Back

Weight-Bearing Exercises for Patellofemoral Pain Syndrome

Scientists continue to look for the cause of patellofemoral pain syndrome (PFPS). Finding the underlying problem could lead to better, more effective treatment.

PFPS is a common cause of knee pain. The patella (kneecap) normally tracks up and down in a groove over the front of the knee. Muscle imbalance may pull the patella away from that groove resulting in PFPS.

Studies so far show mixed findings about the influence of muscle strength, control, and timing. Some researchers report that early activation of the vastus lateralis (VL) may be a key factor.

The quadriceps muscle along the front of the thigh is made up of four sections of muscle. The VL is the section of muscle along the lateral or outside edge of the thigh. When the VL contracts before the vastus medialis oblique (VMO), the patella moves away from the midline and off track. The VMO is the section of the quadriceps muscle located on the inside of the thigh.

This study further investigates neuromuscular control of the hip and knee in patients with PFPS. The effects of weight-bearing exercises on the timing of the VL, VMO, and hip muscle activity are measured. Muscle activity was measured using electromyographic (EMG) readings.

Each subject completed five trials of a stair stepping task. Then they followed a supervised six-week rehab exercise program. At the end of the six weeks, everyone was retested on the stair stepping activity. Changes in EMG readings were recorded and analyzed.

Patients with PFPS had much slower activation of the VMO compared to normal, healthy adults without PFPS (the control group). After training, the VMO contracted sooner int he PFPS group. There was no change in the timing of the VL. The hip muscle tested (gluteus medius) did not change in when it contracted or how long it stayed contracted (duration) during the activity.

The authors say this study supports the use of weight-bearing exercises to decrease pain and improve function for patients with PFPS. A specific rehab program of balance, stretching, and strengthening of hip and knee muscles restored the normal timing of the quadriceps muscle.

Future studies are suggested to test each exercise individually instead of altogether. It's possible that one exercise is more important than the others.

References: Michelle C. Boling, MS, ATC, et al. Outcomes of a Weight-Bearing Rehabilitation Program for Patients Diagnosed with Patellofemoral Pain Syndrome. In Archives of Physical Medicine and Rehabilitation. November 2006. Vol. 87. No. 11. Pp. 1428-1435.

Back