Short-term effects of an eccentric-overload training program on the physical performance on U-16 elite soccer players

To analyse the effect of an eccentric-overload training program (i.e., lateral squat exercise using a flywheel device) on performance in junior elite soccer players. Sixteen soccer players (14.7 +/- .2 years) were randomly assigned to 2 groups: control group (n=8, CG) and strength group (n=8, SG). The SG complemented soccer training with a proposed eccentric-overload training program 2 days per weeks during 6 weeks. Before and after the training period jumping ability, linear and non-linear sprint and lower-limb power were measured. Substantial improvements (likely to very likely) were found in the SG in CMJ (ES: .46), percent decrement of COD-L (ES: 1.39) and Mean Power (ES: .73) and Peak Power (ES: .65). Between-groups analysis showed greater substantial improvements in SG in relation to CG in CMJ (ES: .79), percent decrement of COD-R (ES: 1.14) and Mean Power (ES: 1.04) and Peak Power (ES: .88). These results suggest that the inclusion of an eccentric-overload training program in soccer training periodization allow the optimization of the specific physical condition of soccer players.