In terms of average percentage of the 15 patients Elasticity varies: DS from 1.23% + / - 0.13 at T0 to 1.01% SD + / - 0.01 at T1 in the muscle relaxed; DS from 1.27% + / - 0.29 at T0 to 1.04% SD + / - 0.12 at T1 in muscle during contraction.