Intramuscular pressure in the leg and thigh related to tensile strap force during knee brace wear. An experimental study in man.

The effects of a functional knee brace on intramuscular pressure in the leg and thigh were measured in eight subjects with a mean age of 32 years. Pressures in the tibialis anterior and rectus femoris muscles were recorded without a knee brace and with a brace applied with strap tensile force of 25 N, 50 N, and a force preferred by the subject. External compression caused by the brace significantly increased intramuscular pressures at rest and muscle relaxation pressure during exercise in the leg and thigh muscles. Pressure in the tibialis anterior muscle increased 3 to 10 times, to mean values between 17.5 and 41 mm Hg, depending on the tensile force of the straps used at brace application. Corresponding mean pressure values in the rectus femoris muscle were between 17.5 and 32.5 mm Hg. Mean pressures in the standing subject varied between 37 and 62 mm Hg. Our study showed that intramuscular pressure at rest and muscle relaxation pressure during exercise in the tibialis anterior and the rectus femoris muscles increased significantly in the braced limb. Local blood perfusion pressure in the supine subject decreased significantly, by 16% to 42%, in the compressed muscles.