EFFECT OF MAINTAINED STRETCH ON THE RANGE OF MOTION OF THE HUMAN ANKLE JOINT

The effectiveness of maintained stretch in expanding the range of moti on of the human ankle joint was assessed in a population of normal adu lts. Controlled movements were imposed upon the ankle, and triceps sur ae and tibialis anterior electromyograms were monitored to ensure that only passive joint properties generated ankle torque. We found that a majority of subjects (7 of 12) showed evidence of muscle activity suf ficient to distort a subjective assessment of changes in range of moti on. For the remaining five subjects, a 60-s maintained stretch produce d a small decrease in the torque subsequently generated by an imposed dorsiflexing movement, but this effect was transient and largely disap peared following 300 s of rest at a neutral position. This short-term effect is consistent with the viscoelastic properties of collagenous m aterial stretched during such treatment and is unlikely to lead to lon g-term increases in range of motion.