Comparative Study of the Sprint Start Biomechanics of Men’s 100 m Athletes of Different Levels

Background: This study sought to investigate the kinematic and kinetic differences in sprint start between high-level and medium-level sprinters. Methods: Twenty male sprinters were dichotomized according to their personal 100 m performance. Each sprinter performed three block starts. Six high-speed cameras were used for 2D kinematic analysis, and kinematic and dynamic forces were determined by Kisprint. Results: There was no significant differences between high-level and medium-level athletes in the antero-posterior distance of two blocks, block inclination, reaction time, push time, and the joint angle of set position (p > 0.05). The ankle angle of the front leg and swinging leg at the time of front leg exit were significantly greater in high-level athletes than in medium-level athletes (p < 0.05). The vertical RFD (rate of force development) and RFD of high-level athletes were significantly lower than that of medium-level athletes (p < 0.05). The relative maximum horizontal force generated by the front leg of high-level athletes was significantly larger than that of medium-level athletes (p < 0.05), and the maximum vertical force of the rear leg was significantly lower than that of medium-level athletes (p < 0.05). Conclusions: Our finding shows that the start kinematics of high-level sprinters is characterized by a greater ankle angle of the swinging leg and front support leg at the front block exit. High-level sprinters generate greater maximum horizontal force in the front block and smaller maximum vertical force in the rear block.