Ankle sprains may lead to disabling sequelae such as joint instability and persistent pain. Immobilization with plaster cast may give rise to joint stiffness and muscle atrophy. Twenty patients with acute inversion sprains of the ankle were treated with a "dynamic" orthopaedic brace after a 10-day plaster immobilization. A control group, consisting of 10 subjects, received a weight-bearing short-leg plaster cast for 25 days. A clinical evaluation and an instrumental isokinetic investigation (Cybex) were performed as scheduled. The clinical findings suggest an earlier and more comprehensive functional recovery in the group receiving the "dynamic" brace compared to the casted group. The isokinetic test revealed a statistically significantly better performance for most parameters in the brace group especially regarding the ankle joint invertors.