Training improves oxidative capacity, but not function, in spinal muscular atrophy type III

Area of Science:

• Neurology
• Exercise Physiology
• Rehabilitation Science

Background:

• Spinal muscular atrophy type III (SMA III) is a progressive neuromuscular disorder characterized by muscle weakness and atrophy.
• Investigating the impact of structured exercise interventions is crucial for managing functional decline in SMA III patients.

Purpose of the Study:

• To evaluate the effects of a 12-week cycle ergometer training program on cardiorespiratory fitness and functional capacity in individuals with SMA III.
• To assess the safety and tolerability of this training regimen, particularly concerning fatigue.

Main Methods:

• Six SMA III patients and nine healthy controls underwent 12 weeks of supervised cycle ergometer training (42 sessions, 30 minutes each) at 65-70% of maximal oxygen uptake (VO2max).
• Assessments included VO2max, muscle strength, functional performance tests, and self-reported daily living activities, conducted pre- and post-intervention.

Main Results:

• Patients with SMA III demonstrated a significant 27% increase in VO2max (from 17±2 to 21±2 ml/kg/min, P < 0.001).
• Significant fatigue was reported, leading to one patient withdrawal, increased sleep needs in three, and training modifications in two patients.
• No evidence of muscle damage was observed.

Conclusions:

• Cycle exercise training can enhance cardiorespiratory fitness (VO2max) in SMA III patients without inducing muscle damage.
• The significant exercise-induced fatigue highlights the need for further research into alternative, potentially less strenuous, training modalities to improve exercise capacity in this population.