This study aims to compare the knee extensors' mechanical, morphological and myoelectric properties between subjects affected by anterior knee pain and a healthy control group. The investigators hypothesis is that patients with anterior knee pain present a reduction in the knee extensors' mechanical, morphological and myoelectric properties due to chronic muscle inhibition produced by the syndrome. In addition, the study also aims to evaluate whether there are differences in methodology for application of the Interpolated Twitch Technique for evaluation of the quadriceps muscle inhibition by comparing the use of supramaximal electrical stimulation on the femoral nerve (gold standard) with stimulation on the motor point (new methodology) in healthy subjects and individuals affected by anterior knee pain. The investigators hypothesis is that the stimulation on the motor point is less discomfortable than on the femoral nerve and muscle inhibition results are less variable (with lower dispersion) due to such lower discomfort