@article{PrieskeChaabeneKullmannetal.2022,
  author    = {Prieske, Olaf and Chaabene, Helmi and Kullmann, Niclas and Granacher, Urs},
  title     = {Effects of Individualized Versus Traditional Power Training on Strength, Power, Jump Performances, and Body Composition in Young Male Nordic Athletes},
  series = {International journal of sports physiology and performance},
  volume    = {17},
  journal   = {International journal of sports physiology and performance},
  number    = {4},
  publisher = {Human Kinetics Publ.},
  address   = {Champaign},
  issn      = {1555-0265},
  doi       = {10.1123/ijspp.2021-0074},
  pages     = {541 -- 548},
  year      = {2022},
  abstract  = {Purpose: This study aimed to examine the effects of individualized-load power training (IPT) versus traditional moderate-load power training (TPT) on strength, power, jump performance, and body composition in elite young Nordic athletes. Methods: In a randomized crossover design, 10 young male athletes (ski jumpers, Nordic combined athletes) age 17.5 (0.6) years (biological maturity status: +3.5 y postpeak height velocity) who competed on a national or international level performed 5 weeks of IPT (4 x 5 repetitions at 49\%-72\% 1-repetiton maximum [RM]) and TPT (5 x 5 repetitions at 50\%-60\% 1-RM) in addition to their regular training. Testing before, between, and after both training blocks comprised the assessment of muscle strength (loaded back squat 3-RM), power (maximal loaded back squat power), jump performance (eg, drop-jump height, reactive strength index), and body composition (eg, skeletal muscle mass). Results: Significant, large-size main effects for time were found for muscle strength (P < .01; g = 2.7), reactive strength index (P = .03; g= 1.6), and drop jump height (P = .02; g= 1.9) irrespective of the training condition (IPT, TPT). No significant time-by-condition interactions were observed. For measures of body composition, no significant main effects of condition and time or time-by-condition interactions were found. Conclusions: Our findings demonstrate that short-term IPT and TPT at moderate loads in addition to regular training were equally effective in improving measures of muscle strength (loaded back squat 3-RM) and vertical jump performance (reactive strength index, drop jump, and height) in young Nordic athletes.},
  language  = {en}
}
@article{SammoudNegraBouguezzietal.2021,
  author    = {Sammoud, Senda and Negra, Yassine and Bouguezzi, Raja and Hachana, Younes and Granacher, Urs and Chaabene, Helmi},
  title     = {The effects of plyometric jump training on jump and sport-specific performances in prepubertal female swimmers},
  series = {Journal of exercise science and fitness : JESF : official journal of The Society of Chinese Scholars on Exercise Physiology and Fitness and Hong Kong Association of Sports Medicine \& Sports Science},
  volume    = {19},
  journal   = {Journal of exercise science and fitness : JESF : official journal of The Society of Chinese Scholars on Exercise Physiology and Fitness and Hong Kong Association of Sports Medicine \& Sports Science},
  number    = {1},
  publisher = {Elsevier},
  address   = {Singapore},
  issn      = {1728-869x},
  doi       = {10.1016/j.jesf.2020.07.003},
  pages     = {25 -- 31},
  year      = {2021},
  abstract  = {Background/objective Dry land-training (e.g., plyometric jump training) can be a useful mean to improve swimming performance. This study examined the effects of an 8-week plyometric jump training (PJT) program on jump and sport-specific performances in prepubertal female swimmers. Methods Twenty-two girls were randomly assigned to either a plyometric jump training group (PJTG; n = 12, age: 10.01 ± 0.57 years, maturity-offset = -1.50 ± 0.50, body mass = 36.39 ± 6.32 kg, body height = 146.90 ± 7.62 cm, body mass index = 16.50 ± 1.73 kg/m2) or an active control (CG; n = 10, age: 10.50 ± 0.28 years, maturity-offset = -1.34 ± 0.51, body mass = 38.41 ± 9.42 kg, body height = 143.60 ± 5.05 cm, body mass index = 18.48 ± 3.77 kg/m2). Pre- and post-training, tests were conducted for the assessment of muscle power (e.g., countermovement-jump [CMJ], standing-long-jump [SLJ]). Sport-specific-performances were tested using the timed 25 and 50-m front crawl with a diving-start, timed 25-m front crawl without push-off from the wall (25-m WP), and a timed 25-m kick without push-off from the wall (25-m KWP). Results Findings showed a significant main effect of time for the CMJ (d = 0.78), the SLJ (d = 0.91), 25-m front crawl test (d = 2.5), and the 25-m-KWP (d = 1.38) test. Significant group × time interactions were found for CMJ, SLJ, 25-m front crawl, 50-m front crawl, 25-m KWP, and 25-m WP test (d = 0.29-1.63) in favor of PJTG (d = 1.34-3.50). No significant pre-post changes were found for CG (p > 0.05). Conclusion In sum, PJT is effective in improving muscle power and sport-specific performances in prepubertal swimmers. Therefore, PJT should be included from an early start into the regular training program of swimmers.},
