The American journal of sports medicine
-
Reflex response times of the vastus medialis obliquus and vastus lateralis were evaluated in 41 normal subjects and 16 patients with extensor mechanism dysfunction. The reflex response times for both muscles to a patellar tendon tap were evaluated by electromyography. The latencies of the muscles were statistically analyzed in both groups. ⋯ This increase in vastus lateralis reflex response time may indicate a motor control problem in the patient with extensor mechanism dysfunction. Results indicate that there is a reversal of the normal muscular firing order between the two muscles in these patients. Patients with extensor mechanism dysfunction may be demonstrating a neurophysiologic motor control imbalance that may account for or contribute to their anterior knee pain.