Children's maximal volitional muscular force, contractile velocity and muscular power are notoriously lower than adults', especially in males (see Blimkie, 1989 for review). Although many of the observed differences can be attributed to differences in body size, these differences persist even when body size is taken into account (Inbar and Bar-Or, 1986; Grosset et aI., 2008). Thus, additional factors, such as muscle fibre composition, or differences in muscle activation pattern must be considered to account for these differences.