Objective: To assess the stretch of pronator muscles produced by a specifically designed upper-limb Lycra garment that could have a better acceptability than rigid splints in treating upper-limb spasticity. Design: Double-blind comparison among three garments. They were designed to produce a supinating, a pronating, and no torsional three, and were individually manufactured and tested in 10 healthy volunteers. Main Outcome Measure: Angular position and passive rotational stiffness of the forearm were measured with and without each of the garments immediately after the garment was fitted and every hour for 6 hours. Results: When put on by a trained person, the supinator garment supinated the forearm In all subjects (mean, 17 degrees; p < .01; range, 5 degrees to 44 degrees) while the pronator garment pronated the forearm in 8 of 10 subjects (mean, 5 degrees; p < .01). These effects gradually decayed over 6 hours, as garment position was not readjusted, Passive rotational stiffness of the forearm increased by about 30% with each type of garment. The garments designed to produce no torsional force exerted no intrinsic relational effect. Conclusion: individually made Lycra garments can produce continuous stretch of muscles for several hours and may be useful in the treatment of spasticity, The garments, however, must be put on by a trained person and their position adjusted when necessary. (C) 1997 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation.