High-intensity training in patients with spinal and bulbar muscular atrophy.

Long duration, moderate-intensity exercise is not well tolerated in patients with spinal and bulbar muscular atrophy (SBMA). This study investigated whether patients with SBMA can benefit from high-intensity training (HIT).

Ten patients with SBMA were randomized to 8 weeks of supervised HIT [n = 5; age = 50 (25-63) years] followed by 8 weeks of self-training or 8 weeks of no training followed by 8 weeks of non-supervised HIT [n = 5; age = 50 (26-54) years]. Training consisted of 2 × 5-min exercise periods with 1-min cyclic blocks of intermittent maximal intensity exercise on an ergometer bike. Maximal oxygen capacity (VO_2max) and workload (W_max) were measured before and after training by incremental exercise tests. Plasma creatine kinase levels, self-rated muscle pain, muscle fatigue, and activity level were monitored throughout the training period.

Eight patients completed training. One patient dropped out after 5 weeks of training for private reasons. Another patient was excluded after 4 weeks due to lack of compliance. Eight weeks of training increased both VO_2max (1.9 ± 2.3 ml min^-1 kg^-1; p = 0.04) and W_max (15.6 ± 17.9 W; p = 0.03) in the 8 patients who completed training. There were no changes in plasma creatine kinase levels, self-reported muscle pain or muscle fatigue activity level after training.

This pilot study suggests that high-intensity training is safe and improves fitness in patients with SBMA. Unlike low- and moderate-intensity training, HIT is efficacious and favored over other training forms by the patients.