Training for Muscle Diseases

A Cochrane review [Abstract] 1 included 14 RCTs with a total of 428 subjects. An exercise duration was from 8 to 52 weeks, the patients had facioscapulohumeral muscular dystrophy (FSHD), dermatomyositis, polymyositis, mitochondrial myopathy, Duchenne muscular dystrophy (DMD), or myotonic dystrophy. None of the training schemes used in the strength training studies were adequate with respect to the number of muscle groups trained.

• Strength training vs. no training (3 trials): For patients with FSHD (n=35), there was little or no effect on dynamic strength of elbow flexors (MD 1.2 kgF, 95% CI −0.2 to 2.6), on isometric strength of elbow flexors (MD 0.5 kgF, 95% CI −0.7 to 1.8), and ankle dorsiflexors (MD 0.4 kgF, 95% CI −2.4 to 3.2), and on dynamic strength of ankle dorsiflexors (MD −0.4 kgF, 95% CI −2.3 to 1.4). For patients with myotonic dystrophy type 1 (n=35), there was a slight improvement in isometric wrist extensor strength (MD 8.0 N, 95% CI 0.7 to 15.3) but little or no effect on hand grip force (MD 6.0 N, 95% CI −6.7 to 18.7), pinch grip force (MD 1.0 N, 95% CI −3.3 to 5.3) and isometric wrist flexor force (MD 7.0 N, 95% CI −3.4 to 17.4).
• Aerobic exercise training vs. no training (5 trials): For patients with DMD the was uncertain regarding the number of leg revolutions (MD 14.0, 95% CI −89.0 to 117.0; n=23) or arm revolutions (MD 34.8, 95% CI −68.2 to 137.8; n=23) during an assisted 6-minute cycle test, and regarding muscle strength (MD 1.7, 95% CI −1.9 to 5.3; n=15). For patients with FSHD, there was improvement in aerobic capacity (MD 1.1 L/min, 95% CI 0.4 to 1.8; n=38) but little or no effect on knee extension strength (MD 0.1 kg, 95% CI −0.7 to 0.9; n=52). For patients with dermatomyositis and polymyositis (n=14), there was effect on aerobic capacity was uncertain (MD 14.6, 95% CI −1.0 to 30.2).
• Combined aerobic exercise and strength training vs. no training (6 trials): For patients with juvenile dermatomyositis (n=26) there was improvement in knee extensor strength on the right (MD 36.0 N, 95% CI 25.0 to 47.1) and left (MD 17 N 95% CI 0.5 to 33.5), but little or no effect on maximum force of hip flexors on the right (MD −9.0 N, 95% CI −22.4 to 4.4) or left (MD 6.0 N, 95% CI −6.6 to 18.6). This trial also showed slight decrease of aerobic capacity (MD −1.2 min, 95% CI −1.6 to 0.9). For patients with dermatomyositis and polymyositis (n=21), there was slight increases in muscle strength as measured by dynamic strength of knee extensors on the right (MD 2.5 kg, 95% CI 1.8 to 3.3) and on the left (MD 2.7 kg, 95% CI 2.0 to 3.4) and no clear effect in isometric muscle strength of 8 different muscles (MD 1.0, 95% CI −1.1 to 3.1). There was an increase in aerobic capacity, as measured with time to exhaustion in an incremental cycle test (17.5 min, 95% CI 8.0 to 27.0) and power performed at VO2 max (maximal oxygen uptake) (18 W, 95% CI 15.0 to 21.0). For patients with mitochondrial myopathy (n=18), the effect was uncertain regarding shoulder muscle (MD −5.0 kg, 95% CI −14.7 to 4.7), pectoralis major muscle (MD 6.4 kg, 95% CI −2.9 to 15.7), and anterior arm muscle strength (MD 7.3 kg, 95% CI −2.9 to 17.5). There was some effect regarding aerobic capacity, as measured with mean time cycled (MD 23.7 min, 95% CI 2.6 to 44.8) and mean distance cycled until exhaustion (MD 9.7 km, 95% CI 1.5 to 17.9).

Most trials reported no adverse events other than muscle soreness or joint complaints.

Comment: The quality of evidence is downgraded by inconsistency (heterogeneity in interventions), imprecise results (few patients and wide confidence intervals) and indirectness (differences in interventions).

References

• Voet NB, van der Kooi EL, van Engelen BG et al. Strength training and aerobic exercise training for muscle disease. Cochrane Database Syst Rev 2019;12():CD003907.[PubMed]