Effect of light finger touch on postural sway after lower-limb muscular fatigue.

OBJECTIVE: To investigate whether a light finger touch can compensate for the increased postural sway induced by lower-limb muscular fatigue. DESIGN: Before-after trials. SETTING: General community. PARTICIPANTS: Nine healthy university students (mean age, 23.8+/-2.6y; mean body weight, 72.7+/-6.9 kg; mean height, 177.2+/-7.5 cm). INTERVENTIONS: Participants stood with their feet together and eyes closed. They were asked to sway as little as possible in 4 conditions: no fatigue/no touch, no fatigue/touch, fatigue/no touch, and fatigue/touch. Calf muscle fatigue was induced by having participants stand on their toes until exhaustion. Touch conditions involved a gentle light touch with the right index finger on a nearby surface at waist height. MAIN OUTCOME MEASURES: Center of pressure displacements were recorded by using a force platform. RESULTS: Light finger touch resulted in decreased postural sway in the no-fatigue and fatigue conditions. Interestingly, this stabilizing effect was more accentuated in the fatigue condition. CONCLUSIONS: Results suggest that the contribution of the haptic cues from the finger for regulating postural sway increases after muscular fatigue. These findings could have implications in clinical and rehabilitative areas