L Berger1, S-C Regueme, N Forestier. 1. Laboratoire de physiologie de l'exercice, domaine universitaire du Bourget du Lac, université de Savoie, 73376 Le-Bourget-du-Lac cedex, France. laetitia.berger@univ-savoie.fr
Abstract
OBJECTIVE: Fatigue of lower limb presents various impacts on postural control. The purpose of this study was to explore the effects of a unilateral lower-limb muscle fatigue on undisturbed stance. METHODS: Nine healthy men performed until exhaustion a fatiguing exercise of the limb extensor muscles of one leg (exercised leg). Just before and after the fatiguing exercise, postural sway measures (centre of pressure) were recorded simultaneously from a double force platform and an in-shoe pressure system in quiet standing conditions. Maximal plantar pressure was computed from each sensor of the in-shoe system, before being averaged for the medial and lateral heel, the external mid-foot, the external and internal foreparts. RESULTS: In undisturbed stance, the fatiguing exercise induced postural destabilisation for the non-exercised leg (P < 0.001). Changes in antero-posterior mean position of the exercised leg were also observed reflecting a mean loading in a more rear foot stance (P < 0.01). The in-shoe system parameters revealed for the exercised foot, an increase of the maximal pressure value for the heel region (P < 0.05) and a decrease for the mid-foot and forepart (P < 0.05). For the non-exercised foot, the maximal pressure decreased only in forepart (P < 0.05). CONCLUSIONS: Unilateral triceps surae fatigue revealed an immediate destabilisation of undisturbed stance and the observed postural strategy appears similar to these developed by patients who presented pain pathology and/or sensory deficits in lower limb.
OBJECTIVE: Fatigue of lower limb presents various impacts on postural control. The purpose of this study was to explore the effects of a unilateral lower-limb muscle fatigue on undisturbed stance. METHODS: Nine healthy men performed until exhaustion a fatiguing exercise of the limb extensor muscles of one leg (exercised leg). Just before and after the fatiguing exercise, postural sway measures (centre of pressure) were recorded simultaneously from a double force platform and an in-shoe pressure system in quiet standing conditions. Maximal plantar pressure was computed from each sensor of the in-shoe system, before being averaged for the medial and lateral heel, the external mid-foot, the external and internal foreparts. RESULTS: In undisturbed stance, the fatiguing exercise induced postural destabilisation for the non-exercised leg (P < 0.001). Changes in antero-posterior mean position of the exercised leg were also observed reflecting a mean loading in a more rear foot stance (P < 0.01). The in-shoe system parameters revealed for the exercised foot, an increase of the maximal pressure value for the heel region (P < 0.05) and a decrease for the mid-foot and forepart (P < 0.05). For the non-exercised foot, the maximal pressure decreased only in forepart (P < 0.05). CONCLUSIONS: Unilateral triceps surae fatigue revealed an immediate destabilisation of undisturbed stance and the observed postural strategy appears similar to these developed by patients who presented pain pathology and/or sensory deficits in lower limb.