@misc{KibeleClassenMuehlbaueretal.2014,
  author    = {Kibele, Armin and Classen, Claudia and M{\"u}hlbauer, Thomas and Granacher, Urs and Behm, David George},
  title     = {Metastability in plyometric training on unstable surfaces},
  series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  number    = {606},
  issn      = {1866-8364},
  doi       = {10.25932/publishup-42901},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-429013},
  pages     = {13},
  year      = {2014},
  abstract  = {Background In the past, plyometric training (PT) has been predominantly performed on stable surfaces. The purpose of this pilot study was to examine effects of a 7-week lower body PT on stable vs. unstable surfaces. This type of exercise condition may be denoted as metastable equilibrium. Methods Thirty-three physically active male sport science students (age: 24.1 ± 3.8 years) were randomly assigned to a PT group (n = 13) exercising on stable (STAB) and a PT group (n = 20) on unstable surfaces (INST). Both groups trained countermovement jumps, drop jumps, and practiced a hurdle jump course. In addition, high bar squats were performed. Physical fitness tests on stable surfaces (hexagonal obstacle test, countermovement jump, hurdle drop jump, left-right hop, dynamic and static balance tests, and leg extension strength) were used to examine the training effects. Results Significant main effects of time (ANOVA) were found for the countermovement jump, hurdle drop jump, hexagonal test, dynamic balance, and leg extension strength. A significant interaction of time and training mode was detected for the countermovement jump in favor of the INST group. No significant improvements were evident for either group in the left-right hop and in the static balance test. Conclusions These results show that lower body PT on unstable surfaces is a safe and efficient way to improve physical performance on stable surfaces.},
  language  = {en}
}
@article{PrieskeMuehlbauerKruegeretal.2015,
  author    = {Prieske, Olaf and M{\"u}hlbauer, Thomas and Kr{\"u}ger, Tom and Kibele, A. and Behm, David George and Granacher, Urs},
  title     = {Sex-Specific effects of surface instability on drop jump and landing biomechanics},
  series = {International journal of sports medicine},
  volume    = {36},
  journal   = {International journal of sports medicine},
  number    = {1},
  publisher = {Thieme},
  address   = {Stuttgart},
  issn      = {0172-4622},
  doi       = {10.1055/s-0034-1384549},
  pages     = {75 -- 81},
  year      = {2015},
  abstract  = {This study investigated sex-specific effects of surface instability on kinetics and lower extremity kinematics during drop jumping and landing. Ground reaction forces as well as knee valgus and flexion angles were tested in 14 males (age: 23 +/- 2 years) and 14 females (age: 24 +/- 3 years) when jumping and landing on stable and unstable surfaces. Jump height was found to be significantly lower (9 \%, p < 0.001) when drop jumps were performed on unstable vs. stable surface. Significantly higher peak ground reaction forces were observed when jumping was performed on unstable vs. stable surfaces (5 \%, p = 0.022). Regarding frontal plane kinematics during jumping and landing, knee valgus angles were higher on unstable compared to stable surfaces (1932 \%, p < 0.05). Additionally, at the onset of ground contact during landings, females showed higher knee valgus angles than males (222 \%, p = 0.027). Sagittal plane kinematics indicated significantly smaller knee flexion angles (6-35 \%, p < 0.05) when jumping and landing on unstable vs. stable surfaces. During drop jumps and landings, women showed smaller knee flexion angles at ground contact compared to men (27-33 \%, p < 0.05). These findings imply that knee motion strategies were modified by surface instability and sex during drop jumps and landings.},
