Neuromuscular Adaptations After Training in the Muscle Belly of Triceps Surae

Neuromuscular Adaptations After Training With Neuromuscular Electrical Stimulation Applied Over Nerve Trunk Compared With a Muscle Belly of Triceps Surae: Randomized Controlled Trial

This study aims to evaluate on an acute session of the central and peripheral contributions of electrical stimulation on the muscle belly of the triceps surae, electrical stimulation of the tibial nerve and voluntary exercise of the triceps surae muscle, and identify responders individuals and non-responders to stimulation of the tibial nerve. Another objective of the study is to compare the effects of conventional electrical stimulation applied to the sciatic triceps muscle, tibial nerve stimulation and voluntary exercise after eight weeks of training in healthy individuals.

A controlled randomized controlled trial will be carried out by university students, divided equally into four groups: control group (GC), long responding pulse group (PLR), non-responder long pulse group (PLNR) and pulsed current group (CP) after the acute fase of the protocol. Muscular architecture (muscle thickness, pennation angle and fascicle length) of the muscles composing the sural triceps, H-reflex and M-wave tests (central and peripheral contribution), electromyographic signals of the medial and lateral gastrocnemius muscles and sole, voluntary and evoked joint torque of the muscles composing the sural triceps and level of sensorial discomfort. The independent intervention with the neuromuscular electrical stimulation and the isometric exercises performed by the control group will be considered as an independent variable. All groups will have the dependent variables evaluated 6 times, before, during and after the intervention, which will consist of 24 sessions (8 weeks). The training with neuromuscular electrical stimulation (NMES) will be performed 3 times a week and will never be applied for two consecutive days, as well as the voluntary exercises performed by the control group.

Inclusion Criteria:

• Classified as physically active according to the INTERNATIONAL QUESTIONNAIRE OF PHYSICAL ACTIVITY,
• To practice only recreational physical activity,
• Achieve minimum torque of 30% of the (maximal voluntary isometric contraction during conventional NMES
• Be at least 3 months without practicing strength training.

Exclusion Criteria:

• Present some type of skeletal muscle dysfunction that may interfere with the tests,
• Present intolerance to NMES in the muscular or tibial nerve, Make use of analgesics, antidepressants, tranquillizers or other agents of central action
• To present cardiovascular or peripheral vascular problems, chronic diseases, neurological or muscular affections that will undermine the complete execution of the study design by the volunteer.