Different studies showed that the EMD time is related to mechanical properties of the muscle, shape, size and fiber type and presence of fatigue (7-9). These studies suggested that alteration in EMD should be expected after substantial changes in the muscle structure. In particular after an ACL reconstruction surgery, muscle tendons are are contrasting results about different tendons: reconstruction performed with the medial third of the patellar tendon did not alter EMD of the extensors muscles (11), while EMD for the flexor muscles was found altered when semitendinosus (ST) and gracilis tendons were used as graft (12).