Effect of training on skeletal muscle bioenergetic system in patients with mitochondrial myopathies: A computational study.

A computer model of the skeletal muscle bioenergetic system, involving the "Pi double-threshold" mechanism of muscle fatigue, was used to investigate the effect of muscle training on system kinetic properties in mitochondrial myopathies (MM) patients with inborn OXPHOS deficiencies. An increase in OXPHOS activity and decrease in peak Pi can account for the training-induced increase in V̇O2max, acceleration of the primary phase II of the V̇O2 on-kinetics, delay of muscle fatigue and prolongation of exercise at a given work intensity encountered in experimental studies. Depending on the mutation load and work intensity, training can bring the muscle from severe- to very-heavy- to moderate-exercise-like behavior, thus lessening the exertional fatigue and lengthening the physical activity of a given intensity. Training significantly increases critical power (CP) and slightly decreases the curvature constant (W') of the power-duration relationship. Generally, a mechanism underlying the training-induced changes in the skeletal muscle bioenergetic system in MM patients is proposed.

Self-management program improves participation in patients with neuromuscular disease: A randomized controlled trial.

OBJECTIVE: To investigate the effectiveness of Energetic, a self-management group program combining aerobic training, energy conservation management, and relapse prevention to improve social participation in patients with neuromuscular disease (NMD) and chronic fatigue. METHODS: In this multicenter, assessor-blinded, 2-armed randomized controlled trial with repeated measurements, 53 patients with various types of NMD and chronic fatigue were randomly allocated to Energetic, a 4-month group intervention, or to usual care. The primary endpoint was social participation assessed with the Canadian Occupational Performance Measure (COPM) performance scale immediately postintervention. Secondary outcomes included COPM satisfaction scale, 6-Minute Walk Test (6MWT), and Checklist Individual Strength-subscale fatigue. Participants were followed for 11 months postintervention. Data were analyzed with linear models that account for repeated measurements. RESULTS: Directly after intervention, the mean group difference for COPM-performance was 1.7 (95% confidence interval [CI] 1.0-2.4; p < 0.0001) in favor of the intervention group (n = 29), adjusted for baseline, sex, diagnosis, and work status. This effect was retained at 11 months follow-up (0.9; 95% CI 0.0-1.7; p = 0.049). The COPM satisfaction scale and 6MWT improved more in the intervention group compared to usual care. After 3 and 11 months follow-up, most beneficial effects on social participation and functional endurance were retained. CONCLUSION: Energetic led to sustainable improvements in social participation and functional endurance compared to usual care in patients with NMD and chronic fatigue.Clinicaltrials.gov IDENTIFIER: NCT02208687. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that a combination of aerobic training, energy conservation management, and relapse prevention improves social participation in patients with NMD and chronic fatigue.

Strength training and aerobic exercise training for muscle disease.

BACKGROUND: Strength training or aerobic exercise programmes might optimise muscle and cardiorespiratory function and prevent additional disuse atrophy and deconditioning in people with a muscle disease. This is an update of a review first published in 2004. OBJECTIVES: To examine the safety and efficacy of strength training and aerobic exercise training in people with a muscle disease. SEARCH METHODS: We searched the Cochrane Neuromuscular Disease Group Specialized Register (July 2012), CENTRAL (2012 Issue 3 of 4), MEDLINE (January 1946 to July 2012), EMBASE (January 1974 to July 2012), EMBASE Classic (1947 to 1973) and CINAHL (January 1982 to July 2012). SELECTION CRITERIA: Randomised or quasi-randomised controlled trials comparing strength training or aerobic exercise programmes, or both, to no training, and lasting at least six weeks, in people with a well-described diagnosis of a muscle disease.We did not use the reporting of specific outcomes as a study selection criterion. DATA COLLECTION AND ANALYSIS: Two authors independently assessed trial quality and extracted the data obtained from the full text-articles and from the original investigators. We collected adverse event data from included studies. MAIN RESULTS: We included five trials (170 participants). The first trial compared the effect of strength training versus no training in 36 people with myotonic dystrophy. The second trial compared aerobic exercise training versus no training in 14 people with polymyositis and dermatomyositis. The third trial compared strength training versus no training in a factorial trial that also compared albuterol with placebo, in 65 people with facioscapulohumeral muscular dystrophy (FSHD). The fourth trial compared combined strength training and aerobic exercise versus no training in 18 people with mitochondrial myopathy. The fifth trial compared combined strength training and aerobic exercise versus no training in 35 people with myotonic dystrophy type 1.In both myotonic dystrophy trials and the dermatomyositis and polymyositis trial there were no significant differences between training and non-training groups for primary and secondary outcome measures. The risk of bias of the strength training trial in myotonic dystrophy and the aerobic exercise trial in polymyositis and dermatomyositis was judged as uncertain, and for the combined strength training and aerobic exercise trial, the risk of bias was judged as adequate. In the FSHD trial, for which the risk of bias was judged as adequate, a +1.17 kg difference (95% confidence interval (CI) 0.18 to 2.16) in dynamic strength of elbow flexors in favour of the training group reached statistical significance. In the mitochondrial myopathy trial, there were no significant differences in dynamic strength measures between training and non-training groups. Exercise duration and distance cycled in a submaximal endurance test increased significantly in the training group compared to the control group. The differences in mean time and mean distance cycled till exhaustion between groups were 23.70 min (95% CI 2.63 to 44.77) and 9.70 km (95% CI 1.51 to 17.89), respectively. The risk of bias was judged as uncertain. In all trials, no adverse events were reported. AUTHORS' CONCLUSIONS: Moderate-intensity strength training in myotonic dystrophy and FSHD and aerobic exercise training in dermatomyositis and polymyositis and myotonic dystrophy type I appear to do no harm, but there is insufficient evidence to conclude that they offer 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.

