A narrative review of single-waveform electrical modalities (part 1): rehabilitation implications for healthcare professionals

Exercise provides multisystemic and multidimensional benefits to health and human performance. Still, the optimal parameters required to improve pain and function across various settings and populations continue to be debated. Although researchers have attempted to alter various exercise-specific kinematics to optimize principles associated with successful training, such as adaptation, overload, continuity, volume, intensity, and specificity, emerging evidence suggests that the additive effects of AC, DC, and microcurrent may accelerate performance and rehabilitation. Microcurrent elicits cellular adaptations to attenuate pain and soreness while driving tissue growth, cellular remodeling, and fat reduction associated with tissue repair and recovery. At the same time, TENS and IFC facilitate central and peripheral pain reduction associated with acute, subacute, and chronic neuromusculoskeletal conditions. In contrast, NMES and FES stimulate alpha motor neurons and the muscle fibers they innervate, improving muscle mass, strength, and composition in neurologically impaired and orthopedic patients. Often considered exercise emulators, FES and NMES induce myokines to manage oxidation, hypertrophy, angiogenesis, inflammation, and extracellular matrix, allowing muscles to perform longer, fatigue less, and recover faster, which are key parameters related to athletic performance. Electric modalities are valuable strategies to drive the peripheral and central changes necessary to make training more efficient, mainly when presented in conjunction with exercise. Given that no single electric modality has been shown to optimize pain, inflammation, repair, performance, and recovery, technologies that offer multiple waveforms may be particularly advantageous. Future clinical trials should consider this possibility further.