  language  = {en}
}
@article{LesinskiPrieskeDempsetal.2016,
  author    = {Lesinski, Melanie and Prieske, Olaf and Demps, Marie and Granacher, Urs},
  title     = {Effects of fatigue and surface instability on neuromuscular performance during jumping},
  series = {Der Schmerz : Organ der Deutschen Gesellschaft zum Studium des Schmerzes, der {\~A}-sterreichischen Schmerzgesellschaft und der Deutschen Interdisziplin{\~A}\iren Vereinigung f{\~A}¼r Schmerztherapie},
  volume    = {26},
  journal   = {Der Schmerz : Organ der Deutschen Gesellschaft zum Studium des Schmerzes, der {\~A}-sterreichischen Schmerzgesellschaft und der Deutschen Interdisziplin{\~A}\iren Vereinigung f{\~A}¼r Schmerztherapie},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {0905-7188},
  doi       = {10.1111/sms.12548},
  pages     = {1140 -- 1150},
  year      = {2016},
  abstract  = {It has previously been shown that fatigue and unstable surfaces affect jump performance. However, the combination thereof is unresolved. Thus, the purpose of this study was to examine the effects of fatigue and surface instability on jump performance and leg muscle activity. Twenty elite volleyball players (18 +/- 2 years) performed repetitive vertical double-leg box jumps until failure. Before and after a fatigue protocol, jump performance (i.e., jump height) and electromyographic activity of selected lower limb muscles were recorded during drop jumps (DJs) and countermovement jumps (CMJs) on a force plate on stable and unstable surfaces (i.e., balance pad on top of force plate). Jump performance (3-7\%; P < 0.05; 1.14 <= d <= 2.82), and muscle activity (2-27\%; P < 0.05; 0.59 <= d <= 3.13) were lower following fatigue during DJs and CMJs, and on unstable compared with stable surfaces during DJs only (jump performance: 8\%; P < 0.01; d = 1.90; muscle activity: 9-25\%; P < 0.05; 1.08 <= d <= 2.54). No statistically significant interactions of fatigue by surface condition were observed. Our findings revealed that fatigue impairs neuromuscular performance during DJs and CMJs in elite volleyball players, whereas surface instability affects neuromuscular DJ performance only. Absent fatigue x surface interactions indicate that fatigue-induced changes in jump performance are similar on stable and unstable surfaces in jump-trained athletes.},
  language  = {en}
}
@article{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{NegraChaabeneSammoudetal.2017,
  author    = {Negra, Yassine and Chaabene, Helmi and Sammoud, Senda and Bouguezzi, Raja and Mkaouer, Bessem and Hachana, Younes and Granacher, Urs},
  title     = {EFFECTS OF PLYOMETRIC TRAINING ON COMPONENTS OF PHYSICAL FITNESS IN PREPUBERAL MALE SOCCER ATHLETES: THE ROLE OF SURFACE INSTABILITY},
  series = {Journal of strength and conditioning research : the research journal of the NSCA},
  volume    = {31},
  journal   = {Journal of strength and conditioning research : the research journal of the NSCA},
  publisher = {Lippincott Williams \& Wilkins},
  address   = {Philadelphia},
  issn      = {1064-8011},
  pages     = {3295 -- 3304},
  year      = {2017},
  abstract  = {Previous studies contrasted the effects of plyometric training (PT) conducted on stable vs. unstable surfaces on components of physical fitness in child and adolescent soccer players. Depending on the training modality (stable vs. unstable), specific performance improvements were found for jump (stable PT) and balance performances (unstable PT). In an attempt to combine the effects of both training modalities, this study examined the effects of PT on stable surfaces compared with combined PT on stable and unstable surfaces on components of physical fitness in prepuberal male soccer athletes. Thirty-three boys were randomly assigned to either