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Electrical Stimulation Can Induce Significant Muscle Damage
Full Title
Muscle damage induced by electrical stimulation
Summary
This study examined the extent of muscle damage caused by electrical stimulation (ES), particularly during isometric contractions. Using typical therapeutic settings (75 Hz, 200-400 us pulse width), ES was found to produce significant muscle damage comparable to that from maximal voluntary eccentric contractions. Indicators of damage included strength loss, increased creatine kinase (CK) levels, and delayed-onset muscle soreness (DOMS). The authors attribute the effect to the non-selective, synchronous, and spatially fixed recruitment of motor units under ES, which results in excessive localized mechanical stress. A protective adaptation was noted after repeated ES exposure 2-4 weeks later, but initial applications can be harmful if used during early recovery.