@article{LesinskiPrieskeChaabeneetal.2021, author = {Lesinski, Melanie and Prieske, Olaf and Chaabene, Helmi and Granacher, Urs}, title = {Seasonal effects of strength endurance vs. power training in young female soccer athletes}, series = {Journal of strength and conditioning research : the research journal of the NSCA}, volume = {35}, journal = {Journal of strength and conditioning research : the research journal of the NSCA}, number = {Supplement 12}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia}, issn = {1064-8011}, doi = {10.1519/JSC.0000000000003564}, pages = {S90 -- S96}, year = {2021}, abstract = {Lesinski, M, Prieske, O, Chaabene, H, and Granacher, U. Seasonal effects of strength endurance vs. power training in young female soccer athletes. J Strength Cond Res 35(12S): S90-S96, 2021-This study examined the seasonal effects of strength endurance training (SET) vs. power training (PT) on physical fitness and body composition in young female soccer players. Thirty-six young female elite soccer players (15 +/- 1 years; maturity offset +3 +/- 1 years) were allocated to progressive SET (n = 19) or PT (n = 17). Over the course of one soccer season, SET performed slow movement velocity, moderate intensity (50-60\% of the 1 repetition maximum [1RM]; 20-40 repetitions) strength exercises while PT performed moderate-to-high intensity (50-95\% of the 1RM; 3-8 repetitions), high movement velocity strength exercises (2 sessions center dot wk(-1)). Before and after training, tests were performed for the assessment of muscle strength (1RM leg press), jump performance (countermovement jump [CMJ], drop jump [DJ]), muscular endurance (ventral Bourban test), linear speed (10 m, 20 m), change-of-direction (CoD) speed (T-test), dynamic balance (Y-balance test), sport-specific performance (kicking velocity), and body composition (lean body mass and fat mass). An analysis of covariance was used to test for between-group differences at post-test with baseline values as covariate. No significant between-group differences were observed in terms of total training volume over the respective soccer seasons (p = 0.069; d = 0.68). At post-test, SET showed significantly better ventral Bourban and T-test performances (d = 1.28-2.28; p = 0.000-0.001) compared with PT. However, PT resulted in significantly better 1RM leg press, DJ, 10-m, and 20-m sprint performances (d = 0.85-1.44; p = 0.000-0.026). No significant between-group differences were observed at post-test for CMJ, Y-balance test, kicking performance, and body composition (d = 0.20-0.74, p = 0.051-0.594). Our findings are mainly in accordance with the principle of training specificity. Both SET and PT are recommended to be implemented in young female elite soccer players according to the respective training period.}, language = {en} } @misc{ChaabeneLesinskiBehmetal.2020, author = {Chaabene, Helmi and Lesinski, Melanie and Behm, David George and Granacher, Urs}, title = {Performance- and healthrelated benefits of youth resistance training}, series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {3}, issn = {1866-8364}, doi = {10.25932/publishup-52691}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-526912}, pages = {12}, year = {2020}, abstract = {There is ample evidence that youth resistance training (RT) is safe, joyful, and effective for different markers of performance (e.g., muscle strength, power, linear sprint speed) and health (e.g., injury prevention). Accordingly, the first aim of this narrative review is to present and discuss the relevance of muscle strength for youth physical development. The second purpose is to report evidence on the effectiveness of RT on muscular fitness (muscle strength, power, muscle endurance), on movement skill performance and injury prevention in youth. There is evidence that RT is effective in enhancing measures of muscle fitness in children and adolescents, irrespective of sex. Additionally, numerous studies indicate that RT has positive effects on fundamental movement skills (e.g., jumping, running, throwing) in youth regardless of age, maturity, training status, and sex. Further, irrespective of age, sex, and training status, regular exposure to RT (e.g., plyometric training) decreases the risk of sustaining injuries in youth. This implies that RT should be a meaningful element of youths' exercise programming. This has been acknowledged by global (e.g., World Health Organization) and national (e.g., National Strength and Conditioning Association) health- and performance-related organizations which is why they recommended to perform RT as an integral part of weekly exercise programs to promote muscular strength, fundamental movement skills, and to resist injuries in youth.}, language = {en} } @article{LesinskiHerzSchmelcheretal.2020, author = {Lesinski, Melanie and Herz, Michael and Schmelcher, Alina and Granacher, Urs}, title = {Effects of resistance training on physical fitness in healthy children and adolescents}, series = {Sports medicine}, volume = {50}, journal = {Sports medicine}, number = {11}, publisher = {Springer}, address = {Northcote}, issn = {0112-1642}, doi = {10.1007/s40279-020-01327-3}, pages = {1901 -- 1928}, year = {2020}, abstract = {Background Over the past decades, an exponential growth has occurred with regards to the number of scientific publications including meta-analyses on youth resistance training (RT). Accordingly, it is timely to summarize findings from meta-analyses in the form of an umbrella review. Objectives To systematically review and summarise the findings of published meta-analyses that investigated the effects of RT on physical fitness in children and adolescents. Design Systematic umbrella review of meta-analyses. Data Sources Meta-analyses were