Eccentric exercise in aging and diseased skeletal muscle: good or bad?

Abstract

Evidence is accumulating regarding the benefits of exercise in people who are more susceptible to injury, such as the elderly, or those with a neuromuscular disease, for example Duchenne muscular dystrophy (DMD). There appears to be a consensus that exercise can be safely performed in aging and diseased muscles, but the role of eccentric exercise is not as clear. Eccentric (lengthening) contractions have risks and benefits. Eccentric contractions are commonly performed on a daily basis, and high-force voluntary eccentric contractions are often employed in strength training paradigms with excellent results; however, high-force eccentric contractions are also linked to muscle damage. This minireview examines the benefits and safety issues of using eccentric exercise in at-risk populations. A common recommendation for all individuals is difficult to achieve, and guidelines are still being established. Some form of exercise is generally recommended with aging and even with diseased muscles, but the prescription (frequency, intensity, and duration) and type (resistance vs. aerobic) of exercise requires personal attention, as there is great diversity in the functional level and comorbidities in the elderly and those with neuromuscular disease.

Skeletal muscle water T2 as a biomarker of disease status and exercise effects in patients with Duchenne muscular dystrophy

“…Increased permeability of muscle membrane is an early event in the eccentrically contracted muscle [39]. Indeed, dystrophin-deficient muscle fibers with fragile sarcolemma are more susceptible to damage than healthy muscle [40]. Large rises of plasma creatine kinase enzyme levels, an indirect indicator of muscle membrane leakiness, have been observed after eccentric (muscle elongates in response to a greater opposing force) but not concentric (muscle shortens thereby generating force) muscle activity in healthy individuals [41].…”

Effects of aging, exercise, and disease on force transfer in skeletal muscle

“…Force transmission is fundamental to muscle function, maintaining sarcolemmal integrity, and protection from contraction-induced muscle injury. There is, however, limited research on how force transmission proteins respond to exercise and how much they contribute to the loss of strength and increased susceptibility to contraction-induced muscle injury during aging (13,18,50). A better understanding of the components within muscle that transfer force will aid in reducing muscle injury and maintaining muscle strength, resulting in better quality of life for the elderly.…”

Aquatic therapy for children with Duchenne muscular dystrophy: a pilot feasibility randomised controlled trial and mixed-methods process evaluation

“…Although there is still the need for further research, there is general agreement that exercise that contains a substantial eccentric component (such as trampolining, stair descending) should be avoided because of the risk of exacerbating muscle damage. 38 Physiotherapy plays its part in the holistic, multidisciplinary management of children with DMD, providing specialist assessment, physiotherapy prescription and ongoing monitoring and evaluation of a complex and progressive condition. 28 Liaison with other specialist services, such as orthotics, wheelchair services, social and housing services, and schools to ensure the provision of appropriate equipment and support in a timely manner to maximise function and independence wherever possible is key.…”