only studies with an active control group were included if these investigated the effects of resistance training in youth athletes (6-18 years) and tested at least one physical performance measure. Results 43 studies met the inclusion criteria. Our analyses revealed moderate effects of resistance training on muscle strength and vertical jump performance (SMDwm 0.8-1.09), and small effects on linear sprint, agility and sport-specific performance (SMDwm 0.58-0.75). Effects were moderated by sex and resistance training type. Independently computed dose-response relationships for resistance training parameters revealed that a training period of >23 weeks, 5 sets/exercise, 6-8 repetitions/set, a training intensity of 80-89% of 1 repetition maximum (RM), and 3-4 min rest between sets were most effective to improve muscle strength (SMDwm 2.09-3.40). Summary/conclusions Resistance training is an effective method to enhance muscle strength and jump performance in youth athletes, moderated by sex and resistance training type. Dose-response relationships for key training parameters indicate that youth coaches should primarily implement resistance training programmes with fewer repetitions and higher intensities to improve physical performance measures of youth athletes. Y1 - 2016 U6 - https://doi.org/10.1136/bjsports-2015-095497 SN - 0306-3674 SN - 1473-0480 VL - 50 SP - 781 EP - 795 PB - BMJ Publishing Group 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 - Prieske, Olaf A1 - Mühlbauer, Thomas A1 - Granacher, Urs T1 - The Role of Trunk Muscle Strength for Physical Fitness and Athletic Performance in Trained Individuals: A Systematic Review and Meta-Analysis JF - Sports medicine N2 - Background The importance of trunk muscle strength (TMS) for physical fitness and athletic performance has been demonstrated by studies reporting significant correlations between those capacities. However, evidence-based knowledge regarding the magnitude of correlations between TMS and proxies of physical fitness and athletic performance as well as potential effects of core strength training (CST) on TMS, physical fitness and athletic performance variables is currently lacking for trained individuals. Objective The aims of this systematic review and meta-analysis were to quantify associations between variables of TMS, physical fitness and athletic performance and effects of CST on these measures in healthy trained individuals. Data Sources PubMed, Web of Science, and SPORTDiscus were systematically screened from January 1984 to March 2015. Study Eligibility Criteria Studies were included that investigated healthy trained individuals aged 16-44 years and tested at least one measure of TMS, muscle strength, muscle power, balance, and/or athletic performance. Results Small-sized relationships of TMS with physical performance measures (-0.05 <= r <= 0.18) were found in 15 correlation studies. Sixteen intervention studies revealed large effects of CST on measures of TMS (SMD = 1.07) but small-to-medium-sized effects on proxies of physical performance (0 <= SMD <= 0.71) compared with no training or regular training only. The methodological quality of CST studies was low (median PEDro score = 4). Conclusions Our findings indicate that TMS plays only a minor role for physical fitness and athletic performance in trained individuals. In fact, CST appears to be an effective means to increase TMS and was associated with only limited gains in physical fitness and athletic performance measures when compared with no or only regular training. Y1 - 2016 U6 - https://doi.org/10.1007/s40279-015-0426-4 SN - 0112-1642 SN - 1179-2035 VL - 46 SP - 401 EP - 419 PB - Springer CY - Northcote 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 - GEN A1 - Granacher, Urs A1 - Lesinski, Melanie A1 - Büsch, Dirk A1 - Mühlbauer, Thomas A1 - Prieske, Olaf A1 - Puta, Christian A1 - Gollhofer, Albert A1 - Behm, David George T1 - Effects of resistance training in youth athletes on muscular fitness and athletic performance BT - a conceptual model for long-term athlete development T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - During the stages of long-term athlete development (LTAD), resistance training (RT) is an important means for (i) stimulating athletic development, (ii) tolerating the demands of long-term training and competition, and (iii) inducing long-term health promoting effects that are robust over time and