Muscle characteristics in ambulatory patients with Multiple Sclerosis and the effect of exercise training

Abstract

Objectives: Examining differences in fiber properties, oxidative capacity and capillarity, through comparing MyHC, SDH and CD31 stained samples between MS and healthy controls (HC). Correlations between clinical outcomes, subject characteristics and muscle characteristics were investigated. Furthermore, effects of a High Intensity Concurrent Training (HICT) intervention on these properties were examined in MS patients. Measurements: Primary outcome measures were fiber type distribution, fiber CSA, minimal Feret diameter, oxidative capacity, capillary density and capillary/fiber ratio. Furthermore, maximal oxygen uptake (VO2max) and the maximal cycling resistance (Wmax) were investigated during a maximal graded exercise test. Results: A significant difference in capillary density, VO2max and Wmax was found between HC and MS patients (p<0.05). Type I fibers had a significantly higher CSA, min. Feret diameter and fiber type distribution than type IIa and IIa+x fibers (p<0.05) in both MS patients and HC. No correlation between EDSS score and muscle properties was found. Secondly, VO2max and Wmax improved significantly (p<0.05) after the intervention. Conclusion: The capillary density, VO2max and Wmax seemed significantly affected by MS. No further effects were found. However, correlations between BMI - which is influenced by the disease - and muscle properties were observed. HICT improved VO2max and Wmax significantly, while no changes were observed in muscles.