Physiological Basis of Low-frequency Electromyostimulation, a Promising Countermeasure against Sarcopenia and Hypogravity-induced Muscle Atrophy

Abstract

Electromyostimulation plays an important role along with other means of rehabilitation and training in sports, clinical and space medicine. Many laboratories in the world are involved in the development of new modes and hardware for electrical stimulation of skeletal muscles and in the study of the physiological effects of electromyostimulation. In the clinical setting, chronic low-frequency, low-intensity stimulation is usually applied with a view to preparing muscle tissue for cardiomyoplastic surgery, correcting the state of a paralyzed muscle, and to rehabilitating patients with the hypokinetic syndrome. This review is devoted to the study of the physiological basis (mechanisms of action) of chronic low-frequency stimulation. In the early 1970s, a model of chronic low-frequency electrical stimulation of the muscles of laboratory animals was developed and widely studied. As a result of numerous studies it was established that such stimulation led to an increase in muscle performance, fatigue resistance, the activities of oxidative enzymes and other structural and metabolic markers, as well as to a sustained fast-to-slow muscle fiber transformation. Similar data were obtained in the studies of healthy volunteers. Low-frequency stimulation had a beneficial effect on the atrophied disused muscle. The review examines the advantages and disadvantages of low-frequency electromyostimulation in relation to deconditioned muscle rehabilitation.