  language  = {en}
}
@article{HammamiChaabeneKharratetal.2021,
  author    = {Hammami, Raouf and Chaabene, Helmi and Kharrat, Fatma and Werfelli, Hanen and Duncan, Michael and Rebai, Haithem and Granacher, Urs},
  title     = {Acute effects of different balance exercise types on selected measures of physical fitness in youth female volleyball players},
  series = {BMC Sports Science, Medicine and Rehabilitation},
  volume    = {13},
  journal   = {BMC Sports Science, Medicine and Rehabilitation},
  publisher = {BioMed Central},
  address   = {London},
  issn      = {1758-2555},
  doi       = {10.1186/s13102-021-00249-5},
  pages     = {8},
  year      = {2021},
  abstract  = {Background Earlier studies have shown that balance training (BT) has the potential to induce performance enhancements in selected components of physical fitness (i.e., balance, muscle strength, power, speed). While there is ample evidence on the long-term effects of BT on components of physical fitness in youth, less is known on the short-term or acute effects of single BT sessions on selected measures of physical fitness. Objective To examine the acute effects of different balance exercise types on balance, change-of-direction (CoD) speed, and jump performance in youth female volleyball players. Methods Eleven female players aged 14 years participated in this study. Three types of balance exercises (i.e., anterior, posterolateral, rotational type) were conducted in randomized order. For each exercise, 3 sets including 5 repetitions were performed. Before and after the performance of the balance exercises, participants were tested for their static balance (center of pressure surface area [CoP SA] and velocity [CoP V]) on foam and firm surfaces, CoD speed (T-Half test), and vertical jump height (countermovement jump [CMJ] height). A 3 (condition: anterior, mediolateral, rotational balance exercise type) × 2 (time: pre, post) analysis of variance was computed with repeated measures on time. Results Findings showed no significant condition × time interactions for all outcome measures (p > 0.05). However, there were small main effects of time for CoP SA on firm and foam surfaces (both d = 0.38; all p < 0.05) with no effect for CoP V on both surface conditions (p > 0.05). For CoD speed, findings showed a large main effect of time (d = 0.91; p < 0.001). However, for CMJ height, no main effect of time was observed (p > 0.05). Conclusions Overall, our results indicated small-to-large changes in balance and CoD speed performances but not in CMJ height in youth female volleyball players, regardless of the balance exercise type. Accordingly, it is recommended to regularly integrate balance exercises before the performance of sport-specific training to optimize performance development in youth female volleyball players.},
  language  = {en}
}
@misc{NevillNegraMyersetal.2021,
  author    = {Nevill, Alan M. and Negra, Yassine and Myers, Tony D. and Duncan, Michael J. and Chaabene, Helmi and Granacher, Urs},
  title     = {Are Early or Late Maturers Likely to Be Fitter in the General Population?},
  series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  number    = {695},
  issn      = {1866-8364},
  doi       = {10.25932/publishup-48992},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-489928},
  pages     = {18},
  year      = {2021},
  abstract  = {The present study aims to identify the optimal body-size/shape and maturity characteristics associated with superior fitness test performances having controlled for body-size, sex, and chronological-age differences. The sample consisted of 597 Tunisian children (396 boys and 201 girls) aged 8 to 15 years. Three sprint speeds recorded at 10, 20 and 30 m; two vertical and two horizontal jump tests; a change-of-direction and a handgrip-strength tests, were assessed during physical-education classes. Allometric modelling was used to identify the benefit of being an early or late maturer. Findings showed that being tall and light is the ideal shape to be successful at most physical fitness tests, but the height-to-weight "shape" ratio seems to be test-dependent. Having controlled for body-size/shape, sex, and chronological age, the model identified maturity-offset as an additional predictor. Boys who go earlier/younger through peak-height-velocity (PHV) outperform those who go at a later/older age. However, most of the girls' physical-fitness tests peaked at the age at PHV and decline thereafter. Girls whose age at PHV was near the middle of the age range would appear to have an advantage compared to early or late maturers. These findings have important implications for talent scouts and coaches wishing to recruit children into their sports/athletic clubs.},
