Response to high-intensity eccentric muscle contractions in persons with myopathic disease

Exercise Training as Part of Musculoskeletal Management for Congenital Myopathy: Where Are We Now?

Congenital myopathy is a heterogeneous group of muscle disorders characterized by muscle weakness and hypotonia. This condition is associated with a range of skeletal, respiratory, and ophthalmologic complications and requires a multidisciplinary therapeutic approach aimed at maximizing the function and independence of patients. One promising direction for therapeutic intervention is physical exercise rehabilitation, given its demonstrated ability to promote muscle and bone health of patients with a variety of neuromuscular conditions. However, there are few data to assist health care professionals identify the optimal physical activity levels and exercise type, including the intensity, frequency, and duration. This lack of empirical evidence is particularly problematic given the fact that inappropriate exercise modes can potentially cause muscle damage in patients with congenital myopathy. In this article, we discuss the rationale behind the incorporation of two types of physical exercises, strength and aerobic training, into the clinical care of patients with congenital myopathy. Given the paucity of literature on the management of congenital myopathy, we review the results of published research on the treatment of both congenital myopathy and other neuromuscular diseases that could provide helpful insights into the physical rehabilitation of patients with congenital myopathy. We also discuss the potential benefits of vibration therapy, which has been studied in patients with other neuromuscular disorders over the last two decades. We conclude by proposing directions for future research on physical rehabilitation of patients with congenital myopathy.

Minimal Evidence for a Secondary Loss of Strength After an Acute Muscle Injury: A Systematic Review and Meta-Analysis

BACKGROUND

An immediate loss of strength follows virtually all types of muscle injury but there is debate whether the initial strength loss is maximal or if a secondary loss of strength occurs during the first 3 days post-injury.

OBJECTIVE

The objective of this analysis was to conduct a systematic review and meta-analysis of the research literature to determine if a secondary loss of strength occurs after an injurious initiating event.

METHODS

Literature searches were performed using eight electronic databases (e.g., PubMed, Cochrane Library). Search terms included skeletal muscle AND (injur* OR damage*) AND (strength OR force OR torque). The extracted strength data were converted to a standard format by calculating the standardized mean difference, which is reported as the effect size (ES) along with its 95 % confidence interval (CI). The calculation of ES was designed so that a negative ES that was statistically less than zero would be interpreted as indicating a secondary loss of strength.

RESULTS

A total of 223 studies with over 4000 human and animal subjects yielded data on 262 independent groups and a total of 936 separate ESs. Our overall meta-analysis yielded a small-to-medium, positive overall ES that was statistically greater than zero (overall ES = +0.34, 95 % CI 0.27-0.40; P < 0.00000001). Considerable variation in ES was observed among studies (I ² = 86 %), which could be partially explained by the research group conducting the study, sex of the subject, day of post-injury strength assessment, whether fatigue was present immediately post-injury, and the muscle group injured. From the subgroup meta-analyses probing these variables, 36 subgroup ESs were calculated and none were statistically less than zero.

CONCLUSION

Overall, our findings do not support the presence of a secondary loss of strength following an acute muscle injury, and strongly suggest that strength, on average, recovers steadily over the first 3 days post-injury.

Deviation in the recovery of the lower limb and respiratory muscles of patients with polymyositis: a preliminary clinical study

[Purpose] The purposes of this study were to quantify the serial changes in lower limb and respiratory muscle strengths and to evaluate the acute effects of physiotherapy in polymyositis patients. [Subjects and Methods] Five patients (57.6 ± 9.0 years, 50 to 72; four females) received physiotherapy five days a week for four weeks. The lower limb and respiratory muscle strength, the % vital capacity, and the Barthel index were evaluated at baseline and after the intervention. [Results] The patient’s symptoms and creatine kinase values did not change, and after four weeks, all of the patients exhibited significantly increased outcomes compared with the baseline. However, the inspiratory muscle strength of the patients presented smaller improvements than the expiratory muscle strength. [Conclusion] Differential changes in inspiratory and expiratory muscle strength were observed following physiotherapy, and an unbalanced muscle distribution may explain the pathological and therapeutic effects.