Exercise in neuromuscular diseases.

This article reviews the current knowledge regarding the benefits and contraindications of exercise on individuals with neuromuscular diseases (NMDs). Specific exercise prescriptions for individuals with NMDs do not exist because the evidence base is limited. Understanding the effect of exercise on individuals with NMDs requires the implementation of a series of multicenter, randomized controlled trials that are sufficiently powered and use reliable and valid outcome measures to assess the effect of exercise interventions-a major effort for each NMD. In addition to traditional measures of exercise efficacy, outcome variables should include measures of functional status and health-related quality of life.

Strength training and aerobic exercise training for muscle disease.

BACKGROUND: Strength training or aerobic exercise programmes might optimise muscle and cardiorespiratory function and prevent additional disuse atrophy and deconditioning in people with a muscle disease. OBJECTIVES: To examine the safety and efficacy of strength training and aerobic exercise training in people with a muscle disease. SEARCH STRATEGY: We searched the Cochrane Neuromuscular Disease Group Trials Specialized Register (July 2009), the Cochrane Rehabilitation and Related Therapies Field Register (October 2002, August 2008 and July 2009), The Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, 2009) MEDLINE (January 1966 to July 2009), EMBASE (January 1974 to July 2009), EMBASE Classic (1947 to 1973) and CINAHL (January 1982 to July 2009). SELECTION CRITERIA: Randomised or quasi-randomised controlled trials comparing strength training or aerobic exercise programmes, or both, to no training, and lasting at least 10 weeks.For strength training Primary outcome: static or dynamic muscle strength. Secondary: muscle endurance or muscle fatigue, functional assessments, quality of life, muscle membrane permeability, pain and experienced fatigue.For aerobic exercise training Primary outcome: aerobic capacity expressed as work capacity. Secondary: aerobic capacity (oxygen consumption, parameters of cardiac or respiratory function), functional assessments, quality of life, muscle membrane permeability, pain and experienced fatigue. DATA COLLECTION AND ANALYSIS: Two authors independently assessed trial quality and extracted the data. MAIN RESULTS: We included three trials (121 participants). The first compared the effect of strength training versus no training in 36 people with myotonic dystrophy. The second trial compared strength training versus no training, both combined with albuterol or placebo, in 65 people with facioscapulohumeral muscular dystrophy. The third trial compared combined strength training and aerobic exercise versus no training in 18 people with mitochondrial myopathy. In the myotonic dystrophy trial there were no significant differences between training and non-training groups for primary and secondary outcome measures. In the facioscapulohumeral muscular dystrophy trial only a +1.17 kg difference (95% confidence interval 0.18 to 2.16) in dynamic strength of elbow flexors in favour of the training group reached statistical significance. In the mitochondrial myopathy trial there were no significant differences in dynamic strength measures between training and non-training groups. Exercise duration and distance cycled in a submaximal endurance test increased significantly in the training group compared to the control group. AUTHORS' CONCLUSIONS: 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.

Short- and long-term effects of endurance training in patients with mitochondrial myopathy.

