The purpose of this study was to investigate the cross-sectional development characteristics of body composition, lower-leg multi-joint power output and sprint running in non-elite junior and youth soccer players. The leg extension power, counter-movement vertical jump (CMJ), and 30m-sprint time for eighty male soccer players aged 13.8-18.1 yrs were measured. Junior and youth soccer players were compared with sedentary normal identical aged boys. Statistical analysis was used by one-way ANOVA and multiple comparisons of variance were performed on the basis of the Tukey-Kramer HSD test. Statistical significance was accepted at level of p < 0.05. Relative increases from 14 yrs to 18 yrs players were significantly (p < 0.05) indicated; body height (7.7%), leg extension power (87.8%), CMJ (35.3%), 30m-sprint (8.7%). 10m-sprint time was negatively correlated with both leg extension power (r = -0.52) and CMJ (r = -0.60). Comparison of relative values of increase from 14 to 18 yrs in junior and youth soccer players to those in sedentary normal boys were as follows; 2.3 (body height), 2.5 (leg extension power), 3.0 (CMJ), 2.1 (sprint ability). It might be suggested that consistent regular soccer training from junior and youth aged might prompt developmental gains not only largely for lower-leg multi-joint power but also not a little for sprint ability.
