Biomechanical Analyses of Shot Putting

[[abstract]]Purposes: The purposes of this study were (1) to analyze the kinematics of spin and glide shot put technique and correlate it with performance. (2) to analyze the ground reaction force and impulse and correlate them with performance. (3) to analyze the moment and power of joints of lower limbs. Methods: Three right-handed male spin shot putters and three glide shot putters were subjects. Four high-speed cameras (125 Hz) were synchronized to sample the motion data and were gen-locked with two force plate forms (1250 Hz) which were set in the middle and front of the circle respectively to sample the ground reaction force. Those data were then digitized and calculated with Kwon 3D and Kwon GRF system to get the parameters. Results: In the aspect of spin technique: There were significant positive correlations between the performance and maximal vertical force, maximal loading rate of vertical force, propulsive phase time, vertical impulse in propulsive phase, total vertical impulse and total horizontal impulse on right leg, and maximal horizontal braking force, total vertical force and total ground reaction force time on left leg. There were significant negative correlations between the performance and the time of maximal horizontal braking force and total horizontal impulse. During the right foot landing, the muscle moment about the ankle was net plantar flexion moment and showed power absorption at first and then power generation; the muscle moment about the knee was net flexion moment and showed power generation at first, and then the net extension moment and showed power absorption and then power generation again; the muscle moment about the hip was net extension moment, and on the frontal plane, was net abduction moment at first in a short time and then net adduction moment latter in long time, and showed power generation at first, and then power absorption, and then power generation again. During the left foot landing, the muscle moment about the ankle was net plantar flexion moment and showed power absorption at first and then power generation; the muscle moment about the knee was net extension moment and showed power generation; the muscle moment about the hip was net flexion moment, and on the frontal plane, was net abduction moment and showed power absorption and then power generation. Conclusions: In the aspect of spin technique: The key phase during right foot support was the propulsive phase. The vertical force was crucial and the braking effect of right foot should be reduced in the phase. The braking effect of left foot was in the opposite direction of the throwing, however it was contributive to the performance and crucial. Moreover, the maximal horizontal braking force should be reached quickly and the vertical impulse should be increased. During right foot support, the ankle joint muscles took charge of cushion at fist and then push; the knee and hip joint muscles took charge of spin and the following cushion, and then push. During left foot support, the ankle and hip joint muscles took charge of cushion at fist and then push; the knee joint muscles took charge of push.