Effect of maintained stretch on the range of motion of the human ankle joint

The effectiveness of maintained stretch in expanding the range of motion of the human ankle joint was assessed in a population of normal adults. Controlled movements were imposed upon the ankle, and triceps surae 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 sufficient to distort a subjective assessment of changes in range of motion. For the remaining five subjects, a 60-s maintained stretch produced a small decrease in the torque subsequently generated by an imposed dorsiflexing movement, but this effect was transient and largely disappeared following 300 s of rest at a neutral position. This short-term effect is consistent with the viscoelastic properties of collagenous material stretched during such treatment and is unlikely to lead to long-term increases in range of motion.