Effect of the Electrical Stimulation Site on Architectural Changes in Tibialis Anterior

Electrical stimulation of skeletal muscles is widely used in rehabilitation with the purpose of preserving or recovering muscle mass, improving muscle function and restoring purposeful movement after CNS damage. Electrically-induced muscle contractions can be obtained by delivering electrical pulses over a peripheral nerve trunk (nStim) or to the terminal nerve branches at the muscle level (mStim). In the last years, several types of stimulation have been developed to achieve a more “physiological” contraction that leads to fatigue reduction. This study wants to focus on architectural changes of Tibialis Anterior (TA), with regard to the fact that stimulation over the muscle (mStim) or the nerve (nStim) activate different portions of muscle. It was hypothesized that mStim would activate the upper region of TA contrary to voluntary and nStim contractions, that it is possible to evaluate an activation for the whole muscle. For this purpose, some morphometric parameters of skeletal muscle, such as Fascicle Length (FL), Pennation Angle (PA), muscle thickness was evaluated thanks to ultrasound imaging.