a PT on stable surfaces (PTS; n = 17; age = 12.1 +/- 0.5 years; height = 151.6 +/- 5.7 cm; body mass = 39.2 +/- 6.5 kg; and maturity offset = 22.3 +/- 0.5 years) or a combined PT on stable and unstable surfaces (PTC; n = 16; age = 12.2 +/- 0.6 years; height = 154.6 +/- 8.1 cm; body mass = 38.7 +/- 5.0 kg; and maturity offset = 22.2 +/- 0.6 years). Both intervention groups conducted 4 soccer-specific training sessions per week combined with either 2 PTS or PTC sessions. Before and after 8 weeks of training, proxies of muscle power (e.g., countermovement jump [CMJ], standing long jump [SLJ]), muscle strength (e.g., reactive strength index [RSI]), speed (e.g., 20-m sprint test), agility (e.g., modified Illinois change of direction test [MICODT]), static balance (e.g., stable stork bal-ance test [SSBT]), and dynamic balance (unstable stork balance test [USBT]) were tested. An analysis of covariance model was used to test between-group differences (PTS vs. PTC) at posttest using baseline outcomes as covariates. No significant between-group differences at posttest were observed for CMJ (p > 0.05, d = 0.41), SLJ (p > 0.05, d = 0.36), RSI (p > 0.05, d = 0.57), 20-m sprint test (p > 0.05, d = 0.06), MICODT (p > 0.05, d = 0.23), and SSBT (p > 0.05, d = 0.20). However, statistically significant between-group differences at posttest were noted for the USBT (p < 0.01, d = 1.49) in favor of the PTC group. For most physical fitness tests (except RSI), significant pre-to-post improvements were observed for both groups (p < 0.01, d = 0.55-3.96). Eight weeks of PTS or PTC resulted in similar performance improvements in components of physical fitness except for dynamic balance. From a performance-enhancing perspective, PTC is recommended for pediatric strength and conditioning coaches because it produced comparable training effects as PTS on proxies of muscle power, muscle strength, speed, agility, static balance, and additional effects on dynamic balance.},
  language  = {en}
}
@misc{RamirezCampilloGarciaPinillosGarciaRamosetal.2018,
  author    = {Ramirez-Campillo, Rodrigo and Garc{\´i}a-Pinillos, Felipe and Garc{\´i}a-Ramos, Amador and Yanci, Javier and Gentil, Paulo and Chaabene, Helmi and Granacher, Urs},
  title     = {Effects of Different Plyometric Training Frequencies on Components of Physical Fitness in Amateur Female Soccer Players},
  series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  number    = {474},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-419377},
  pages     = {11},
  year      = {2018},
  abstract  = {Plyometric jump training (PJT) is a frequently used and effective means to improve amateur and elite soccer players' physical fitness. However, it is unresolved how different PJT frequencies per week with equal overall training volume may affect training-induced adaptations. Therefore, the aim of this study was to compare the effects of an in-season 8 week PJT with one session vs. two sessions per week and equal training volume on components of physical fitness in amateur female soccer players. A single-blind randomized controlled trial was conducted. Participants (N = 23; age, 21.4 ± 3.2 years) were randomly assigned to a one session PJT per-week (PJT-1, n = 8), two sessions PJT per-week (PJT-2, n = 8) or an active control group (CON, n = 7). Before and after training, participants performed countermovement jumps (CMJ), drop-jumps from a 20-cm drop-height (DJ20), a maximal kicking velocity test (MKV), the 15-m linear sprint-time test, the Meylan test for the assessment of change of direction ability (CoDA), and the Yo-Yo intermittent recovery endurance test (Yo-YoIR1). Results revealed significant main effects of time for the CMJ, DJ20, MKV, 15-m sprint, CoDA, and the Yo-YoIR1 (all p < 0.001; d = 0.57-0.83). Significant group × time interactions