Facioscapulohumeral distrophy and physiotherapy: a literary review

[Purpose] The purpose of this review was to critically evaluate the literature concerning the physiotherapy of facioscapulohumeral dystrophy, and to determine an effective protocol for physiotherapy treatments, which can be adapted to patient characteristics. [Methods] A bibliographic research was carried out of research papers held in the following databases: PUBMED, PEDRO, MEDLINE, EDS BASE INDEX. The inclusion criteria for acceptance of the studies to the review were randomized controlled trials (RCTs) concerning a sample no smaller than 10 people and a medium- or long-term report of the results achieved. [Results] Just six of the works satisfied the inclusion criteria, and just three of them were useful for the review. However, these studies were difficult to compare. [Conclusion] At present, there are few studies concerning facioscapulohumeral dystrophy in the literature, and the few that are available rule out the utility of the techniques used. Therefore, more RCTs of new treatment strategies are needed.

Efficacy of muscle exercise in patients with muscular dystrophy: a systematic review showing a missed opportunity to improve outcomes

BACKGROUND

Although muscular dystrophy causes muscle weakness and muscle loss, the role of exercise in the management of this disease remains controversial.

OBJECTIVE

The purpose of this systematic review is to evaluate the role of exercise interventions on muscle strength in patients with muscular dystrophy.

METHODS

We performed systematic electronic searches in Medline, Embase, Web of Science, Scopus and Pedro as well as a list of reference literature. We included trials assessing muscle exercise in patients with muscular dystrophy. Two reviewers independently abstracted data and appraised risk of bias.

RESULTS

We identified five small (two controlled and three randomized clinical) trials comprising 242 patients and two ongoing randomized controlled trials. We were able to perform two meta-analyses. We found an absence of evidence for a difference in muscle strength (MD 4.18, 95% CIs - 2.03 to 10.39; p = 0.91) and in endurance (MD -0.53, 95% CIs -1.11 to 0.05; p = 0.26). In both, the direction of effects favored muscle exercise.

CONCLUSIONS

The first included trial about the efficacy of muscular exercise was published in 1978. Even though some benefits of muscle exercise were consistently reported across studies, the benefits might be due to the small size of studies and other biases. Detrimental effects are still possible. After several decades of research, doctors cannot give advice and patients are, thus, denied basic information. A multi-center randomized trial investigating the strength of muscles, fatigue, and functional limitations is needed.

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.

Role of the cytoskeleton in muscle transcriptional responses to altered use

In this work, the interaction between the loss of a primary component of the skeletal muscle cytoskeleton, desmin, and two common physiological stressors, acute mechanical injury and aging, were investigated at the transcriptional, protein, and whole muscle levels. The transcriptional response of desmin knockout (des(-/-)) plantarflexors to a bout of 50 eccentric contractions (ECCs) showed substantial overlap with the response in wild-type (wt) muscle. However, changes in the expression of genes involved in muscle response to injury were blunted in adult des(-/-) muscle compared with wt (fold change with ECC in des(-/-) and wt, respectively: Mybph, 1.4 and 2.9; Xirp1, 2.2 and 5.7; Csrp3, 1.8 and 4.3), similar to the observed blunted mechanical response (torque drop: des(-/-) 30.3% and wt 55.5%). Interestingly, in the absence of stressors, des(-/-) muscle exhibited elevated expression of many these genes compared with wt. The largest transcriptional changes were observed in the interaction between aging and the absence of desmin, including many genes related to slow fiber pathway (Myh7, Myl3, Atp2a2, and Casq2) and insulin sensitivity (Tlr4, Trib3, Pdk3, and Pdk4). Consistent with these transcriptional changes, adult des(-/-) muscle exhibited a significant fiber type shift from fast to slow isoforms of myosin heavy chain (wt, 5.3% IIa and 71.7% IIb; des(-/-), 8.4% IIa and 61.4% IIb) and a decreased insulin-stimulated glucose uptake (wt, 0.188 μmol/g muscle/20 min; des(-/-), 0.085 μmol/g muscle/20 min). This work points to novel areas of influence of this cytoskeletal protein and directs future work to elucidate its function.

Resistance training in patients with limb-girdle and becker muscular dystrophies

INTRODUCTION

In this study we investigated the effect of strength training in patients with limb-girdle muscular dystrophy (LGMD) and Becker muscular dystrophy (BMD).

METHODS

In 2 studies we compared the effect of low-intensity training (LOIT; n = 8) and high-intensity training (HIT; n = 4) in muscles of the upper and lower extremities. Patients were tested for maximal strength and endurance before and after the training program.

RESULTS

LOIT training over 6 months resulted in increased biceps strength and endurance. HIT training increased endurance and strength in wrist flexion and extension and in elbow flexion. One patient discontinued HIT training due to muscle soreness and mildly increased plasma CK levels without strength deterioration.