  language  = {en}
}
@misc{SandauChaabeneGranacher2021,
  author    = {Sandau, Ingo and Chaabene, Helmi and Granacher, Urs},
  title     = {Concurrent validity of barbell force measured from video-based barbell kinematics during the snatch in male elite weightlifters},
  series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  number    = {716},
  issn      = {1866-8364},
  doi       = {10.25932/publishup-52167},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-521678},
  pages     = {13},
  year      = {2021},
  abstract  = {This study examined the concurrent validity of an inverse dynamic (force computed from barbell acceleration [reference method]) and a work-energy (force computed from work at the barbell [alternative method]) approach to measure the mean vertical barbell force during the snatch using kinematic data from video analysis. For this purpose, the acceleration phase of the snatch was analyzed in thirty male medal winners of the 2018 weightlifting World Championships (age: 25.2±3.1 years; body mass: 88.9±28.6 kg). Vertical barbell kinematics were measured using a custom-made 2D real-time video analysis software. Agreement between the two computational approaches was assessed using Bland-Altman analysis, Deming regression, and Pearson product-moment correlation. Further, principal component analysis in conjunction with multiple linear regression was used to assess whether individual differences related to the two approaches are due to the waveforms of the acceleration time-series data. Results indicated no mean difference (p > 0.05; d = -0.04) and an extremely large correlation (r = 0.99) between the two approaches. Despite the high agreement, the total error of individual differences was 8.2\% (163.0 N). The individual differences can be explained by a multiple linear regression model (R2adj = 0.86) on principal component scores from the principal component analysis of vertical barbell acceleration time-series waveforms. Findings from this study indicate that the individual errors of force measures can be associated with the inverse dynamic approach. This approach uses vertical barbell acceleration data from video analysis that is prone to error. Therefore, it is recommended to use the work-energy approach to compute mean vertical barbell force as this approach did not rely on vertical barbell acceleration.},
  language  = {en}
}
@article{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}
}
@article{NevillNegraMyersetal.2021,
  author    = {Nevill, Alan M. and Negra, Yassine and Myers, Tony D. and Duncan, Michael J. and Chaabene, Helmi and Granacher, Urs},
  title     = {Are Early or Late Maturers Likely to Be Fitter in the General Population?},
  series = {International Journal of Environmental Research and Public Health},
  volume    = {18},
  journal   = {International Journal of Environmental Research and Public Health},
  number    = {2},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1660-4601},
  doi       = {10.3390/ijerph18020497},
  pages     = {16},
  year      = {2021},
  abstract  = {The present study aims to identify the optimal body-size/shape and maturity characteristics associated with superior fitness test performances having controlled for body-size, sex, and chronological-age differences. The sample consisted of 597 Tunisian children (396 boys and 201 girls) aged 8 to 15 years. Three sprint speeds recorded at 10, 20 and 30 m; two vertical and two horizontal jump tests; a change-of-direction and a handgrip-strength tests, were assessed during physical-education classes. Allometric modelling was used to identify the benefit of being an early or late maturer. Findings showed that being tall and light is the ideal shape to be successful at most physical fitness tests, but the height-to-weight "shape" ratio seems to be test-dependent. Having controlled for body-size/shape, sex, and chronological age, the model identified maturity-offset as an additional predictor. Boys who go earlier/younger through peak-height-velocity (PHV) outperform those who go at a later/older age. However, most of the girls' physical-fitness tests peaked at the age at PHV and decline thereafter. Girls whose age at PHV was near the middle of the age range would appear to have an advantage compared to early or late maturers. These findings have important implications for talent scouts and coaches wishing to recruit children into their sports/athletic clubs.},
  language  = {en}
}
@article{SandauChaabeneGranacher2021,
  author    = {Sandau, Ingo and Chaabene, Helmi and Granacher, Urs},
  title     = {Concurrent validity of barbell force measured from video-based barbell kinematics during the snatch in male elite weightlifters},
  series = {PLOS ONE / Public Library of Science},
  volume    = {16},
  journal   = {PLOS ONE / Public Library of Science},
