Skeletal Muscle Damage Produced by Electrically Evoked Muscle Contractions

Abstract

Understanding the physiological/mechanical mechanisms leading to skeletal muscle damage remains one of the challenges in muscle physiology. This review presents the functional, structural, and cellular consequences of electrically evoked submaximal isometric contractions that can elicit severe and localized skeletal muscle damage. Hypotheses related to underlying physiological and mechanical processes involved in severe and localized muscle damage also are discussed.

Exercise builds the scaffold of life: muscle extracellular matrix biomarker responses to physical activity, inactivity, and aging

“…Acute electrically stimulated eccentric (5.5‐fold) and isometric (3.7‐fold) exercise can increase muscle collagen mRNA levels more than concentric exercise (2‐fold) in animals (Heinemeier et al ., 2007), but this is unexplored in humans. It is also unknown whether increased muscle collagen mRNA levels were triggered by the higher forces inherent to eccentric (and isometric) contractions, provoked by the contraction mode itself, or associated with the greater muscle and ECM damage after electrically stimulated versus voluntary contractions (Fouré & Gondin, 2021). Rat muscle collagens III and IV also follow this pattern of changes in mRNA levels after eccentric exercise (downhill running) (Han et al ., 1999 a ; Koskinen et al ., 2001 a ).…”

“…CTGF and TGF‐β1 mRNA levels in rat gastrocnemius were higher after eccentric (TGF‐β1: 10‐fold, CTGF: 2.8‐fold) and isometric (TGF‐β1: 4‐fold, CTGF: 2.3‐fold) than concentric contractions (TGF‐β1: 2‐fold, CTGF: 1.2‐fold), with this pattern also observed for LO mRNA levels. However, it is unclear whether these changes were triggered by the higher forces inherent to eccentric (and isometric) contractions, the contraction mode, or possibly the greater muscle and ECM damage observed after electrically stimulated versus voluntary contractions (Heinemeier et al ., 2007; Fouré & Gondin, 2021). Interestingly, increases in CTGF and TGF‐β mRNA levels in VL muscle were almost identical when measured 3 h after 100 eccentric knee extensions in men, with CTGF increasing 7.6‐fold and TGF‐β2 transcripts increasing 7.8‐fold (Hyldahl et al ., 2015).…”

“…Of importance is that force production during the eccentric contractions was greater than during isometric contractions, which was greater than during concentric contractions. Moreover, electrical stimulation causes greater muscle damage than voluntary contractions, which would potentially cause further ECM disruption (Fouré & Gondin, 2021). Thus, it is not immediately clear whether the between‐condition differences were unique to contraction mode, reflected muscle tensile force, or were caused by greater muscle and ECM damage.…”

“…However, force production during eccentric contractions was greater than in isometric contractions, which was greater than in concentric contractions. It is therefore not immediately clear whether between‐condition differences were contraction mode dependent due to different muscle tension or due to the greater muscle and ECM damage after electrically stimulated versus voluntary contractions (Fouré & Gondin, 2021). Nevertheless, other studies have consistently shown increased TIMP mRNA levels in animal muscles after different forms of eccentric exercise that last up to 7 days (Koskinen et al ., 2001 a , 2002).…”

Precision strength training: Data-driven artificial intelligence approach to strength and conditioning

“…Detailed review of sEMG intricacies is beyond the scope of this article, and interested readers are referred to the excellent review by Vigotsky et al [841]. Furthermore, it is also possible to to use the intramuscular or surface electrodes to drive muscle activity, known as electromyostimulation (EMS) [229], neuromuscular electrical stimulation (NMES) [237], functional electrical stimulation [399], electrical muscle stimulation [220], or electrical dry needling [199].…”