ABSTRACT
The purpose of this study was to investigate the relationship among torque, motion of lower limbs during the take-off phase and muscle strength of lower limbs. Subjects were 12 male track and field athletes who had a top record of 6.84±0.41 m. Several variables of the 12 subjects, such as displacement, velocity, angle and angular velocity, and maximum torque of the knee and hip joints during the take-off phase, were obtained from film analysis and measurement of lower limb strength by Biodex.<BR>The main results were as follows:<BR>1. Subjects who had a lower angular velocity of the take-off knee joint after landing showed a lower decreasing ratio of velocity during the takeoff phase.<BR>2. There was a significant relationship between records for the long jump and hip flexion torque of the take-off leg during the last part of the take-off phase (r=-0.678, P<0.05) .<BR>3. Subjects who showed a higher value of hip flexion torque of their free leg during the last part of the take-off phase showed lower take-off angles.<BR>4. There was a significant relationship between knee extension strengths (60, 180, 300 deg/s) and knee joint angles at the middle of the take-off phase (r=0.700 P<0.01, r=0.672 P<0.05, r=0.751 P<0.01) .<BR>5. Subjects who maintained a larger knee angle for their take-off leg indicated a decrease in knee extension torque of their take-off leg during the last part of the take-off phase.<BR>6. Subjects who showed higher hip extension strength made the transition to hip flexion torque of the take-off leg from the middle to the last part of the take-off phase.<BR>From these results, it can be seen that knee extension strength is important for efficient take-off, and hip joint torque is one of the factors that influences one's record in the long jump.