track into adulthood. However, there is a gap in the literature with regards to optimal RT methods during LTAD and how RT is linked to biological age. Thus, the aims of this scoping review were (i) to describe and discuss the effects of RT on muscular fitness and athletic performance in youth athletes, (ii) to introduce a conceptual model on how to appropriately implement different types of RT within LTAD stages, and (iii) to identify research gaps from the existing literature by deducing implications for future research. In general, RT produced small -to -moderate effects on muscular fitness and athletic performance in youth athletes with muscular strength showing the largest improvement. Free weight, complex, and plyometric training appear to be well -suited to improve muscular fitness and athletic performance. In addition, balance training appears to be an important preparatory (facilitating) training program during all stages of LTAD but particularly during the early stages. As youth athletes become more mature, specificity, and intensity of RT methods increase. This scoping review identified research gaps that are summarized in the following and that should be addressed in future studies: (i) to elucidate the influence of gender and biological age on the adaptive potential following RT in youth athletes (especially in females), (ii) to describe RT protocols in more detail (i.e., always report stress and strain based parameters), and (iii) to examine neuromuscular and tendomuscular adaptations following RT in youth athletes. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 429 KW - weight lifting KW - children KW - adolescents KW - physical fitness KW - muscle strength KW - muscle power KW - muscular endurance Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-406574 IS - 429 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 - Müller, Steffen A1 - Müller, Juliane A1 - Stoll, Josefine A1 - Prieske, Olaf A1 - Cassel, Michael A1 - Mayer, Frank T1 - Incidence of back pain in adolescent athletes BT - a prospective study JF - BMC sports science, medicine & rehabilitation N2 - Background Recently, the incidence rate of back pain (BP) in adolescents has been reported at 21%. However, the development of BP in adolescent athletes is unclear. Hence, the purpose of this study was to examine the incidence of BP in young elite athletes in relation to gender and type of sport practiced. Methods Subjective BP was assessed in 321 elite adolescent athletes (m/f 57%/43%; 13.2 ± 1.4 years; 163.4 ± 11.4 cm; 52.6 ± 12.6 kg; 5.0 ± 2.6 training yrs; 7.6 ± 5.3 training h/week). Initially, all athletes were free of pain. The main outcome criterion was the incidence of back pain [%] analyzed in terms of pain development from the first measurement day (M1) to the second measurement day (M2) after 2.0 ± 1.0 year. Participants were classified into athletes who developed back pain (BPD) and athletes who did not develop back pain (nBPD). BP (acute or within the last 7 days) was assessed with a 5-step face scale (face 1–2 = no pain; face 3–5 = pain). BPD included all athletes who reported faces 1 and 2 at M1 and faces 3 to 5 at M2. nBPD were all athletes who reported face 1 or 2 at both M1 and M2. Data was analyzed descriptively. Additionally, a Chi2 test was used to analyze gender- and sport-specific differences (p = 0.05). Results Thirty-two athletes were categorized as BPD (10%). The gender difference was 5% (m/f: 12%/7%) but did not show statistical significance (p = 0.15). The incidence of BP ranged between 6 and 15% for the different sport categories. Game sports (15%) showed the highest, and explosive strength sports (6%) the lowest incidence. Anthropometrics or training characteristics did not significantly influence BPD (p = 0.14 gender to p = 0.90 sports; r2 = 0.0825). Conclusions BP incidence was lower in adolescent athletes compared to young non-athletes and even to the general adult population. Consequently, it can be concluded that high-performance sports do not lead to an additional increase in back pain incidence during early adolescence. Nevertheless, back pain prevention programs should be implemented into daily training routines for sport categories identified as showing high incidence rates. KW - Pain occurrence KW - Young athletes KW - Injury KW - Training volume Y1 - 2016 U6 - https://doi.org/10.1186/s13102-016-0064-7 SN - 2052-1847 VL - 8 PB - BioMed Central CY - London ER - TY - THES A1 - Prieske, Olaf T1 - The role of surface condition in athletic performance T1 - Die Bedeutung des Untergrundes für die sportmotorische Leistung N2 - During the last two decades, instability training devices have become a popular means in athletic training and rehabilitation of mimicking unstable surfaces during movements like vertical jumps. Of note, under unstable conditions, trunk muscles seem to have a stabilizing function during exercise to facilitate the transfer of torques and angular momentum between the lower and upper extremities. The present thesis addresses the acute effects of surface instability on performance during jump-landing tasks. Additionally, the long-term effects (i.e., training) of surface instability were examined with a focus on the role of the trunk in athletic performance/physical fitness. Healthy adolescent, and young adult subjects participated in three cross-sectional and one longitudinal study, respectively. Performance in jump-landing tasks on stable and unstable surfaces was assessed by means of a ground reaction force plate. Trunk muscle strength (TMS) was determined using an isokinetic device or the Bourban TMS test. Physical fitness was quantified by standing long jump, sprint, stand-and-reach, jumping sideways, Emery balance, and Y balance test on stable surfaces. In addition, activity of selected trunk and leg muscles and lower limb kinematics were recorded during jump-landing tasks. When performing jump-landing tasks on unstable compared to stable surfaces, jump performance and leg muscle activity were significantly lower. Moreover, significantly smaller knee flexion angles and higher knee valgus angles were observed when jumping and landing on unstable compared to stable conditions and in women compared to men. Significant but small associations were found between behavioral and neuromuscular data, irrespective of surface condition. Core strength training on stable as well as on unstable surfaces significantly improved TMS, balance and coordination. The findings of the present thesis imply that stable rather than unstable surfaces provide sufficient training stimuli during jump exercises (i.e., plyometrics). Additionally, knee motion strategy during plyometrics appears to be modified by surface instability and sex. Of note, irrespective of surface condition, trunk muscles only play a minor role for leg muscle performance/activity during jump exercises. Moreover, when implemented in strength training programs (i.e., core strength training), there is no advantage in using instability training devices compared to stable surfaces in terms of enhancement of athletic performance. N2 - Instabile Trainingsgeräte sind etablierte Bestandteile im sportlichen Training und in der Rehabilitation, um instabile Untergründe während verschiedener alltags- und sportartspezifischer Bewegungen zu simulieren. Dabei scheint der Rumpfmuskulatur insbesondere unter instabilen Bedingungen eine wichtige Rolle zur Stabilisierung zu zukommen. Die vorliegende Arbeit widmet sich den Akuteffekten von Untergrundinstabilität auf die Leistung bei Sprüngen und Landungen. Zudem wurden Langzeiteffekte von Untergrundinstabilität auf die Bedeutung des Rumpfes für die sportliche/sportmotorische Leistung untersucht. Gesunde Jugendliche und junge Erwachsene nahmen an drei Quer- bzw. einer Längsschnittstudie teil. Die Leistung der Sprung-Lande-Aufgaben auf stabilen und instabilen Untergründen wurde mittels Kraftmessplatte erfasst. Die Rumpfkraft wurde mit einem Isokineten oder dem Bourban-Rumpfkraft-Test gemessen. Die Ermittlung sportmotorischer Leistungen erfolgte durch Standweitsprung-, Sprint-, Rumvorbeuge-, Seitsprung-, Emery- und Y-Balance-Test auf stabilen Untergründen. Zudem wurde die Aktivität ausgewählter Rumpf- und Beinmuskeln und Beinkinematik während der Sprung-Lande-Aufgaben erfasst. Sprung-Lande-Aufgaben auf instabilen im Vergleich zu stabilen Unterlagen führten zu signifikant geringeren Sprungleistungen und Beinmuskelaktivitäten. Dabei wurden die Kniegelenke unter instabilen im Vergleich zu stabilen Bedingungen stärker extendiert und valgisiert. Dies gilt auch für Frauen im Vergleich zu Männern während des Springens und Landens. Zusammenhänge zwischen den Verhaltens- und neuromuskulären Daten unabhängig vom Untergrund sind als gering einzuschätzen sind. Ein Rumpfkrafttraining auf stabilen sowie auf instabilen Untergründen verbesserte