Patellofemoral pain syndrome (PFPS) of the knee has been treated successfully with foot orthotics. These shoe inserts correct the foot position. They help the quadriceps (thigh) muscle work better. In this study three groups of adults were studied. Muscle activity was measured while using orthotics.
Each group had a different natural foot position. Some of the subjects had a flat foot. Others had a high arch. The effects of four orthotic postings were measured on three upper leg muscles. Changing the tilt of the insert is called posting.
Electrical activity of each muscle was measured. Activities included a single-leg squat, lateral step-down, and vertical jump. In one set of exercises, no orthotic was used. Three other trials were done using different orthotic postings. There are very few studies on the effects of orthotic postings on leg muscle activity.
The authors report natural foot position doesn’t seem to have any effect on muscle activity during the exercises described. Muscle activity increased with any orthotic used. The results were the same for all postings. Changes in muscle activity were seen in the squat and step down activities, but not during the vertical jump.
Increasing the right muscle activity helps patients with PFPS. The muscles keep the kneecap tracking normally. More research is needed on the effects of orthotics on muscle activity. This information may be helpful in treating PFPS.