were observed for the CMJ, DJ20, MKV, 15-m sprint, CoDA, and the Yo-YoIR1 (all p < 0.05; d = 0.36-0.51). Post-hoc analyses showed similar improvements for PJT-1 and PJT-2 groups in CMJ (Δ10.6\%, d = 0.37; and Δ10.1\%, d = 0.51, respectively), DJ20 (Δ12.9\%, d = 0.47; and Δ13.1\%, d = 0.54, respectively), MKV (Δ8.6\%, d = 0.52; and Δ9.1\%, d = 0.47, respectively), 15-m sprint (Δ8.3\%, d = 2.25; and Δ9.5\%, d = 2.67, respectively), CoDA (Δ7.5\%, d = 1.68; and Δ7.4\%, d = 1.16, respectively), and YoYoIR1 (Δ10.3\%, d = 0.22; and Δ9.9\%, d = 0.26, respectively). No significant pre-post changes were found for CON (all p > 0.05; Δ0.5-4.2\%, d = 0.03-0.2). In conclusion, higher PJT exposure in terms of session frequency has no extra effects on female soccer players' physical fitness development when jump volume is equated during a short-term (i.e., 8 weeks) training program. From this, it follows that one PJT session per week combined with regular soccer-specific training appears to be sufficient to induce physical fitness improvements in amateur female soccer players.},
  language  = {en}
}
@article{RamirezCampilloGarciaPinillosGarciaRamosetal.2018,
  author    = {Ramirez-Campillo, Rodrigo and Garc{\´i}a-Pinillos, Felipe and Garc{\´i}a-Ramos, Amador and Yanci, Javier and Gentil, Paulo and Chaabene, Helmi and Granacher, Urs},
  title     = {Effects of Different Plyometric Training Frequencies on Components of Physical Fitness in Amateur Female Soccer Players},
  series = {Frontiers in Physiology},
  volume    = {9},
  journal   = {Frontiers in Physiology},
  publisher = {Frontiers Media},
  address   = {Lausanne},
  issn      = {1664-042X},
  doi       = {10.3389/fphys.2018.00934},
  pages     = {1 -- 11},
  year      = {2018},
  abstract  = {Plyometric jump training (PJT) is a frequently used and effective means to improve amateur and elite soccer players' physical fitness. However, it is unresolved how different PJT frequencies per week with equal overall training volume may affect training-induced adaptations. Therefore, the aim of this study was to compare the effects of an in-season 8 week PJT with one session vs. two sessions per week and equal training volume on components of physical fitness in amateur female soccer players. A single-blind randomized controlled trial was conducted. Participants (N = 23; age, 21.4 ± 3.2 years) were randomly assigned to a one session PJT per-week (PJT-1, n = 8), two sessions PJT per-week (PJT-2, n = 8) or an active control group (CON, n = 7). Before and after training, participants performed countermovement jumps (CMJ), drop-jumps from a 20-cm drop-height (DJ20), a maximal kicking velocity test (MKV), the 15-m linear sprint-time test, the Meylan test for the assessment of change of direction ability (CoDA), and the Yo-Yo intermittent recovery endurance test (Yo-YoIR1). Results revealed significant main effects of time for the CMJ, DJ20, MKV, 15-m sprint, CoDA, and the Yo-YoIR1 (all p < 0.001; d = 0.57-0.83). Significant group × time interactions were observed for the CMJ, DJ20, MKV, 15-m sprint, CoDA, and the Yo-YoIR1 (all p < 0.05; d = 0.36-0.51). Post-hoc analyses showed similar improvements for PJT-1 and PJT-2 groups in CMJ (Δ10.6\%, d = 0.37; and Δ10.1\%, d = 0.51, respectively), DJ20 (Δ12.9\%, d = 0.47; and Δ13.1\%, d = 0.54, respectively), MKV (Δ8.6\%, d = 0.52; and Δ9.1\%, d = 0.47, respectively), 15-m sprint (Δ8.3\%, d = 2.25; and Δ9.5\%, d = 2.67, respectively), CoDA (Δ7.5\%, d = 1.68; and Δ7.4\%, d = 1.16, respectively), and YoYoIR1 (Δ10.3\%, d = 0.22; and Δ9.9\%, d = 0.26, respectively). No significant pre-post changes were found for CON (all p > 0.05; Δ0.5-4.2\%, d = 0.03-0.2). In conclusion, higher PJT exposure in terms of session frequency has no extra effects on female soccer players' physical fitness development when jump volume is equated during a short-term (i.e., 8 weeks) training program. From this, it follows that one PJT session per week combined with regular soccer-specific training appears to be sufficient to induce physical fitness improvements in amateur female soccer players.},