identified using systematic literature searches in the databases PubMed, Web of Science, and Cochrane Library. Eligibility Criteria for Selecting Meta-analyses Meta-analyses that examined the effects of RT on physical fitness (e.g., muscle strength, muscle power) in healthy youth (<= 18 years). Results Fourteen meta-analyses were included in this umbrella review. Eleven of these meta-analyses reported between-subject effect sizes which are important to eliminate bias due to growth and maturation. RT produced medium-to-large effects on muscle strength, small-to-large effects on muscle power, small-to-medium effects on linear sprint, a medium effect on agility/change-of-direction speed, small-to-large effects on throwing performance, and a medium effect on sport-specific enhancement. There were few consistent moderating effects of maturation, age, sex, expertise level, or RT type on muscle strength and muscle power across the included meta-analyses. The analysed meta-analyses showed low-to-moderate methodological quality (AMSTAR2) as well as presented evidence of low-to-very low quality (GRADE). Conclusion This umbrella review proved the effectiveness of RT in youth on a high evidence level. The magnitude of effects varies according to the respective outcome measure and it appears to follow the principle of training specificity. Larger effect sizes were found for strength-related outcome measures. Future studies should consistently report data on participants' maturational status. More research is needed with prepubertal children and girls, irrespective of their maturational status.}, language = {en} } @article{ThielePrieskeLesinskietal.2020, author = {Thiele, Dirk and Prieske, Olaf and Lesinski, Melanie and Granacher, Urs}, title = {Effects of Equal Volume Heavy-Resistance Strength Training Versus Strength Endurance Training on Physical Fitness and Sport-Specific Performance in Young Elite Female Rowers}, series = {Frontiers in Physiology}, volume = {11}, journal = {Frontiers in Physiology}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-042X}, doi = {10.3389/fphys.2020.00888}, pages = {12}, year = {2020}, abstract = {Strength training is an important means for performance development in young rowers. The purpose of this study was to examine the effects of a 9-week equal volume heavy-resistance strength training (HRST) versus strength endurance training (SET) in addition to regular rowing training on primary (e.g., maximal strength/power) and secondary outcomes (e.g., balance) in young rowers. Twenty-six female elite adolescent rowers were assigned to an HRST (n = 12; age: 13.2 ± 0.5 yrs; maturity-offset: +2.0 ± 0.5 yrs) or a SET group (n = 14; age: 13.1 ± 0.5 yrs; maturity-offset: +2.1 ± 0.5 yrs). HRST and SET comprised lower- (i.e., leg press/knee flexion/extension), upper-limbs (i.e., bench press/pull; lat-pull down), and complex exercises (i.e., rowing ergometer). HRST performed four sets with 12 repetitions per set at an intensity of 75-95\% of the one-repetition maximum (1-RM). SET conducted four sets with 30 repetitions per set at 50-60\% of the 1-RM. Training volume was matched for overall repetitions × intensity × training per week. Pre-post training, tests were performed for the assessment of primary [i.e., maximal strength (e.g., bench pull/knee flexion/extension 1-RM/isometric handgrip test), muscle power (e.g., medicine-ball push test, triple hop, drop jump, and countermovement jump), anaerobic endurance (400-m run), sport-specific performance (700-m rowing ergometer trial)] and secondary outcomes [dynamic balance (Y-balance test), change-of-direction (CoD) speed (multistage shuttle-run test)]. Adherence rate was >87\% and one athlete of each group dropped out. Overall, 24 athletes completed the study and no test or training-related injuries occurred. Significant group × time interactions were observed for maximal strength, muscle power, anaerobic endurance, CoD speed, and sport-specific performance (p ≤ 0.05; 0.45 ≤ d ≤ 1.11). Post hoc analyses indicated larger gains in maximal strength and muscle power following HRST (p ≤ 0.05; 1.81 ≤ d ≤ 3.58) compared with SET (p ≤ 0.05; 1.04 ≤ d ≤ 2.30). Furthermore, SET (p ≤ 0.01; d = 2.08) resulted in larger gains in sport-specific performance compared with HRST (p < 0.05; d = 1.3). Only HRST produced significant pre-post improvements for anaerobic endurance and CoD speed (p ≤ 0.05; 1.84 ≤ d ≤ 4.76). In conclusion, HRST in addition to regular rowing training was more effective than SET to improve selected measures of physical fitness (i.e., maximal strength, muscle power, anaerobic endurance, and CoD speed) and SET was more effective than HRST to enhance sport-specific performance gains in female elite young rowers.}, language = {en} } @article{ChaabeneLesinskiBehmetal.2020, author = {Chaabene, Helmi and Lesinski, Melanie and Behm, David George and Granacher, Urs}, title = {Performance- and healthrelated benefits of youth resistance training}, series = {Sports Orthopaedics and Traumatology}, volume = {36}, journal = {Sports Orthopaedics and Traumatology}, number = {3}, publisher = {Elsevier}, address = {Amsterdam}, pages = {10}, year = {2020}, abstract = {Performance- and healthrelated benefits of yoThere is ample evidence that youth resistance training (RT) is safe, joyful, and effective for different markers of performance (e.g., muscle strength, power, linear sprint speed) and health (e.g., injury prevention). Accordingly, the first aim of this narrative review is to present and discuss the relevance of muscle strength for youth physical development. The second purpose is to report evidence on the effectiveness of RT on muscular fitness (muscle strength, power, muscle endurance), on movement skill performance and injury