ABSTRACT
The purpose of this study was to investigate the mechanism of the dynamic morphological change of the femoral extensor evoked by contraction.<BR>In this study, the morphological changes during contraction and relaxation of the femoral extensor were analysed using MRI, and, the centers of gravity of the entire extensor group and of each extensor component were calculated using a pattern analyzer. The subjects were 10 female college basketball players, aged 18 to 22 years, with no history of knee injuries.<BR>The results were as follows:<BR>1. The shift of the center of gravity of each component was very characteristic.<BR>2. The greatest dynamic morphological change was observed in the middle of the femoral extensors when the most muscle volume was involved, and the muscles were at their maximal volume.<BR>3. During muscle contraction, obvious anterior protrusion of the muscle belly of each component of the quadriceps femoris was observed. The muscular force may be transferred effectively into the patellar tendon insertion.