The effect of volleyball playing on the knee extensor mechanism.

The knee extensor mechanism was examined in 32 male competitive volleyball players (Group V) and in a control group of 49 young adult males (Group C) to evaluate the effects of previous jumping activity on the knee extensor mechanism. Several variables were recorded by means of a structured questionnaire, and by clinical and radiographic examination. The amount of physical activity from the age of 7 years onward was significantly greater in Group V than in Group C. The incidence of anterior knee pain during the year preceding the examination was higher in Group V (31%) than in Group C (6%; P less than 0.01). The most common reason for anterior knee pain in Group V was so-called "jumper's knee." No significant difference between the groups was found in the incidence of clinical symptoms and signs of patellar chondromalacia. There were radiologically detectable soft tissue calcifications at the upper or lower pole of the patella or anterior to the patella in 38% of the subjects in Group V, but no such calcifications were seen in Group C (P less than 0.001). However, persistent symptoms did not correlate with the calcifications. Group V subjects had a slight but significant trend to patella alta when compared to Group C (P less than 0.05) according to the Blackburne and Peel index.