prevention in youth. There is evidence that RT is effective in enhancing measures of muscle fitness in children and adolescents, irrespective of sex. Additionally, numerous studies indicate that RT has positive effects on fundamental movement skills (e.g., jumping, running, throwing) in youth regardless of age, maturity, training status, and sex. Further, irrespective of age, sex, and training status, regular exposure to RT (e.g., plyometric training) decreases the risk of sustaining injuries in youth. This implies that RT should be a meaningful element of youths' exercise programming. This has been acknowledged by global (e.g., World Health Organization) and national (e.g., National Strength and Conditioning Association) health- and performance-related organizations which is why they recommended to perform RT as an integral part of weekly exercise programs to promote muscular strength, fundamental movement skills, and to resist injuries in youth.uth resistance training}, language = {en} } @misc{LesinskiSchmelcherHerzetal.2020, author = {Lesinski, Melanie and Schmelcher, Alina and Herz, Michael and Puta, Christian and Gabriel, Holger and Arampatzis, Adamantios and Laube, Gunnar and B{\"u}sch, Dirk and Granacher, Urs}, title = {Maturation-, age-, and sex-specific anthropometric and physical fitness percentiles of German elite young athletes}, series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {662}, issn = {1866-8364}, doi = {10.25932/publishup-48026}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-480268}, pages = {21}, year = {2020}, abstract = {The aim of this study was to establish maturation-, age-, and sex-specific anthropometric and physical fitness percentile reference values of young elite athletes from various sports. Anthropometric (i.e., standing and sitting body height, body mass, body mass index) and physical fitness (i.e., countermovement jump, drop jump, change-of-direction speed [i.e., T-test], trunk muscle endurance [i.e., ventral Bourban test], dynamic lower limbs balance [i.e., Y-balance test], hand grip strength) of 703 male and female elite young athletes aged 8-18 years were collected to aggregate reference values according to maturation, age, and sex. Findings indicate that body height and mass were significantly higher (p<0.001; 0.95≤d≤1.74) in more compared to less mature young athletes as well as with increasing chronological age (p<0.05; 0.66≤d≤3.13). Furthermore, male young athletes were significantly taller and heavier compared to their female counterparts (p<0.001; 0.34≤d≤0.50). In terms of physical fitness, post-pubertal athletes showed better countermovement jump, drop jump, change-of-direction, and handgrip strength performances (p<0.001; 1.57≤d≤8.72) compared to pubertal athletes. Further, countermovement jump, drop jump, change-of-direction, and handgrip strength performances increased with increasing chronological age (p<0.05; 0.29≤d≤4.13). In addition, male athletes outperformed their female counterpart in the countermovement jump, drop jump, change-of-direction, and handgrip strength (p<0.05; 0.17≤d≤0.76). Significant age by sex interactions indicate that sex-specific differences were even more pronounced with increasing age. Conclusively, body height, body mass, and physical fitness increased with increasing maturational status and chronological age. Sex-specific differences appear to be larger as youth grow older. Practitioners can use the percentile values as approximate benchmarks for talent identification and development.}, language = {en} } @misc{ThielePrieskeLesinskietal.2020, author = {Thiele, Dirk and Prieske, Olaf and Lesinski, Melanie and Granacher, Urs}, title = {Effects of Equal Volume Heavy-Resistance Strength Training Versus Strength Endurance Training on Physical Fitness and Sport-Specific Performance in Young Elite Female Rowers}, series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {664}, issn = {1866-8364}, doi = {10.25932/publishup-48196}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-481961}, pages = {14}, year = {2020}, abstract = {Strength training is an important means for performance development in young rowers. The purpose of this study was to examine the effects of a 9-week equal volume heavy-resistance strength training (HRST) versus strength endurance training (SET) in addition to regular rowing training on primary (e.g., maximal strength/power) and secondary outcomes (e.g., balance) in young rowers. Twenty-six female elite adolescent rowers were assigned to an HRST (n = 12; age: 13.2 ± 0.5 yrs; maturity-offset: +2.0 ± 0.5 yrs) or a SET group (n = 14; age: 13.1 ± 0.5 yrs; maturity-offset: +2.1 ± 0.5 yrs). HRST and SET comprised lower- (i.e., leg press/knee flexion/extension), upper-limbs (i.e., bench press/pull; lat-pull down), and complex exercises (i.e., rowing ergometer). HRST performed four sets with 12 repetitions per set at an intensity of 75-95\% of the one-repetition maximum (1-RM). SET conducted four sets with 30 repetitions per set at 50-60\% of the 1-RM. Training volume was matched for overall repetitions × intensity × training per week. Pre-post training, tests were performed for the assessment of primary [i.e., maximal strength (e.g., bench pull/knee flexion/extension 1-RM/isometric handgrip test), muscle power (e.g., medicine-ball push test, triple hop, drop jump, and countermovement jump), anaerobic endurance (400-m run), sport-specific performance (700-m rowing ergometer trial)] and secondary outcomes [dynamic balance (Y-balance test), change-of-direction (CoD) speed (multistage shuttle-run test)]. Adherence rate was >87\% and one athlete of each group dropped out. Overall, 24 athletes completed the study and no test or training-related injuries occurred. Significant group × time interactions were observed for maximal strength, muscle power, anaerobic endurance, CoD speed, and sport-specific performance (p ≤ 0.05; 0.45 ≤ d ≤ 1.11). Post hoc analyses indicated larger gains in maximal strength and muscle power following HRST (p ≤ 0.05; 1.81 ≤ d ≤ 3.58) compared with SET (p ≤ 0.05; 1.04 ≤ d ≤ 2.30). Furthermore, SET (p ≤ 0.01; d = 2.08) resulted in larger gains in sport-specific performance compared with HRST (p < 0.05; d = 1.3). Only HRST produced significant pre-post improvements for anaerobic endurance and CoD speed (p ≤ 0.05; 1.84 ≤ d ≤ 4.76). In conclusion, HRST in addition to regular rowing training was more effective than SET to improve selected measures of physical fitness (i.e., maximal strength, muscle power, anaerobic endurance, and CoD speed) and SET was more effective than HRST to enhance sport-specific performance gains in female elite young rowers.}, language = {en} } @article{LesinskiSchmelcherHerzetal.2020, author = {Lesinski, Melanie and Schmelcher, Alina and Herz, Michael and Puta, Christian and Gabriel, Holger and Arampatzis, Adamantios and Laube, Gunnar and B{\"u}sch, Dirk and Granacher, Urs}, title = {Maturation-, age-, and sex-specific anthropometric and physical fitness percentiles of German elite young athletes}, series = {Plos One}, volume = {15}, journal = {Plos One}, number = {8}, publisher = {Plos One}, address = {San Francisco, California}, issn = {1932-6203}, doi = {10.1371/journal.pone.0237423}, pages = {19}, year = {2020}, abstract = {The aim of this study was to establish maturation-, age-, and sex-specific anthropometric and physical fitness percentile reference values of young elite athletes from various sports. Anthropometric (i.e., standing and sitting body height, body mass, body mass index) and physical fitness (i.e., countermovement jump, drop jump, change-of-direction speed [i.e., T-test], trunk muscle endurance [i.e., ventral Bourban test], dynamic lower limbs balance [i.e., Y-balance test], hand grip strength) of 703 male and female elite young athletes aged 8-18 years were collected to aggregate reference values according to maturation, age, and sex. Findings indicate that body height and mass were significantly higher (p<0.001; 0.95≤d≤1.74) in more compared to less mature young athletes as well as with increasing chronological age (p<0.05; 0.66≤d≤3.13). Furthermore, male young athletes were significantly taller and heavier compared to their female counterparts (p<0.001; 0.34≤d≤0.50). In terms of physical fitness, post-pubertal athletes showed better countermovement jump, drop jump, change-of-direction, and handgrip strength performances (p<0.001; 1.57≤d≤8.72) compared to pubertal athletes. Further, countermovement jump, drop jump, change-of-direction, and handgrip strength performances increased with increasing chronological age (p<0.05; 0.29≤d≤4.13). In addition, male athletes outperformed their female counterpart in the countermovement jump, drop jump, change-of-direction, and handgrip strength (p<0.05; 0.17≤d≤0.76). Significant age by sex interactions indicate that sex-specific differences were even more pronounced with increasing age. Conclusively, body height, body mass, and physical fitness increased with increasing maturational status and chronological age. Sex-specific differences appear to be larger as youth grow older. Practitioners can use the percentile values as approximate benchmarks for talent identification and development.}, language = {en} } @misc{ChaabenePrieskeLesinskietal.2019, author = {Chaabene, Helmi and Prieske, Olaf and Lesinski, Melanie and Sandau, Ingo and Granacher, Urs}, title = {Short-term seasonal development of anthropometry, body composition, physical fitness, and sport-specific performance in young olympic weightlifters}, series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {685}, issn = {1866-8364}, doi = {10.25932/publishup-47260}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-472609}, pages = {15}, year = {2019}, abstract = {The aim of this study is to monitor short-term seasonal development of young Olympic weightlifters' anthropometry, body composition, physical fitness, and sport-specific performance. Fifteen male weightlifters aged 13.2 ± 1.3 years participated in this study. Tests for the assessment of anthropometry (e.g., body-height, body-mass), body-composition (e.g., lean-body-mass, relative fat-mass), muscle strength (grip-strength), jump performance (drop-jump (DJ) height, countermovement-jump (CMJ) height, DJ contact time, DJ reactive-strength-index (RSI)), dynamic balance (Y-balance-test), and sport-specific performance (i.e., snatch and clean-and-jerk) were conducted at different time-points (i.e., T1 (baseline), T2 (9 weeks), T3 (20 weeks)). Strength tests (i.e., grip strength, clean-and-jerk and snatch) and training volume were normalized to body mass. Results showed small-to-large increases in body-height, body-mass, lean-body-mass, and lower-limbs lean-mass from T1-to-T2 and T2-to-T3 (∆0.7-6.7\%; 0.1 ≤ d ≤ 1.2). For fat-mass, a significant small-sized decrease was found from T1-to-T2 (∆13.1\%; d = 0.4) and a significant increase from T2-to-T3 (∆9.1\%; d = 0.3). A significant main effect of time was observed for DJ contact time (d = 1.3) with a trend toward a significant decrease from T1-to-T2 (∆-15.3\%; d = 0.66; p = 0.06). For RSI, significant small increases from T1-to-T2 (∆9.9\%, d = 0.5) were noted. Additionally, a significant main effect of time was found for snatch (d = 2.7) and clean-and-jerk (d = 3.1) with significant small-to-moderate increases for both tests from T1-to-T2 and T2-to-T3 (∆4.6-11.3\%, d = 0.33 to 0.64). The other tests did not change significantly over time (0.1 ≤ d ≤ 0.8). Results showed significantly higher training volume for sport-specific training during the second period compared with the first period (d = 2.2). Five months of Olympic weightlifting contributed to significant changes in anthropometry, body-composition, and sport-specific performance. However, hardly any significant gains were observed for measures of physical fitness. Coaches are advised to design training programs that target a variety of fitness components to lay an appropriate foundation for later performance as an elite athlete.