High Intensity Exercise in Multiple Sclerosis: Effects on Muscle Contractile Characteristics and Exercise Capacity, a Randomised Controlled Trial

Abstract

Introduction: Low-to-moderate intensity exercise improves muscle contractile properties and endurance capacity in multiple sclerosis (MS). The impact of high intensity exercise remains unknown.

Methods: Thirty-four MS patients were randomized into a sedentary control group (SED, n = 11) and 2 exercise groups that performed 12 weeks of a high intensity interval (HITR, n = 12) or high intensity continuous cardiovascular training (HCTR, n = 11), both in combination with resistance training. M.vastus lateralis fiber cross sectional area (CSA) and proportion, knee-flexor/extensor strength, body composition, maximal endurance capacity and self-reported physical activity levels were assessed before and after 12 weeks.

Results: Compared to SED, 12 weeks of high intensity exercise increased mean fiber CSA (HITR: +21 ± 7%, HCTR: +23 ± 5%). Furthermore, fiber type I CSA increased in HCTR (+29 ± 6%), whereas type II (+23 ± 7%) and IIa (+23 ± 6%,) CSA increased in HITR. Muscle strength improved in HITR and HCTR (between +13 ± 7% and +45 ± 20%) and body fat percentage tended to decrease (HITR: -3.9 ± 2.0% and HCTR: -2.5 ± 1.2%). Furthermore, endurance capacity (Wmax +21 ± 4%, time to exhaustion +24 ± 5%, VO2max +17 ± 5%) and lean tissue mass (+1.4 ± 0.5%) only increased in HITR. Finally self-reported physical activity levels increased 73 ± 19% and 86 ± 27% in HCTR and HITR, respectively.

Conclusion: High intensity cardiovascular exercise combined with resistance training was safe, well tolerated and improved muscle contractile characteristics and endurance capacity in MS.

Trial registration: ClinicalTrials.gov NCT01845896.

Conflict of interest statement

Competing Interests: Inez Wens received support from MS Fund Limburg, Flanders, to perform this research. Ulrik Dalgas has received research support, travel grants and/or teaching honorary from Biogen Idec, Merck Serono and Sanofi Aventis and further serves as PI for the ongoing Biogen sponsored ACTIMS study. Frank Vandenabeele, Maartje Krekels, Lotte Grevendonk, Kenneth Verboven and Dominique Hansen report no disclosure. Bert Op ’t Eijnde received support from MS Fund Limburg, Flanders, to perform this research. This does not alter our adherence to Plos One policies on sharing data and materials.

Figures

Fig 1. Consort flow diagram for participants’ inclusion.

Fig 2. Representative image of fiber type analysis before (left) and after (right) high intensity exercise.

Different fiber types are distinguished by color (dark blue: type I, pink: type IIa, green: type IIx, light blue: type IIc). Calculation of the fiber CSA was performed for the major fiber types (I, IIa and IIx) and for the mean fiber CSA, since the number of fibers expressing the minor fiber types (IIax and IIc) was too small for statistical comparison and CSA calculation.

Fig 3. Percentage change of knee extension and flexion after 12 weeks of physical inactive living (usual care, SED), high intensity continuous training + resistance training (HCTR) and high intensity interval training + resistance training (HITR).

Data are reported as mean ± SE. * p