BACKGROUND AND PURPOSE: It is unknown whether prolonged training is a safe treatment to alleviate exercise intolerance in patients with mitochondrial DNA (mtDNA) mutations. METHODS: The effect of 3 and 12 months training and 3-12 months deconditioning was studied in four patients carrying different mtDNA mutations. RESULTS: Three-month moderate-intensity training increased oxidative capacity by 23%, which was sustained after 6-12 months of low-intensity training. Training and deconditioning did not induce adverse effects on clinical symptoms, muscle morphology and mtDNA mutation load in muscle. CONCLUSION: Long-term training effectively improves exercise capacity in patients with mitochondrial myopathy, and appears to be safe.

Facilitação neuromuscular proprioceptiva (FNP) na miopatia mitocondrial: estudo de caso / Proprioceptive neuromuscular facilitation (PNF) on mitochondrial myopathy: case study

Introdução: As miopatias mitocondriais são consideradas um grupo de desordens que podem comprometer uma variedade de órgãos e apresentar fenótipos variáveis. Frequentemente afetam o sistema nervoso central e a musculatura esquelética e cardíaca. Objetivo: Investigar os efeitos de um programa individualizado, baseado nas técnicas de facilitação neuromuscular proprioceptiva (FNP), no gerenciamento da fraqueza muscular e habilidades funcionais de um paciente com miopatia mitocondrial de início tardio e distribuição atípica. Material e métodos: O paciente foi submetido a uma avaliação da força muscular e da capacidade funcional antes e após 12 semanas de tratamento, composto por exercícios de intensidade leve/moderada, com duração de 60 minutos/sessão e frequência de 2 atendimentos semanais. Resultados e Discussão: Ganhos relacionados à força muscular foram obtidos em determinados grupamentos musculares. O nível de independência funcional não sofreu alterações após a proposta terapêutica, entretanto manteve-se estabilizado. Conclusão: O programa reabilitativo atuou na minimização das complicações geradas pela fraqueza muscular e na otimização das atividades quotidianas. A reabilitação física faz-se necessária para um melhor gerenciamento da fraqueza muscular e da habilidade do paciente na execução de atividades básicas e instrumentais da vida diária.

Resistance training in patients with single, large-scale deletions of mitochondrial DNA.

Dramatic tissue variation in mitochondrial heteroplasmy has been found to exist in patients with sporadic mitochondrial DNA (mtDNA) mutations. Despite high abundance in mature skeletal muscle, levels of the causative mutation are low or undetectable in satellite cells. The activation of these typically quiescent mitotic cells and subsequent shifting of wild-type mtDNA templates to mature muscle have been proposed as a means of restoring a more normal mitochondrial genotype and function in these patients. Because resistance exercise is known to serve as a stimulus for satellite cell induction within active skeletal muscle, this study sought to assess the therapeutic potential of resistance training in eight patients with single, large-scale mtDNA deletions by assessing: physiological determinants of peak muscle strength and oxidative capacity and muscle biopsy-derived measures of damage, mtDNA mutation load, level of oxidative impairment and satellite cell numbers. Our results show that 12 weeks of progressive overload leg resistance training led to: (i) increased muscle strength; (ii) myofibre damage and regeneration; (iii) increased proportion of neural cell adhesion molecule (NCAM)-positive satellite cells; (iv) improved muscle oxidative capacity. Taken together, we believe these findings support the hypothesis of resistance exercise-induced mitochondrial gene-shifting in muscle containing satellite cells which have low or absent levels of deleted mtDNA. Further investigation is warranted to refine parameters of the exercise training protocol in order to maximize the training effect on mitochondrial genotype and treatment potential for patients with selected, sporadic mutations of mtDNA in skeletal muscle.

Effects of aerobic training in patients with mitochondrial myopathies.

We studied the physiologic adaptation of patients with mitochondrial myopathies to aerobic training. Ten patients underwent individually supervised, moderate-intensity aerobic training on a treadmill for 8 weeks. Biochemical and functional measures improved with training. Estimated aerobic capacity increased by 30%. Blood lactate concentrations at rest and after exercise decreased by 30%. Muscle phosphorus magnetic resonance spectroscopy measurements of adenosine diphosphate recovery after exercise improved by more than 60%. Fatigue and tolerance to daily activities also improved. Although the improvement in exercise tolerance may be due in part to reversal of the effects of secondary deconditioning, this uncontrolled clinical trial suggests that aerobic training can benefit patients with mitochondrial myopathies.