}, language = {en} } @article{ChaabenePrieskeLesinskietal.2019, author = {Chaabene, Helmi and Prieske, Olaf and Lesinski, Melanie and Sandau, Ingo and Granacher, Urs}, title = {Short-Term Seasonal Development of Anthropometry, Body Composition, Physical Fitness, and Sport-Specific Performance in Young Olympic Weightlifters}, series = {Sports}, volume = {7}, journal = {Sports}, number = {12}, publisher = {MDPI}, address = {Basel}, issn = {2075-4663}, doi = {10.3390/sports7120242}, pages = {13}, year = {2019}, language = {en} } @misc{GebelLesinskiBehmetal.2018, author = {Gebel, Arnd and Lesinski, Melanie and Behm, David George and Granacher, Urs}, title = {Effects and dose-response relationship of balance training on balance performance in Youth}, series = {Sports medicine}, volume = {48}, journal = {Sports medicine}, number = {9}, publisher = {Springer}, address = {Northcote}, issn = {0112-1642}, doi = {10.1007/s40279-018-0926-0}, pages = {2067 -- 2089}, year = {2018}, abstract = {Background Effects and dose-response relationships of balance training on measures of balance are well-documented for healthy young and old adults. However, this has not been systematically studied in youth. Objectives The objectives of this systematic review and meta-analysis were to quantify effects of balance training (BT) on measures of static and dynamic balance in healthy children and adolescents. Additionally, dose-response relations for BT modalities (e.g. training period, frequency, volume) were quantified through the analysis of controlled trials. Data Sources A computerized systematic literature search was conducted in the electronic databases PubMed and Web of Science from January 1986 until June 2017 to identify articles related to BT in healthy trained and untrained children and adolescents. Study Eligibility Criteria A systematic approach was used to evaluate articles that examined the effects of BT on balance outcomes in youth. Controlled trials with pre- and post-measures were included if they examined healthy youth with a mean age of 6-19 years and assessed at least one measure of balance (i.e. static/dynamic steady-state balance, reactive balance, proactive balance) with behavioural (e.g. time during single-leg stance) or biomechanical (e.g. centre of pressure displacements during single-leg stance) test methods. Study Appraisal and Synthesis Methods The included studies were coded for the following criteria: training modalities (i.e. training period, frequency, volume), balance outcomes (i.e. static and dynamic balance) as well as chronological age, sex (male vs. female), training status (trained vs. untrained), setting (school vs. club), and testing method (biomechanical vs. physical fitness test). Weighted mean standardized mean differences (SMDwm) were calculated using a random-effects model to compute overall intervention effects relative to active and passive control groups. Between-study heterogeneity was assessed using I 2 and chi(2) statistics. A multivariate random effects meta-regression was computed to explain the influence of key training modalities (i.e. training period, training frequency, total number of training sessions, duration of training sessions, and total duration of training per week) on the effectiveness of BT on measures of balance performance. Further, subgroup univariate analyses were computed for each training modality. Additionally, dose-response relationships were characterized independently by interpreting the modality specific magnitude of effect sizes. Methodological quality of the included studies was rated with the help of the Physiotherapy Evidence Database (PEDro) Scale. Results Overall, our literature search revealed 198 hits of which 17 studies were eligible for inclusion in this systematic review and meta-analysis. Irrespective of age, sex, training status, sport discipline and training method, moderate to large BT-related effects were found for measures of static (SMDwm = 0.71) and dynamic (SMDwm = 1.03) balance in youth. However, our subgroup analyses did not reveal any statistically significant effects of the moderator variables age, sex, training status, setting and testing method on overall balance (i.e. aggregation of static and dynamic balance). BT-related effects in adolescents were moderate to large for measures of static (SMDwm = 0.61) and dynamic (SMDwm = 0.86) balance. With regard to the dose-response relationships, findings from the multivariate random effects meta-regression revealed that none of the examined training modalities predicted the effects of BT on balance performance in adolescents (R-2 = 0.00). In addition, results from univariate analysis have to be interpreted with caution because training modalities were computed as single factors irrespective of potential between-modality interactions. For training period, 12 weeks of training achieved the largest effect (SMDwm = 1.40). For training frequency, the largest effect was found for two sessions per week (SMDwm = 1.29). For total number of training sessions, the largest effect was observed for 24-36 sessions (SMDwm = 1.58). For the modality duration of a single training session, 4-15 min reached the largest effect (SMDwm = 1.03). Finally, for the modality training per week, a total