Effect of Exercise Training on Fitness in Multiple Sclerosis: A Meta-Analysis.

Objective: To provide a quantitative synthesis of randomized controlled trials (RCTs) examining the effect of exercise training on muscular and cardiorespiratory fitness in persons with multiple sclerosis (MS).

Data Sources: Three electronic databases, PubMed, Google Scholar, and Web of Science, were searched for all relevant articles published up until October 2014.

Study Selection: Keywords included exercise or aerobic or strength or resistance training or cardiorespiratory and multiple sclerosis. Trials examining the effect of exercise training on muscular and/or cardiorespiratory fitness parameters were included.

Data Extraction: The initial search yielded 1501 articles; of these, 62 were reviewed in detail, and 20 RCTs met the inclusion criteria and provided enough data to compute effect sizes (ESs) (Cohen d). The meta-analyses was conducted using a random effects model to compute the overall or mean ES per fitness parameter.

Data Synthesis: The mean ES was .27 (SE=.05; 95% confidence interval [CI], .17-.38; z=5.05; P<.001) for muscular fitness outcomes and .47 (SE=.09; 95% CI, .30-.65; z=5.4; P<.001) for cardiorespiratory fitness outcomes. The weighted mean ES was not heterogeneous for muscular (Q13=11.09, P=.60, I(2)=.00) or cardiorespiratory (Q9=7.83, P=.55, I(2)=.00) fitness outcomes.

Conclusions: The cumulative evidence supports that exercise training is associated with changes in muscular (small in magnitude) and cardiorespiratory (moderate in magnitude) fitness outcomes in persons with MS. Such an indication of magnitude is important for clinical research and practice by providing an evidence-based estimate of the actual benefit that exercise training confers on physiological fitness.