Sammoud, SNegra, YBouguezzi, RUthoff, AMoran, JChaabene, H2026-03-232026-03-232026-02-27Frontiers in Sports and Active Living, ISSN: 2624-9367 (Print); 2624-9367 (Online), Frontiers Media SA, 8, 1717594-. doi: 10.3389/fspor.2026.17175942624-93672624-9367http://hdl.handle.net/10292/20795Introduction: This study aimed to examine the effects of combined Nordic Hamstring and Reverse Nordic exercises on measures of physical fitness in prepubertal male soccer players. Methods: The eccentric training program lasted 8 weeks, with two sessions per week, each lasting approximately 20 min and performed immediately after the warm-up of regular soccer training. A total of 34 prepubertal male soccer players were recruited and randomly assigned at the group level to either the eccentric training group (n = 17; age = 12.44 ± 0.24 years, maturity offset = −1.27 ± 0.28) or the active control group (n = 17; age = 12.40 ± 0.22 years, maturity offset = −1.15 ± 0.35). Physical fitness was assessed through measures of linear sprint performance (10 & 20 m), change of direction (505 test), agility (Y-shaped agility test), and vertical (countermovement jump) and horizontal jump performance (standing long jump). Results and discussion: The findings showed moderate group-by-time interactions for all fitness measures [effect size (d) = 0.62–1.16]. Post hoc analyses revealed small-to-moderate improvements in the eccentric training group across all performance measures (d = 0.31–1.18), while no significant changes were observed in the control group for any fitness measure. In conclusion, our findings support the effectiveness, practicality, and safety (no injuries reported) of the eccentric training program for improving physical fitness in prepubertal male soccer players.© 2026 Sammoud, Negra, Bouguezzi, Uthoff, Moran and Chaabene. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.42 Health Sciences4207 Sports Science and ExerciseClinical ResearchClinical Trials and Supportive Activities4207 Sports science and exerciseathletic performancebiological ageeccentric trainingteam sportsyouth developmentJournal ArticleOpenAccess10.3389/fspor.2026.1717594