Resistance Training for Muscle Weakness in Multiple Sclerosis: Direct Versus Contralateral Approach in Individuals With Ankle Dorsiflexors' Disparity in Strength

Abstract Objective To compare effects of contralateral strength training (CST) and direct strength training of the more affected ankle dorsiflexors on muscle performance and clinical functional outcomes in people with multiple sclerosis (MS) exhibiting interlimb strength asymmetry. Design Randomized controlled trial. Setting University hospital. Participants Individuals with relapsing-remitting MS (N=30) and mild-to-moderate disability (Expanded Disability Status Scale score ≤6) presenting with ankle dorsiflexors' strength disparity. Interventions Participants were randomly assigned to a CST (n=15) or direct strength training (n=15) group performing 6 weeks of maximal intensity strength training of the less or more affected dorsiflexors, respectively. Main Outcome Measures Maximal strength, endurance to fatigue, and mobility outcomes were assessed before, at the intervention end, and at 12-week follow-up. Strength and fatigue parameters were measured after 3 weeks of training (midintervention). Results In the more affected limb of both groups, pre- to postintervention significant increases in maximal strength ( P ≤.006) and fatigue endurance ( P ≤.04) were detected along with consistent retention of these improvements at follow-up ( P ≤.04). At midintervention, the direct strength training group showed significant improvements ( P ≤.002), with no further increase at postintervention, despite training continuation. Conversely, the CST group showed nonsignificant strength gains, increasing to significance at postintervention ( P ≤.003). In both groups, significant pre- to postintervention improvements in mobility outcomes ( P ≤.03), not retained at follow-up, were observed. Conclusions After 6 weeks of training, CST proved as effective as direct strength training in enhancing performance of the more affected limb with a different time course, which may have practical implications in management of severely weakened limbs where direct strength training is not initially possible.