Six minutes of walking leads to reduced lower limb strength and increased postural sway in people with Multiple Sclerosis

BACKGROUND: Fatigue, lower limb weakness and poor balance can significantly limit safe mobility in people with Multiple Sclerosis (MS). Further research is required to elucidate relationships among these factors.

OBJECTIVE: To investigate the effect of walking-induced fatigue on lower limb strength and postural sway in people with moderately disabling MS.

METHODS: Thirty-four people (26 female) with moderate MS (mean Expanded Disability Status Scale of 3.7 ± 0.7) underwent assessments of acute fatigue, postural sway and lower limb strength before and after six-minute conditions of seated rest and walking. A matched sample of 10 healthy controls also undertook identical assessments before and after a six-minute walk. RESULTS: Significant time by condition effects for all assessment measures indicated the six-minute walk induced fatigue with associated increases in postural sway and reductions in lower limb strength in people with MS. Increases in sway with eyes closed correlated with increases in acute fatigue and self-reported impact of fatigue on physical and psychological functioning. No changes were observed in healthy controls. CONCLUSION: People with MS show signs of fatigue after 6 minutes of walking, including strength and balance deficits. These findings have implications for both mobility and fall risk in this group.