SPRINT AND JUMP TRAINING ON SAND VERSUS GRASS SURFACES: EFFECTS ON THE PHYSICAL PERFORMANCE OF YOUNG SOCCER PLAYERS.

The aims of this study were to: 1) examine the effects of a 6-week sand training program including both sprint and jump exercises on the speed-related and vertical jump performance of elite young soccer players; and 2) compare the changes induced by a sand training scheme with those induced by a similar training program (in terms of volume, intensity, and exercise types) performed on grass. Twenty-four under-20 soccer players were randomly allocated to two training groups, as follows: “sand” (n = 12) or “grass” (n = 12) groups. Athletes performed squat and countermovement jumps, linear sprints, and Zigzag change-of-direction (COD) speed tests at pre-, mid- (after 6 training sessions), and post-intervention (after 12 training sessions). Both groups exhibited similar increases in the vertical jump and Zigzag performance after the 6-week training period (P-values ranging from 0.0001 to 0.025; effect size ranging from 1.05 to 3.78, for main effect of time). No significant changes were detected for the linear sprint velocity for both groups (P-values ranging from 0.079 to 1.00; effect size ranging from 0.07 to 0.65, for main effect of time). In summary, training on sand or grass surfaces resulted in similar improvements in the physical performance of elite young soccer players. This study confirms the current evidence on the effectiveness of both soft and harder training surfaces in improving the sprint and jump performance of team-sport athletes.