In biomechanics, recent mathematical force-fatigue models allow to predict the muscular response to functional electric stimulations and this opens the road to compute optimized electrical pulses trains. Such pulses are modeled as Dirac pulses and this leads to a sampled-data control problem. The aim of this article is to compute optimized pulses trains establishing Pontryagin-type first-order necessary optimality conditions in the frame of optimal sampled data control problem. They are implemented using numerical shooting techniques.