duration of 31-60 min per week (SMDwm = 1.33) provided the largest effects on overall balance in adolescents. Methodological quality of the studies was rated as moderate with a median PEDro score of 6.0. Limitations Dose-response relationships were calculated independently for training modalities (i.e. modality specific) and not interdependently. Training intensity was not considered for the calculation of dose-response relationships because the included studies did not report this training modality. Further, the number of included studies allowed the characterization of dose-response relationships in adolescents for overall balance only. In addition, our analyses revealed a considerable between-study heterogeneity (I-2 = 66-83\%). The results of this meta-analysis have to be interpreted with caution due to their preliminary status. Conclusions BT is a highly effective means to improve balance performance with moderate to large effects on static and dynamic balance in healthy youth irrespective of age, sex, training status, setting and testing method. The examined training modalities did not have a moderating effect on balance performance in healthy adolescents. Thus, we conclude that an additional but so far unidentified training modality may have a major effect on balance performance that was not assessed in our analysis. Training intensity could be a promising candidate. However, future studies are needed to find appropriate methods to assess BT intensity.}, language = {en} } @article{WeberPutaLesinskietal.2018, author = {Weber, Stephanie and Puta, Christian and Lesinski, Melanie and Gabriel, Brunhild and Steidten, Thomas and B{\"a}r, Karl-J{\"u}rgen and Herbsleb, Marco and Granacher, Urs and Gabriel, Holger H. W.}, title = {Symptoms of anxiety and depression in young athletes using the hospital anxiety and depression scale}, series = {Frontiers in physiology}, volume = {9}, journal = {Frontiers in physiology}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-042X}, doi = {10.3389/fphys.2018.00182}, pages = {12}, year = {2018}, abstract = {Elite young athletes have to cope with multiple psychological demands such as training volume, mental and physical fatigue, spatial separation of family and friends or time management problems may lead to reduced mental and physical recovery. While normative data regarding symptoms of anxiety and depression for the general population is available (Hinz and Brahler, 2011), hardly any information exists for adolescents in general and young athletes in particular. Therefore, the aim of this study was to assess overall symptoms of anxiety and depression in young athletes as well as possible sex differences. The survey was carried out within the scope of the study "Resistance Training in Young Athletes" (KINGS-Study). Between August 2015 and September 2016, 326 young athletes aged (mean +/- SD) 14.3 +/- 1.6 years completed the Hospital Anxiety and Depression Scale (HAD Scale). Regarding the analysis of age on the anxiety and depression subscales, age groups were classified as follows: late childhood (12-14 years) and late adolescence (15-18 years). The participating young athletes were recruited from Olympic weight lifting, handball, judo, track and field athletics, boxing, soccer, gymnastics, ice speed skating, volleyball, and rowing. Anxiety and depression scores were (mean +/- SD) 4.3 +/- 3.0 and 2.8 +/- 2.9, respectively. In the subscale anxiety, 22 cases (6.7\%) showed subclinical scores and 11 cases (3.4\%) showed clinical relevant score values. When analyzing the depression subscale, 31 cases (9.5\%) showed subclinical score values and 12 cases (3.7\%) showed clinically important values. No significant differences were found between male and female athletes (p >= 0.05). No statistically significant differences in the HADS scores were found between male athletes of late childhood and late adolescents (p >= 0.05). To the best of our knowledge, this is the first report describing questionnaire based indicators of symptoms of anxiety and depression in young athletes. Our data implies the need for sports medical as well as sports psychiatric support for young athletes. In addition, our results demonstrated that the chronological classification concerning age did not influence HAD Scale outcomes. Future research should focus on sports medical and sports psychiatric interventional approaches with the goal to prevent anxiety and depression as well as teaching coping strategies to young athletes.}, language = {en} } @misc{WeberPutaLesinskietal.2018, author = {Weber, Stephanie and Puta, Christian and Lesinski, Melanie and Gabriel, Brunhild and Steidten, Thomas and B{\"a}r, Karl-J{\"u}rgen and Herbsleb, Marco and Granacher, Urs and Gabriel, Holger H. W.}, title = {Symptoms of anxiety and depression in young athletes using the Hospital Anxiety and Depression Scale}, series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {638}, issn = {1866-8364}, doi = {10.25932/publishup-44560}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-445602}, pages = {14}, year = {2018}, abstract = {Elite young athletes have to cope with multiple psychological demands such as training volume, mental and physical fatigue, spatial separation of family and friends or time management problems may lead to reduced mental and physical recovery. While normative data regarding symptoms of anxiety and depression for the general population is available (Hinz and Brahler, 2011), hardly any information exists for adolescents in general and young athletes in particular. Therefore, the aim of this study was to assess overall symptoms of anxiety and depression in young athletes as well as possible sex differences. The survey was carried out within the scope of the study "Resistance