RESUMO
OBJECTIVE: To compare performance error and perceived difficulty during toe-out gait modification in people with knee osteoarthritis (OA) across 3 different types of visual feedback: mirror, raw video, and real-time biofeedback of toe-out angle. DESIGN: Repeated-measures, within-subject trial. SETTING: University motion analysis laboratory. PARTICIPANTS: Individuals with knee OA (N=20; 11 women; mean age, 65.4±9.8y) participated in this study. Seven participants had mild knee OA, 9 had moderate knee OA, and 4 had severe knee OA. INTERVENTIONS: Participants were trained to walk on a treadmill while matching a target indicating a 10° increase in stance phase toe-out compared with toe-out angle measured during self-selected walking. The target was provided visually via the 3 types of feedback listed above and were presented in a random order. MAIN OUTCOME MEASURES: Kinematic data were collected and used to calculate the difference between the target angle and the actual performed angle for each condition (toe-out performance error). Difficulty was assessed using a numerical rating scale (0-10) provided verbally by participants. RESULTS: Toe-out performance error was significantly less when using the real-time biofeedback method than when using the other 2 methods (P=.025; mean difference vs mirror=2.05°; mean difference vs raw video=1.51°). Perceived difficulty was not statistically different between the groups (P=.51). CONCLUSIONS: Although statistically significant, the 2° difference in toe-out gait performance error may not necessitate the large economic and personnel costs of real-time biofeedback as a means to modify movement in clinical or research settings.