  language  = {en}
}
@article{PrieskeChaabenePutaetal.2019,
  author    = {Prieske, Olaf and Chaabene, Helmi and Puta, Christian and Behm, David George and B{\"u}sch, Dirk and Granacher, Urs},
  title     = {Effects of Drop Height on Jump Performance in Male and Female Elite Adolescent Handball Players},
  series = {International journal of sports physiology and performance},
  volume    = {14},
  journal   = {International journal of sports physiology and performance},
  number    = {5},
  publisher = {Human Kinetics Publ.},
  address   = {Champaign},
  issn      = {1555-0265},
  doi       = {10.1123/ijspp.2018-0482},
  pages     = {674 -- 680},
  year      = {2019},
  abstract  = {Purpose: To examine the effects of drop height on drop-jump (DJ) performance and on associations between DJ and horizontal-jump/sprint performances in adolescent athletes. Methods: Male (n = 119, 2.5 [0.6] y post-peak-height velocity) and female (n = 120, 2.5 [0.5] y post-peak-height velocity) adolescent handball players (national level) performed DJs in randomized order using 3 drop heights (20, 35, and 50 cm). DJ performance (jump height, reactive strength index [RSI]) was analyzed using the Optojump Next system. In addition, correlations were computed between DJ height and RSI with standing-long-jump and 20-m linear-sprint performances. Results: Statistical analyses revealed medium-size main effects of drop height for DJ height and RSI (P <.001, 0.63 <= d <= 0.71). Post hoc tests indicated larger DJ heights from 20 to 35 and 35 to 50 cm (P <=.031, 0.33 <= d <= 0.71) and better RSI from 20- to 35-cm drop height (P <.001, d = 0.77). No significant difference was found for RSI between 35- and 50-cm drop height. Irrespective of drop height, associations of DJ height and RSI were small with 5-m-split time (-.27 <= r <=.05), medium with 10-m-split time (-.44 <= r <=.14), and medium to large with 20-m sprint time and standing-long-jump distance (-.57 <= r <=.22). Conclusions: The present findings indicate that, irrespective of sex, 35-cm drop heights are best suited to induce rapid and powerful DJ performance (ie, RSI) during reactive strength training in elite adolescent handball players. Moreover, training-related gains in DJ performance may at least partly translate to gains in horizontal jump and longer sprint distances (ie, >= 20-m) and/or vice versa in male and female elite adolescent athletes, irrespective of drop height.},
  language  = {en}
}
@article{NegraChaabeneSammoudetal.2020,
  author    = {Negra, Yassine and Chaabene, Helmi and Sammoud, Senda and Prieske, Olaf and Moran, Jason and Ramirez-Campillo, Rodrigo and Nejmaoui, Ali and Granacher, Urs},
  title     = {The increased effectiveness of loaded versus unloaded plyometric jump training in improving muscle power, speed, change of direction, and kicking-distance performance in prepubertal male soccer players},
  series = {International journal of sports physiology and performance : IJSSP},
  volume    = {15},
  journal   = {International journal of sports physiology and performance : IJSSP},
  number    = {2},
  publisher = {Human Kinetics},
  address   = {Champaign, Ill.},
  issn      = {1555-0265},
  doi       = {10.1123/ijspp.2018-0866},
  pages     = {189 -- 195},
  year      = {2020},
