Effects of a Functional Knee Brace on Leg Muscle Function

Abstract

The effects of a functional knee brace on local intra muscular pressures and on calculated blood perfusion pressure in the tibialis anterior muscle of the legs of six volunteers were determined. Torque generation during dorsiflexion of the ankle joint was measured with a Ki netic Computerized ergometer, and the time to elicit muscle fatigue during exercise was recorded. For each experimental subject studies compared right with left unbraced legs, then right braced with left unbraced legs, and finally right unbraced with left braced legs. In the braced leg, intramuscular pressure at rest and muscle relaxation pressure during exercise were significantly higher, and the time to elicit muscle fatigue was 35% shorter. The calculated local blood perfusion pressure was lower because of the increased muscle relaxation pressure. We conclude that the increased muscle re laxation pressure during exercise caused by a knee brace is a possible explanation for the premature development of muscle fatigue in the braced leg.