Functional knee braces increase intramuscular pressures in the anterior compartment of the leg

The effect of three different functional knee braces on intramuscular pressures in the anterior compartment of the leg was investigated in 8 healthy subjects. Pres sures were recorded with the microcapillary infusion technique while the subjects were either supine, sitting, or standing. Pressures at rest in the anterior tibial muscle increased significantly following application of each of the three knee braces regardless of posture. Similarly, muscle relaxation pressure during exercise also increased significantly on brace application. A pres sure of 40 mm Hg was exceeded in 9 of 18 intramus cular pressure measurements with the subject stand ing. The tested functional knee braces increased mus cle pressures at rest and muscle relaxation pressure during exercise to levels that, according to other stud ies, might decrease muscle blood flow significantly. External compression from a knee brace on leg muscles might, therefore, induce premature muscle fatigue be cause of local insufficient perfusion of the working muscle.