Knee Flexor and Extensor Strength and Functional Performance in Elite High-school Basketball Players. Possible Cause of Anterior Cruciate Ligament Injuries.

We evaluated knee flexor and extensor strength and functional performance of high-school basketball players of the 1993 national champion teams. Ten males and ten females (mean age, 16.9 years and 16.8 years, respectively), who had no previous knee injuries, were examined.Muscle strensth was assessed by measuring peak torque during concentric, eccentric, and isometric muscle actions using a MYORET isokinetic testing device. Muscle strength per body weight of the male players was always greater than that of the female players. However, when isokinetic muscle strength was divided by isometric muscle strength for standardization, the eccentric quadriceps strength of female players became greater than that of the males.It was suggested that female players can utilize their eccentric quadriceps muscle action for bounce motion before jumping-up and for shock absorption at landing. On the other hand, the eccentric quadriceps contraction causes an anterior-drawing force onto tieir tibial tubercles at the time of landing, and this might be a possible cause of non-contact type ACL injuries which frequently occur in female basketball players.