Adaptive change in electrically stimulated muscle: A framework for the design of clinical protocols

Abstract

Adult mammalian skeletal muscles have a remarkable capacity for adapting to increased use. Although this behavior is familiar from the changes brought about by endurance exercise, it is seen to a much greater extent in the response to long-term neuromuscular stimulation. The associated phenomena include a markedly increased resistance to fatigue, and this is the key to several clinical applications. However, a more rational basis is needed for designing regimes of stimulation that are conducive to an optimal outcome. In this review I examine relevant factors, such as the amount, frequency, and duty cycle of stimulation, the influence of force generation, and the animal model. From these considerations a framework emerges for the design of protocols that yield an overall functional profile appropriate to the application. Three contrasting examples illustrate the issues that need to be addressed clinically.

Changes in contractile properties of skinned single rat soleus and diaphragm fibres after chronic hypoxia

“…However, the air density in our hypobaric hypoxia is about 60% of that during normoxia, reducing the power required per breath by approximately the same amount. This situation resembles what occurs in response to chronic electrical stimulation where muscle fibres atrophy in the presence of continuous, virtually unloaded, activity [42].…”

Tongue Anatomy and Physiology, the Scientific Basis for a Novel Targeted Neurostimulation System Designed for the Treatment of Obstructive Sleep Apnea

“…Neuromuscular electrical stimulation of the skeletal muscle has been long used for increasing muscle strength, mass, and functional performance in sports and regenerative medicine (73,74). Changes reported include changes in the myofibrillar proteins expression—fatigue prone‐to‐fatigue resistance phenotype shift that results in a strengthening of the cytoskeleton; in energy production—a glycolytic‐to‐oxidative shift in the metabolic profile; in antioxidant mediated defense—an increased intracellular defense against harmful oxygen species (75); and in fiber size—small diameter‐to‐large diameters fibers shift with higher contractile tensions (76).…”

Evaluation of the neuromuscular compartments in the peroneus longus muscle through electrical stimulation and accelerometry

“…The stimulation was performed with a monopolar square pulse duration of 200 µsec. Medium pulses (~200 µsec) were utilized to ensure torque generation and to avoid muscle fatigue and nociceptor activation [24][25][26][27][28] .…”