  abstract  = {Purpose: To examine the effects of loaded (LPJT) versus unloaded plyometric jump training (UPJT) programs on measures of muscle power, speed, change of direction (CoD), and kicking-distance performance in prepubertal male soccer players. Methods: Participants (N = 29) were randomly assigned to a LPJT group (n = 13; age = 13.0 [0.7] y) using weighted vests or UPJT group (n = 16; age = 13.0 [0.5] y) using body mass only. Before and after the intervention, tests for the assessment of proxies of muscle power (ie, countermovement jump, standing long jump); speed (ie, 5-, 10-, and 20-m sprint); CoD (ie, Illinois CoD test, modified 505 agility test); and kicking-distance were conducted. Data were analyzed using magnitude-based inferences. Results: Within-group analyses for the LPJT group showed large and very large improvements for 10-m sprint time (effect size [ES] = 2.00) and modified 505 CoD (ES = 2.83) tests, respectively. For the same group, moderate improvements were observed for the Illinois CoD test (ES = 0.61), 5- and 20-m sprint time test (ES = 1.00 for both the tests), countermovement jump test (ES = 1.00), and the maximal kicking-distance test (ES = 0.90). Small enhancements in the standing long jump test (ES = 0.50) were apparent. Regarding the UPJT group, small improvements were observed for all tests (ES = 0.33-0.57), except 5- and 10-m sprint time (ES = 1.00 and 0.63, respectively). Between-group analyses favored the LPJT group for the modified 505 CoD (ES = 0.61), standing long jump (ES = 0.50), and maximal kicking-distance tests (ES = 0.57), but not for the 5-m sprint time test (ES = 1.00). Only trivial between-group differences were shown for the remaining tests (ES = 0.00-0.09). Conclusion: Overall, LPJT appears to be more effective than UPJT in improving measures of muscle power, speed, CoD, and kicking-distance performance in prepubertal male soccer players.},
  language  = {en}
}
@article{NegraChaabeneFernandezFernandezetal.2020,
  author    = {Negra, Yassine and Chaabene, Helmi and Fernandez-Fernandez, Jaime and Sammoud, Senda and Bouguezzi, Raja and Prieske, Olaf and Granacher, Urs},
  title     = {Short-term plyometric Jump training improves repeated-sprint ability in prepuberal male soccer players},
  series = {Journal of strength and conditioning research : the research journal of the NSCA},
  volume    = {34},
  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.0000000000002703},
  pages     = {3241 -- 3249},
  year      = {2020},
  abstract  = {This study examined the effects of a short-term (i.e., 8 weeks) combined horizontal and vertical plyometric jump training (PJT) program in combination with regular soccer-specific training as compared with soccer-specific training only on jump and change of direction (CoD) performances, speed, and repeated-sprint ability (RSA) in prepuberal male soccer players. Twenty-four players were recruited and randomly assigned to either a PJT group (PJT(G); n = 13; 12.7 +/- 0.2 years) or an active control group (CONG; n = 11; 12.7 +/- 0.2 years). The outcome measures included tests for the assessment of jump performance (drop jump from 20- to 40-cm height [DJ20 and DJ40] and 3-hop test [THT]), speed (20-m sprint), CoD (T-test), and RSA (20-m repeated shuttle sprint). Data were analyzed using magnitude-based inferences. Within-group analyses revealed large performance improvements in the T-test (d = -1.2), DJ20 (d = 3.7), DJ40 (d = 3.6), THT (d = 0.6), and the RSA(total) (d = -1.6) in the PJT(G). Between-group analyses showed greater performance improvements in the T-test (d = -2.9), 20-m sprint time (d = -2.0), DJ20 (d = 2.4), DJ40 (d = 2.0), THT (d = 1.9), RSA(best) (d = -1.9), and the RSA(total) (d = -1.9) in the PJT(G) compared with CONG. Eight weeks of an in-season PJT in addition to regular soccer-specific training induced larger increases in measures of physical fitness in prepuberal male soccer players compared with regular soccer-specific training only. More specifically, PJT was effective in improving RSA performance.},
  language  = {en}
}