Variation of muscle power after twelve weeks of resistance training in multiple sclerosis patients

C. Medina-Pérez, F. de Souza-Teixeira, R. Fernandez-Gonzalo, J.A. de Paz-Fernández (Leon, ES; Pelotas, BR; Stockholm, SE)

Objective: This study was designed to evaluate the variation in leg muscle power after resistance training program of 12-wk and a detraining period of the same duration in multiple sclerosis (MS) patients.

Methods: Forty-two relapsing-remitting MS patients (23 women and 19 men; age range 32-70 yr) volunteered to participate in this study. A neurological evaluation assessing the Expanded Disability Status Scale (EDSS; from 0, normal neurological exam, to 10, death caused by MS) ranged the patients between 1 and 6 (mean ± SD: 4.3 ± 1.3). They followed a resistance training program (2 sessions/week; incremental loads: 35-70% of maximal isometric strength); and a control group (n = 12), who continued their habitual activities. Muscle power was evaluated before and after the 12-wk training program and after 12 weeks of detraining. Participants were evaluated during a single set of coupled CON/ECC repetitions in seated knee extension machine to volitional exhaustion with a load corresponding to the 40% of pre-training maximal isometric voluntary contraction. A linear encoder (Globus Real Power®, Italy; sample rate 300 Hz) adapted to the machine was used to record the displacement of the load-plates across the knee’s range of movement (90° to 180°), and associated software (Globus Real Power® v3.11, Italy) was used to calculate average power for every repetition. Average power from the first five repetitions was considered for further data analysis.

Results: Exercise group increased muscle power after the training period (Baseline: 173.3±72.0 W; Week-12: 200.2±80.5 W). However, muscle power was not affected by the detraining period (Week-24: 193.3±78.3 W). Control group did not present important changes in muscle power during the intervention (Baseline: 149.5±34.1 W; Week-12: 148.1±29.4 W; Week-24: 154.7±43.0 W).

Conclusion: A 12-wk resistance training program improved muscle power in MS patients and muscle power training adaptations were maintained after detraining period.