Reduction of muscular hypertonus by long-term muscle stretch.

In 10 patients with spastic paraparesis, the effect of long-term stretch on hip adductor muscle tone was studied. Stretch was accomplished by using a mechanical leg-abductor device giving individually adjusted adductor muscle stretch in single or repeated 30 min periods. The effect on muscle tone was estimated from surface EMG activity and by range of voluntary and passive hip abduction. The passive movements were obtained by an individually adjusted constant pulling force. After a single session of stretch, range of voluntary hip abduction increased 3 to 16 degrees (average 85%). Range of passive movement increased 1 to 9 degrees (average 23%). After repeated stretch periods in a home program (4 patients), range of voluntary hip abduction increased 5 to 22 degrees (average 255%). Range of passive movements increased 6 to 12 degrees (average 48%). In all patients studied the co-activation of the antagonists in voluntary hip abduction was reduced after a stretch session.