Bilateral differences in lower-limb performance in individuals with multiple sclerosis

Abstract

Bilateral differences in lower-limb strength in people with multiple sclerosis (MS) have been clinically observed. The objectives of this study were to quantify bilateral differences in lower-limb performance and metabolism during exercise. Eight ambulatory individuals with mild MS with an Expanded Disability Status Scale score of 2.6 +/- 1.6 and seven non-MS controls completed bilateral assessments of muscle strength and incremental cycling. Individuals with MS had significant (p < 0.05) between-leg differences in leg strength (strong leg: 43.3 +/- 12.7 kg vs weak leg: 37.7 +/- 15.2 kg), peak oxygen uptake (strong leg: 13.7 +/- 3.2 mL/kg/min vs weak leg: 10.6 +/- 3.0 mL/kg/min), and peak workload (strong leg: 73.4 +/- 22.3 W vs weak leg: 56.3 +/- 26.2 W). No between-leg differences were found in controls (p > 0.05). As anticipated, individuals with MS exhibited significantly greater asymmetry for strength, oxygen uptake, and workload than controls (p < 0.05). The differences between legs varied from 2% to 30% for maximal strength and 4% to 66% for cycling workload in the MS group and 4% to 24% and 0% to 8% for the control group, respectively. Preliminary evidence suggests that the magnitude of differences may be related to limitations in aerobic function.

Glucose uptake heterogeneity of the leg muscles is similar between patients with multiple sclerosis and healthy controls during walking

“…Muscle weakness is common in patients with MS, but is not always present and can vary by muscle group [22, 28, 29, 30]. Asymmetries in muscular strength have also been found, which were associated with motor task deficits [2, 13, 28, 29]. The causes for these asymmetries are not well understood at this time.…”

Lower-limb performance disparities: Implications for exercise prescription in multiple sclerosis

“…This investigation was part of a larger study that involved physical performance testing [5]. All participants had a defined stronger leg and weaker leg based on leg extensor strength assessments.…”

“…In a 2011 study, Larson and White observed bilateral differences in hip bone density in ambulatory individuals with MS, which may illustrate consequences of altered bilateral function [8]. Additionally, Larson et al in 2013 observed that individuals with MS exhibited significant leg asymmetry in strength, oxidative capacity, and work performed, suggesting that the magnitude of bilateral differences might limit functional abilities [5].…”

“…Evidence suggests that individuals with MS exhibit bilateral differences in strength and function [3][4][5], which may help explain, in part, higher energy demand during exercise that could contribute to early onset muscle fatigue and reduced exercise tolerance. A 2005 case study by White and Dressendorfer reported bilateral differences in leg strength and maximal oxygen uptake in an individual with MS who exhibited left leg exercise-induced monoparesis [4].…”

Core muscle characteristics during walking of patients with multiple sclerosis

“…Larson et al used incremental unilateral cycling to demonstrate asymmetric peak workload and strength between legs in patients with MS [36]. Participants cycled under a ramped protocol until volitional exhaustion.…”