Strength training in patients with myotonic dystrophy and hereditary motor and sensory neuropathy: a randomized clinical trial. Effects of training and albuterol on pain and fatigue in facioscapulohumeral muscular dystrophy.
A randomized clinical trial on the effects of strength training was performed in myotonic dystrophy (MyD) patients and patients with hereditary motor and sensory neuropathy (HMSN). Training and most measurement tools involved the proximal lower extremity muscles. The participants trained 3 times a week for 24 weeks with weights adapted to their force. Strength was evaluated by isokinetically measured knee torque. Fatiguability was assessed by the time an isometric contraction could be sustained. Functional performance was measured by timed motor performance and by questionnaires on functional performance. Serum myoglobin (Mb) levels were determined to detect changes in muscle fiber membrane permeability. The MyD group included 33 participants, and the HMSN group included 29 participants. Within each diagnostic group, patients were individually matched and subsequently randomized for treatment allocation. In the MyD patients, none of the measurement techniques showed any training effect. Neither were there signs of deterioration caused by the training. In the HMSN group, knee torques increased. Timed motor performance did not change, although the questionnaires showed an improvement on items related to upper-leg function. Mb levels did not change significantly as a result of the training. In conclusion, the MyD group showed neither positive nor negative effects of the training protocol, whereas the training produced a moderate increase in strength and leg-related functional performance in the HMSN group. We recently reported a randomised controlled trial on the efficacy of strength training and the beta2-adrenergic agonist albuterol in patients with facioscapulohumeral muscular dystrophy (FSHD). Strength training and albuterol appeared safe interventions with limited positive effect on muscle strength and volume. We concurrently explored the prevalence and the characteristics of pain and fatigue in the participating FSHD patients, because these are probably underreported but clinically relevant symptoms in this disorder. Next, we studied the effects of albuterol and strength training on pain, experienced fatigue, health-related functional status and psychological distress.
                Sixty-five patients were randomised to strength training of elbow flexors and ankle dorsiflexors or non-training. After 26 weeks, albuterol (sustained-release, 8 mg bid) was added in a randomised, double-blind, placebo-controlled design. Outcomes comprised self-reported pain, experienced fatigue, functional status and psychological distress obtained with validated questionnaires at 52 weeks.
                Eighty percent of patients reported chronic persistent or periodic, multifocal pains. Thirty-four percent of the participants were severely fatigued. Strength training and albuterol failed to have a significant effect on all outcomes.
                Pain and fatigue are important features in FSHD. Strength training and albuterol do not have a positive or negative effect on pain, experienced fatigue, functional status and psychological distress.
In myotonic dystrophy and facioscapulohumeral muscular dystrophy, moderate-intensity strength training appears not to do harm but there is insufficient evidence to conclude that it offers benefit. In mitochondrial myopathy, aerobic exercise combined with strength training appears to be safe and may be effective in increasing submaximal endurance capacity. Limitations in the design of studies in other muscle diseases prevent more general conclusions in these disorders.