CONCLUSIONS

Both LOIT and HIT increased muscle strength and endurance in some of the muscles tested and were well tolerated in most patients. Our findings suggest that supervised resistance training may be considered in the management of patients with LGMD2 and BMD.

Exercise and Duchenne muscular dystrophy: toward evidence-based exercise prescription

To develop a rational framework for answering questions about the role of exercise in Duchenne muscular dystrophy (DMD), we focused on five pathophysiological mechanisms and offer brief hypotheses regarding how exercise may beneficially modulate pertinent cellular and molecular pathways. We aimed to provide an integrative overview of mechanisms of DMD pathology that may improve or worsen as a result of exercise. We also sought to stimulate discussion of what outcomes/dependent variables most appropriately measure these mechanisms, with the purpose of defining criteria for well-designed, controlled studies of exercise in DMD. The five mechanisms include pathways that are both intrinsic and extrinsic to the diseased muscle cells.

Aging with muscular dystrophy: pathophysiology and clinical management

Major advances in the fields of medical science and physiology, molecular genetics, biomedical engineering, and computer science have provided individuals with muscular dystrophy (MD) with more functional equipment, allowing better strategies for improvement of quality of life. These advances have also allowed a significant number of these patients to live much longer. As progress continues to change management, it also changes patients' expectations. A comprehensive medical and rehabilitative approach to management of aging MD patients can often fulfill expectations and help them enjoy an enhanced quality of life.

Rehabilitation management of neuromuscular disease: the role of exercise training

This paper summarizes the current state of knowledge regarding exercise and neuromuscular diseases/disorders (NMDs) and reviews salient studies in the literature. Unfortunately, there is inadequate evidence in much of the NMDs to make specific recommendations regarding exercise prescriptions. This review focuses on the role of exercise in a few of the specific NMDs where most research has taken place and recommends future research directions.

Eccentric exercise in patients with chronic health conditions: a systematic review

PURPOSE

The capacity of eccentric actions to produce muscle hypertrophy, strength gains, and neural adaptations without stressing the cardiopulmonary system has led to the prescription of eccentric training programmes in patients with low tolerance to exercise, such as elders or those with chronic health conditions. The purpose of this systematic review was to analyze the evidence regarding the effectiveness and suitability of eccentric training to restore musculoskeletal function in patients with chronic diseases.

SUMMARY OF KEY POINTS

Relevant articles were identified from nine databases and from the reference lists of key articles. Articles were assessed to determine level of evidence and scientific rigour. Nine studies met the inclusion criteria. According to Sackett's levels of evidence, 7 studies were graded at level IIb, 1 study at level IV, and the remaining study at level V. Articles were also graded for scientific rigour according to the PEDro scale. One study was rated as high quality, 4 studies were rated as moderate, and 2 studies were graded as poor quality.

CONCLUSIONS

Eccentric training may be safely used to restore musculoskeletal function in patients with some specific chronic conditions. However, the heterogeneity of diseases makes it very difficult to extrapolate results and to standardize clinical recommendations for adequate implementation of this type of exercise. More studies are needed to establish the potential advantages of eccentric training in chronic conditions.

Muscular dystrophies: influence of physical conditioning on the disease evolution

PURPOSE OF REVIEW

To summarize the current knowledge of the effects of physical activity on muscular dystrophies.

RECENT FINDINGS

Although the usefulness of exercise training in muscular dystrophy patients has been debated for many years, only a limited number of articles addressing this issue have been published to date. Existing studies on the effects of strength training in patients with muscular dystrophies have shown promising results, but interpretations are hampered by several methodological shortcomings.

SUMMARY

The scientific basis for solid recommendations of different exercise regimens in muscular dystrophies is poor, but existing data suggest beneficial effects of adopting an active lifestyle. Low- to moderate-intensity resistance and aerobic training may be recommended in slowly progressive myopathic disorders. To date, there is no evidence to support the recommendation of high-resistance exercise regimens over low-moderate intensity exercise. In rapidly progressive myopathies, which are due to aberrant structural proteins such as Duchenne muscular dystrophy, the use of high-resistance and eccentric training should be avoided. There is still, however, no evidence that physical training can influence the evolution of muscular dystrophies in the long term.

Response to resistive strengthening exercise training in humans with neuromuscular disease

The role of strengthening exercise to potentially improve weakness and the functional abilities of persons with neuromuscular diseases is controversial. There are questions about the ability of diseased skeletal muscle to respond to resistance exercise, particularly in light of concerns about weakness induced by exercise. Numerous studies show promising results of strength training, although methodologic issues limit conclusions. This article reviews current knowledge in this area and provides recommendations for future investigations.