die Rumpfkraft, das Gleichgewicht und die Koordination. Zusammenfassend zeigen die Ergebnisse, dass stabile gegenüber instabilen Unterlagen bessere Voraussetzungen bei Sprungübungen zur Steigerung der Sprungleistung im Training schaffen. Zudem scheint die biomechanische Kontrollstrategie des Kniegelenks bei Sprüngen durch den Untergrund und das Geschlecht modifiziert. Dabei ist zu erwähnen, dass für den Leistungsvollzug der unteren Extremitäten beim Springen der Rumpf unabhängig von den Untergrundbedingungen nur eine kleine Rolle zu spielen scheint. Darüber hinaus zeigen instabile gegenüber stabilen Untergründen in einem Rumpfkrafttraining keinen Vorteil hinsichtlich der Steigerung sportlicher Leistungen. KW - biomechanics KW - jump-landing tasks KW - trunk muscle strength KW - instability KW - injury prevention KW - Biomechanik KW - Sprung-Lande-Aufgaben KW - Rumpfmuskelkraft KW - Instabilität KW - Verletzungsprävention Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-80503 ER - TY - JOUR A1 - Prieske, Olaf A1 - Mühlbauer, Thomas A1 - Krüger, Tom A1 - Kibele, A. A1 - Behm, David George A1 - Granacher, Urs T1 - Sex-Specific effects of surface instability on drop jump and landing biomechanics JF - International journal of sports medicine N2 - 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. KW - stretch-shortening cycle KW - ground reaction force KW - knee joint angle KW - injury risk Y1 - 2015 U6 - https://doi.org/10.1055/s-0034-1384549 SN - 0172-4622 SN - 1439-3964 VL - 36 IS - 1 SP - 75 EP - 81 PB - Thieme CY - Stuttgart ER - TY - JOUR A1 - Granacher, Urs A1 - Prieske, Olaf A1 - Majewski, M. A1 - Büsch, Dirk A1 - Mühlbauer, Thomas T1 - The Role of Instability with Plyometric Training in Sub-elite Adolescent Soccer Players JF - International journal of sports medicine N2 - 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. KW - strength KW - jump KW - speed KW - agility KW - balance Y1 - 2015 U6 - https://doi.org/10.1055/s-0034-1395519 SN - 0172-4622 SN - 1439-3964 VL - 36 IS - 5 SP - 386 EP - 394 PB - Thieme CY - Stuttgart ER - TY - JOUR A1 - Prieske, Olaf A1 - Mühlbauer, Thomas A1 - Krüger, Tom A1 - Kibele, Armin A1 - Behm, David George A1 - Granacher, Urs T1 - Role of the trunk during drop jumps on stable and unstable surfaces JF - European journal of applied physiology N2 - 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. KW - Core stability KW - Jump height KW - Knee valgus motion KW - Ground reaction force KW - Stretch-shortening cycle KW - Electromyography Y1 - 2015 U6 - https://doi.org/10.1007/s00421-014-3004-9 SN - 1439-6319 SN - 1439-6327 VL - 115 IS - 1 SP - 139 EP - 146 PB - Springer CY - New York ER - TY - JOUR A1 - Prieske, Olaf A1 - Wick, Ditmar A1 - Granacher, Urs T1 - Intrasession and intersession reliability in maximal and explosive isometric torque production of the elbow flexors JF - Journal of strength and conditioning research : the research journal of the NSCA N2 - 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. KW - maximal isometric contraction KW - explosive force production KW - electromyography KW - test-retest reliability Y1 - 2014 SN - 1064-8011 SN - 1533-4287 VL - 28 IS - 6 SP - 1771 EP - 1777 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - JOUR A1 - Granacher, Urs A1 - Schellbach, Jörg A1 - Klein, Katja A1 - Prieske, Olaf A1 - Baeyens, Jean-Pierre A1 - Mühlbauer, Thomas T1 - Effects of core strength training using stable versus unstable surfaces on physical fitness in adolescents BT - a randomized controlled trial JF - BMC sports science, medicine & rehabilitation N2 - 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. KW - Resistance training KW - Trunk muscle strength KW - Physical fitness Y1 - 2014 U6 - https://doi.org/10.1186/2052-1847-6-40 SN - 2052-1847 VL - 6 PB - BioMed Central CY - London ER - TY - JOUR A1 - Prieske, Olaf A1 - Mühlbauer, Thomas A1 - Müller, Steffen A1 - Krüger, Tom A1 - Kibele, Armin A1 - Behm, David George A1 - Granacher, Urs T1 - Effects of surface instability on neuromuscular performance during drop jumps and landings JF - European journal of applied physiology N2 - 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. KW - Stretch-shortening cycle KW - Trunk muscle strength KW - Jump height KW - Electromyography Y1 - 2013 U6 - https://doi.org/10.1007/s00421-013-2724-6 SN - 1439-6319 SN - 1439-6327 VL - 113 IS - 12 SP - 2943 EP - 2951 PB - Springer CY - New York ER -