Influence of Current Type (Conventional and High-Frequency with Wide Pulse) and Electrode Positioning During Neuromuscular Electrical Stimulation: Implications in Rehabilitation
Electrical stimulation, Monophasic Current, Biphasic Current, M-wave, H-reflex, Wide pulse
Introduction: Neuromuscular electrical stimulation (NMES) is a technique that employs electrodes to distribute electrical current to muscles, inducing muscle contractions. This method can be applied using monophasic or biphasic currents, targeting either nerve trunks or muscle bellies. Despite studies demonstrating fatigue reduction effects when applied to muscles or directly to nerves, the optimal electrode placement strategy on the muscle belly and nerve trunk remains unclear. Another crucial parameter in successful NMES is pulse width. While studies utilizing long pulses are often conducted with monophasic currents, it is known that this current type can lead to discomfort during NMES. Thus, it is necessary to assess whether biphasic currents have the same effect. Objective: To compare the effects of NMES using long and short pulse widths associated with monophasic and biphasic currents, targeting the triceps surae muscle and the tibial nerve trunk. Methods: A randomized, controlled, crossover experimental study involving apparently healthy individuals of both male and female genders aged between 18 and 45 years. The following parameters will be evaluated: H-reflex and Mwave tests (single and double stimulation), voluntary and evoked joint torque of the triceps surae, fatigue, sensory discomfort, and neuromuscular adaptations. Expected results: Biphasic currents are expected to be more comfortable and induce less fatigue compared to monophasic currents. There will be lower fatigue and greater central contribution when long pulse width currents are applied to the nerve compared to their application with long pulse widths on the muscle belly