Architectural characteristics of dominant leg muscles in junior soccer players

The preferential use of dominant over nondominant limbs produces muscle hyp ertrophy in the dominant limb. The purpose of this study was to investigate the architectural characteristics of the muscle that are associated with d ominant leg use in junior soccer players. Fascicle length, pennation angle and muscle thickness of the medial gastrocnemius (MG) were measured by B-mo de ultrasound in 26 junior soccer players [mean (SID) age: 16.5 (0.6) years ] and 20 control college students [age: 18.5 (0.5) years]. Lower leg circum ference and MG muscle thickness were significantly (P<0.05) greater in the soccer players than in the controls. The percent difference (dominant minus non-dominant legs) in muscle thickness and fascicle length were significan tly (P<0.01) larger in the soccer players than in the controls, but the per cent difference in pennation angle was similar between groups. The differen ce (dominant leg minus non-dominant leg) in muscle thickness was significan tly correlated (r=0.55; P<0.05) with the difference in muscle fascicle leng th in the soccer players, but not in the controls (r=0.18). In conclusion, the preferential use of one limb over another, as seen in junior soccer pla yers, results in a greater difference in muscle thickness between the domin ant and non-dominant legs. This difference in muscle size was associated wi th longer fascicle lengths of the dominant leg. Thus, it appears possible t hat fascicle length may be further influenced by physical training in domin ant legs.