title: 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.
authors.affiliation: Department of Health and Exercise Science, University of Oklahoma, Norman, OK 73019, USA. rdlarson@ou.edu
authors.forename: Rebecca D
authors.initials: RD
authors.lastname: Larson
authors.forename: Kevin K
authors.initials: KK
authors.lastname: McCully
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Larson
authors.forename: William M
authors.initials: WM
authors.lastname: Pryor
authors.forename: Lesley J
authors.initials: LJ
authors.lastname: White
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology; D016022:Case-Control Studies; D005080:Exercise Test; D005260:Female; D006801:Humans; D035002:Lower Extremity / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000503:physiopathology*; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000503:physiopathology*; D010101:Oxygen Consumption; D005082:Physical Exertion