OVERCOMING LIMITATIONS IN ELBOW MOVEMENT IN THE PRESENCE OF ANTAGONIST HYPERACTIVITY

Background and Purpose. A traditional perspective on rehabilitation of patients with abnormal muscular hyperactivity presumes that relaxatio n should be facilitated prior to recruitment of antagonists, if effect ive movement about a joint is to occur. The purpose of the study was t o determine the effect of training weak triceps brachii muscles, with hyperactivity present in the opposing biceps brachii muscles, on elbow function in individuals at lease 1 year poststroke. Subjects. Sixteen patients with chronic stroke were randomly assigned to receive electr omyographic biofeedback to retrain the triceps muscle (n=8) or to rece ive conventional movement training (n=8). Methods. Both groups partici pated in 5 baseline and 10 training sessions involving tasks requiring elbow extension. Preintervention and postintervention measurements in cluded elbow extension range of motion, triceps and biceps muscle elec tromyographic activity during performance of elbow extension, resisted elbow extension, and a reaching task. Results. Two-sample t-test resu lts of between-group comparisons for each variable were not significan t. One-sample t-test results of within-group comparisons showed signif icant increases in triceps muscle mean electromyographic activity duri ng two of the three tasks for the feedback group, but not for the nonf eedback group. Passive and active range of motion in both groups incre ased significantly, although biceps muscle co-contraction persisted. C onclusion and Discussion. These results suggest that functional improv ements at the elbow may have been due to biomechanical (peripheral) ra ther than neuromuscular (central) changes about the joint. Furthermore , these preliminary data indicate that patients with stroke may be tra ined to increase movement without first being trained to specifically inhibit hyperactivity in muscles.