Real-time feedback enhances forward propulsion during walking in old adults.
BACKGROUND
Reduced propulsive function during the push-off phase of walking plays a central role in the deterioration of walking ability with age. We used real-time propulsive feedback to test the hypothesis that old adults have an underutilized propulsive reserve available during walking.


METHODS
8 old adults (mean [SD], age: 72.1 [3.9] years) and 11 young adults (age: 21.0 [1.5] years) participated. For our primary aim, old subjects walked: 1) normally, 2) with visual feedback of their peak propulsive ground reaction forces, and 3) with visual feedback of their medial gastrocnemius electromyographic activity during push-off. We asked those subjects to match a target set to 20% and 40% greater propulsive force or push-off muscle activity than normal walking. We tested young subjects walking normally only to provide reference ground reaction force values.


RESULTS
Walking normally, old adults exerted 12.5% smaller peak propulsive forces than young adults (P<0.01). However, old adults significantly increased their propulsive forces and push-off muscle activities when we provided propulsive feedback. Most notably, force feedback elicited propulsive forces that were equal to or 10.5% greater than those of young adults (+20% target, P=0.87; +40% target, P=0.02). With electromyographic feedback, old adults significantly increased their push-off muscle activities but without increasing their propulsive forces.


CONCLUSIONS
Old adults with propulsive deficits have a considerable and underutilized propulsive reserve available during level walking. Further, real-time propulsive feedback represents a promising therapeutic strategy to improve the forward propulsion of old adults and thus maintain their walking ability and independence.
Department of Integrative Physiology, University of Colorado, Boulder, CO 80309-0354, United States; Department of Mechanical Engineering, University of Wisconsin, Madison, WI 53706, United States. Electronic address: jrfranz2@wisc.edu.
Jason R
JR
Franz
Department of Integrative Physiology, University of Colorado, Boulder, CO 80309-0354, United States.
Michela
M
Maletis
Department of Integrative Physiology, University of Colorado, Boulder, CO 80309-0354, United States.
Rodger
R
Kram
D000368:Aged; D004576:Electromyography; D004734:Energy Metabolism; D056228:Feedback, Sensory / Q000502:physiology*; D005260:Female; D005684:Gait / Q000502:physiology; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D016138:Walking / Q000502:physiology*; D055815:Young Adult
Ankle power; Biofeedback; Elderly; Intervention; Rehabilitation