Effectiveness of mechanical energy utilization during lifting phase of squat

The purpose of this study was to examine relationship between kinetics and effectiveness of mechanical energy utilization during lifting phase of squat. Ten male students majoring physical education. Participants completed one repetition of a high-bar back squat using 75% of 1RM. Sagittal plane kinematics were recorded using a high-speed camera at 120 fps and analysed using Frame-DIAS Ⅴ. Ground reaction force was measured using a force platform at a frequency of 1,000 Hz. Effectiveness index of mechanical energy utilization (EI) was calculated as changes of potential energy from lowest point to highest point divided by mechanical work. Angular impulse of the knee joint was significantly correlated positively with EI, although net angular impulse of the hip joint was significantly correlated negatively with EI. Greater force production of the knee joint may be one of factors to improve effectiveness of mechanical energy utilization during squat.