|（School of Physical Education，Anhui Normal University，Wuhu 241000，China）
Abstract: By using the JE-TB0810 8-channel myoelectricity acquisition and test system as well as the ISOMED 2000 isokinetic test and training system, the author performed myoelectricity and isokinetic muscle strength tests respectively on two taekwondo players, so as to determine the major strength exploding muscles, muscle strength using duration, used muscle strength magnitude and muscle strength using harmony with respect to the technical move of backward cross-kicking made by taekwondo players, and secondly, to diagnose the flexion and extension proportion of muscle strength of the hips and knee joints at different moving speeds during the technical move of backward cross-kicking, the percentage of muscle strength of the same muscle group at different sides, and the characteristics of muscle power, which affect the technical move of backward cross-kicking. Via his study the author revealed that in real competitions, for the technical move of backward cross-kicking in which the left foot steps forward while the right foot steps backward, the major strength exploding muscles are the biceps muscle of the right thigh, the gluteus maximus of the left and right buttocks, the rectus muscle of the right thigh, the inner muscle of the left and right thigh, the rectus muscle of the left thigh, and the gastrocnemius muscle. When diagnosing and analyz-ing factors that affect the technical move of backward cross-kicking, the researcher should consider the balance be-tween the active power and the flexion and extension muscle strength of the hips and knee joints, as well as the magnitude of muscle strength and power of the same muscle group at the left and right sides.
Key words: sports biomechanics；taekwondo player；backward cross-kicking；characteristic of muscle strength