Training in Young Athletes" (KINGS-Study). Between August 2015 and September 2016, 326 young athletes aged (mean +/- SD) 14.3 +/- 1.6 years completed the Hospital Anxiety and Depression Scale (HAD Scale). Regarding the analysis of age on the anxiety and depression subscales, age groups were classified as follows: late childhood (12-14 years) and late adolescence (15-18 years). The participating young athletes were recruited from Olympic weight lifting, handball, judo, track and field athletics, boxing, soccer, gymnastics, ice speed skating, volleyball, and rowing. Anxiety and depression scores were (mean +/- SD) 4.3 +/- 3.0 and 2.8 +/- 2.9, respectively. In the subscale anxiety, 22 cases (6.7\%) showed subclinical scores and 11 cases (3.4\%) showed clinical relevant score values. When analyzing the depression subscale, 31 cases (9.5\%) showed subclinical score values and 12 cases (3.7\%) showed clinically important values. No significant differences were found between male and female athletes (p >= 0.05). No statistically significant differences in the HADS scores were found between male athletes of late childhood and late adolescents (p >= 0.05). To the best of our knowledge, this is the first report describing questionnaire based indicators of symptoms of anxiety and depression in young athletes. Our data implies the need for sports medical as well as sports psychiatric support for young athletes. In addition, our results demonstrated that the chronological classification concerning age did not influence HAD Scale outcomes. Future research should focus on sports medical and sports psychiatric interventional approaches with the goal to prevent anxiety and depression as well as teaching coping strategies to young athletes.}, language = {en} } @article{LesinskiPrieskeBordeetal.2018, author = {Lesinski, Melanie and Prieske, Olaf and Borde, Ron and Beurskens, Rainer and Granacher, Urs}, title = {Effects of Different Footwear Properties and Surface Instability on Neuromuscular Activity and Kinematics During Jumping}, series = {Journal of strength and conditioning research : the research journal of the NSCA}, volume = {32}, journal = {Journal of strength and conditioning research : the research journal of the NSCA}, number = {11}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia}, issn = {1064-8011}, doi = {10.1519/JSC.0000000000002556}, pages = {3246 -- 3257}, year = {2018}, abstract = {The purpose of this study was to examine sex-specific effects of different footwear properties vs. barefoot condition during the performance of drop jumps (DJs) on stable and unstable surfaces on measures of jump performance, electromyographic (EMG) activity, and knee joint kinematics. Drop jump performance, EMG activity of lower-extremity muscles, as well as sagittal and frontal knee joint kinematics were tested in 28 healthy male (n = 14) and female (n = 14) physically active sports science students (23 6 2 years) during the performance of DJs on stable and unstable surfaces using different footwear properties (elastic vs. minimal shoes) vs. barefoot condition. Analysis revealed a significantly lower jump height and performance index (Delta 7-12\%; p < 0.001; 2.22 <= d = 2.90) during DJs on unstable compared with stable surfaces. This was accompanied by lower thigh/shank muscle activities (Delta 11-28\%; p < 0.05; 0.99 <= d = 2.16) and knee flexion angles (Delta 5-8\%; p < 0.05; 1.02 <= d = 2.09). Furthermore, knee valgus angles during DJs were significantly lower when wearing shoes compared with barefoot condition (Delta 22-32\%; p < 0.01; 1.38 <= d = 3.31). Sex-specific analyses indicated higher knee flexion angles in females compared with males during DJs, irrespective of the examined surface and footwear conditions (Delta 29\%; p < 0.05; d = 0.92). Finally, hardly any significant footwear-surface interactions were detected. Our findings revealed that surface instability had an impact on DJ performance, thigh/shank muscle activity, and knee joint kinematics. In addition, the single factors "footwear" and "sex" modulated knee joint kinematics during DJs. However, hardly any significant interaction effects were found. Thus, additional footwear-related effects can be neglected when performing DJs during training on different surfaces.}, 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{PrieskeDempsLesinskietal.2017, author = {Prieske, Olaf and Demps, Marie and Lesinski, Melanie and Granacher, Urs}, title = {Combined Effects of Fatigue and Surface Instability on Jump Biomechanics in Elite Athletes}, series = {International journal of sports medicine}, volume = {38}, journal = {International journal of sports medicine}, publisher = {Thieme}, address = {Stuttgart}, issn = {0172-4622}, doi = {10.1055/s-0043-111894}, pages = {781 -- 790}, year = {2017}, abstract = {The present study aimed to examine the effects of fatigue and surface instability on kinetic and kinematic jump performance measures. Ten female and 10 male elite volleyball players (18 +/- 2 years) performed repetitive vertical double-leg box jumps until failure. Pre and post fatigue, jump height/performance index, ground reaction force and knee flexion/valgus angles were assessed during drop and countermovement jumps on stable and unstable surfaces. Fatigue, surface condition, and sex resulted in significantly lower drop jump performance and ground reaction force (p0.031, 1.1d3.5). Additionally, drop jump knee flexion angles were significantly lower following fatigue (p=0.006, d=1.5). A significant fatiguexsurfacexsex interaction (p=0.020, d=1.2) revealed fatigue-related decrements in drop jump peak knee flexion angles under unstable conditions and in men only. Knee valgus angles were higher on unstable compared to stable surfaces during drop jumps and in females compared to males during drop and countermovement jumps (p0.054, 1.0d1.1). Significant surfacexsex interactions during countermovement jumps (p=0.002, d=1.9) indicated that knee valgus angles at onset of ground contact were significantly lower on unstable compared to stable surfaces in males but higher in females. Our findings revealed that fatigue and surface instability resulted in sex-specific knee motion strategies during jumping in elite volleyball players.