  number    = {7},
  publisher = {PLOS},
  address   = {San Francisco},
  issn      = {1932-6203},
  doi       = {10.1371/journal.pone.0254705},
  pages     = {11},
  year      = {2021},
  abstract  = {This study examined the concurrent validity of an inverse dynamic (force computed from barbell acceleration [reference method]) and a work-energy (force computed from work at the barbell [alternative method]) approach to measure the mean vertical barbell force during the snatch using kinematic data from video analysis. For this purpose, the acceleration phase of the snatch was analyzed in thirty male medal winners of the 2018 weightlifting World Championships (age: 25.2±3.1 years; body mass: 88.9±28.6 kg). Vertical barbell kinematics were measured using a custom-made 2D real-time video analysis software. Agreement between the two computational approaches was assessed using Bland-Altman analysis, Deming regression, and Pearson product-moment correlation. Further, principal component analysis in conjunction with multiple linear regression was used to assess whether individual differences related to the two approaches are due to the waveforms of the acceleration time-series data. Results indicated no mean difference (p > 0.05; d = -0.04) and an extremely large correlation (r = 0.99) between the two approaches. Despite the high agreement, the total error of individual differences was 8.2\% (163.0 N). The individual differences can be explained by a multiple linear regression model (R2adj = 0.86) on principal component scores from the principal component analysis of vertical barbell acceleration time-series waveforms. Findings from this study indicate that the individual errors of force measures can be associated with the inverse dynamic approach. This approach uses vertical barbell acceleration data from video analysis that is prone to error. Therefore, it is recommended to use the work-energy approach to compute mean vertical barbell force as this approach did not rely on vertical barbell acceleration.},
  language  = {en}
}
@article{ChaabeneNegraMoranetal.2021,
  author    = {Chaabene, Helmi and Negra, Yassine and Moran, Jason and Prieske, Olaf and Sammoud, Senda and Ramirez-Campillo, Rodrigo and Granacher, Urs},
  title     = {Plyometric training improves not only measures of linear speed, power, and change-of-direction speed but also repeated sprint ability in young female handball players},
  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    = {8},
  publisher = {Lippincott Williams \& Wilkins},
  address   = {Philadelphia},
  issn      = {1064-8011},
  doi       = {10.1519/JSC.0000000000003128},
  pages     = {2230 -- 2235},
  year      = {2021},
  abstract  = {This study examined the effects of an 8-week plyometric training (PT) program on components of physical fitness in young female handball players. Twenty-one female adolescent handball players were assigned to an experimental group (EG, n = 12; age = 15.9 +/- 0.2 years) or an active control group (CG, n = 9, age = 15.9 +/- 0.3 years). While EG performed plyometric exercises in replacement of some handball-specific drills, CG maintained the regular training schedule. Baseline and follow-up tests were performed for the assessment of linear speed (i.e., 5-, 10-, and 20-m time), change-of-direction (CoD) speed (i.e., T-test time), muscle power (i.e., countermovement jump [CMJ] height and reactive strength index [RSI]), and repeated sprint ability (RSA) (RSA total time [RSA(total)], RSA best time [RSA(best)], and RSA fatigue index [RSA(FI)]). Data were analyzed using magnitude-based inferences. Within-group analyses for the EG revealed moderate-to-large improvements for the 5-m (effect size [ES] = 0.81 [0.1-1.5]), 10-m sprint time (ES = 0.84 [0.1-1.5]), RSI (ES = 0.75 [0.1-1.4]), RSA(FI) (ES = 0.65 [0.0-1.3]), and T-test time (ES = 1.46 [0.7-2.2]). Trivial-to-small ES was observed for RSA(best) (ES = 0.18 [-0.5 to 0.9]), RSA(total) (ES = 0.45 [-0.2 to 1.1]), 20-m sprint time (ES = 0.56 [-0.1 to 1.2]), and CMJ height (ES = 0.57 [-0.1 to 1.3]). For the CG, within-group analyses showed a moderate performance decline for T-test time (ES = -0.71 [-1.5 to 0.1]), small decreases for 5-m sprint time (ES = -0.46 [-1.2 to 0.3]), and a trivial decline for 10-m (ES = -0.10 [-0.9 to 0.7]) and 20-m sprint times (ES = -0.16 [-0.9 to 0.6]), RSA(total) (ES = 0.0 [-0.8 to 0.8]), and RSA(best) (ES = -0.20 [-0.9 to 0.6]). The control group achieved trivial-to-small improvements for CMJ height (ES = 0.10 [-0.68 to 0.87]) and RSI (ES = 0.30 [-0.5 to 1.1]). In conclusion, a short-term in-season PT program, in replacement of handball-specific drills, is effective in improving measures of physical fitness (i.e., linear/CoD speed, jumping, and RSA) in young female handball players.},
  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}
}