The aim of this study is to investigate the effects of the competitive season on isokinetic muscular parameters of the lower limbs in world-class handball players. Nineteen, male, world-class, handball players (age, 26.6 ± 5.4 years) participated in the study. Two bilateral isokinetic tests of knee joint flexors (H; hamstring) and extensors (Q; quadriceps) were performed in the beginning and end of the competitive season to determine the peak torque (PT), the mean power, and agonist-antagonist ratio, dominant-nondominant ratio (DNDR), and combined ratio. The results showed a significant decrease in PT values at low angular velocity (60°·s?1) in concentric mode for Q on dominant leg (p < 0.001). The other PT values for dominant and nondominant legs at low and high angular velocities (240°/s) and in eccentric mode (30°/s) were not significantly different for Q and H. For mean power, values did not change at 60°/s. At 240°/s, we found a significant decrease in H for dominant leg (p < 0.001) but not for nondominant leg. In eccentric mode, the results showed a significant increase on both legs (p < 0.001). For the ratios, values significantly decreased for DNDR at 6°/s for Q (p < 0.03) and for agonist/antagonist ratio at 240°/s for the dominant leg (p < 0.01). The present results highlight the importance of integrating regular strength training sessions during the competitive season in world-class handball players. Accordingly, this study should help trainers to modify their planning to maximize strength and power qualities of the lower limbs of their players in addition to avoiding injuries.The aim of this study was to assess the effect of an 8-week repeated sprint with change of direction (RS-COD) training program on RS, intermittent endurance, and change of direction performance in youth soccer players with different aerobic fitness levels. Athletes were randomly assigned into a soccer-only (n = 9; age, 14.9 ± 0.4 years) and soccer plus RS-COD training programs for players with high (n = 10; age, 14.4 ± 0.5 years) and low (n = 10; age, 14.4 ± 0.5 years) aerobic fitness. Repeated sprint with change of direction was completed 2 days per week, involving 3 sets of ten 18-m sprints with 2 changes of direction of 90°. The soccer-only group achieved greater improvements in intermittent endurance (effect size [ES] = 0.61) and sprint decrement during RS ability test (ES = 0.77) compared with the RS-COD groups (ES = 0.19-0.24; ES = 0.27 to 0.02; respectively). Repeated sprint with change of direction training improved RS (ES = 0.16-0.38) and change of direction (ES = 0.48) performance in high but not in low-fitness players (ES = 0.03-0.13; ES = 0.16; respectively). Moreover, improvements in RS and change of direction were (possibly) greater in high compared with low fitness and soccer-only trained players (possibly to very likely). In conclusion, although RS-COD training may positively affect RS and change of direction performance, its effects may vary according to the initial aerobic fitness of youth soccer players, with trivial effect on intermittent endurance in high-aerobic fitness players and possible beneficial effect on low-aerobic fitness players.
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