The Effect of Aerobic Exercise Training on Patients with Type III Spinal Muscular Atrophy

Background: Spinal muscular atrophy (SMA) is a neurodegenerative disorder caused by variants in the SMN1 gene. This study investigates the functional and biochemical effects of moderate-intensity aerobic exercise in SMA Type III patients. Methods: Twenty-three patients aged 18-57 years were included in this study. The training group underwent a 12-week aerobic exercise program using a bicycle ergometer at 60-70% of their maximum heart rate three times per week for 30 min per session. The training continued for an additional four months. The primary outcome measures were the six-minute walk distance and oxygen uptake, both reflecting exercise capacity. Secondary outcome measures included muscle strength with dynamometer, functional performance, and fatigue with different scales. Furthermore, serum survival motor neuron (SMN) protein and insulin-like growth factor-1 (IGF-1) hormone levels were measured at baseline, post-training first measurement (after 12 weeks), and post-training second measurement (after 28 weeks). Results: The exercise group showed a significant increase in exercise capacity (p < 0.001) and 6MWT walking distance (p = 0.003). Furthermore, reduction in walking time in the 10-m walk test (p = 0.019) and improvements in strength of the right and left quadriceps (p = 0.004, p = 0.031) and right gastrocnemius (p = 0.034) muscles were identified. Furthermore, an improvement in the Fatigue Severity Scale (FSS) (p = 0.037) was found. SMN protein and IGF-1 levels were increased in the second measurement in the training group (p = 0.022 and p = 0.016, respectively). Conclusions: An aerobic exercise program improved physical function and muscle strength and reduced fatigue in SMA Type III patients, with sustained biochemical improvements. Aerobic exercise may serve as a beneficial adjunct therapy for this population.