}, language = {en} } @article{LesinskiPrieskeBeurskensetal.2017, author = {Lesinski, Melanie and Prieske, Olaf and Beurskens, Rainer and Behm, David George and Granacher, Urs}, title = {Effects of drop height and surface instability on neuromuscular activation during drop jumps}, series = {Scandinavian journal of medicine \& science in sports}, volume = {27}, journal = {Scandinavian journal of medicine \& science in sports}, publisher = {Wiley}, address = {Hoboken}, issn = {0905-7188}, doi = {10.1111/sms.12732}, pages = {1090 -- 1098}, year = {2017}, abstract = {The purpose of this study was to examine whether drop height-induced changes in leg muscle activity during drop jumps (DJ) are additionally modulated by surface condition. Twenty-four healthy participants (23.7 +/- 1.8years) performed DJs on a force plate on stable, unstable, and highly unstable surfaces using different drop heights (i.e., 20cm, 40cm, 60cm). Electromyographic (EMG) activity of soleus (SOL), gastrocnemius (GM), tibialis anterior (TA) muscles and coactivation of TA/SOL and TA/GM were analyzed for time intervals 100ms prior to ground contact (preactivation) and 30-60ms after ground contact [short latency response (SLR)]. Increasing drop heights resulted in progressively increased SOL and GM activity during preactivation and SLR (P<0.01; 1.01 d 5.34) while TA/SOL coactivation decreased (P<0.05; 0.51 d 3.01). Increasing surface instability produced decreased activities during preactivation (GM) and SLR (GM, SOL) (P<0.05; 1.36 d 4.30). Coactivation increased during SLR (P<0.05; 1.50 d 2.58). A significant drop heightxsurface interaction was observed for SOL during SLR. Lower SOL activity was found on unstable compared to stable surfaces for drop heights 40cm (P<0.05; 1.25 d 2.12). Findings revealed that instability-related changes in activity of selected leg muscles are minimally affected by drop height.}, language = {en} } @misc{LesinskiMuehlbauerGranacher2017, author = {Lesinski, Melanie and M{\"u}hlbauer, Thomas and Granacher, Urs}, title = {Concurrent validity of the Gyko inertial sensor system for the assessment of vertical jump height in female sub-elite youth soccer players}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-400967}, pages = {9}, year = {2017}, abstract = {Background: The aim of the present study was to verify concurrent validity of the Gyko inertial sensor system for the assessment of vertical jump height. - Methods: Nineteen female sub-elite youth soccer players (mean age: 14.7 ± 0.6 years) performed three trials of countermovement (CMJ) and squat jumps (SJ), respectively. Maximal vertical jump height was simultaneously quantified with the Gyko system, a Kistler force-plate (i.e., gold standard), and another criterion device that is frequently used in the field, the Optojump system. - Results: Compared to the force-plate, the Gyko system determined significant systematic bias for mean CMJ (-0.66 cm, p < 0.01, d = 1.41) and mean SJ (-0.91 cm, p < 0.01, d = 1.69) height. Random bias was ± 3.2 cm for CMJ and ± 4.0 cm for SJ height and intraclass correlation coefficients (ICCs) were "excellent" (ICC = 0.87 for CMJ and 0.81 for SJ). Compared to the Optojump device, the Gyko system detected a significant systematic bias for mean CMJ (0.55 cm, p < 0.05, d = 0.94) but not for mean SJ (0.39 cm) height. Random bias was ± 3.3 cm for CMJ and ± 4.2 cm for SJ height and ICC values were "excellent" (ICC = 0.86 for CMJ and 0.82 for SJ). - Conclusion: Consequently, apparatus specific regression equations were provided to estimate true vertical jump height for the Kistler force-plate and the Optojump device from Gyko-derived data. Our findings indicate that the Gyko system cannot be used interchangeably with a Kistler force-plate and the Optojump device in trained individuals. It is suggested that practitioners apply the correction equations to estimate vertical jump height for the force-plate and the Optojump system from Gyko-derived data.}, language = {en} } @article{LesinskiPrieskeBeurskensetal.2017, author = {Lesinski, Melanie and Prieske, Olaf and Beurskens, Rainer and Behm, David George and Granacher, Urs}, title = {Effects of Drop-height and Surface Instability on Jump Performance and Knee Kinematics}, series = {International journal of sports medicine}, volume = {39}, journal = {International journal of sports medicine}, number = {1}, publisher = {Thieme}, address = {Stuttgart}, issn = {0172-4622}, doi = {10.1055/s-0043-117610}, pages = {50 -- 57}, year = {2017}, abstract = {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.}, language = {en} } @misc{GranacherLesinskiBueschetal.2016, author = {Granacher, Urs and Lesinski, Melanie and Buesch, Dirk and M{\"u}hlbauer, Thomas and Prieske, Olaf and Puta, Christian and Gollhofer, Albert and Behm, David George}, title = {Effects of Resistance Training in Youth Athletes on Muscular Fitness and Athletic Performance: A Conceptual Model for Long-Term Athlete Development}, series = {Frontiers in physiology}, volume = {7}, journal = {Frontiers in physiology}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-042X}, doi = {10.3389/fphys.2016.00164}, pages = {14}, year = {2016}, abstract = {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.}, language = {en} }