Surface electromyography (sEMG) The sEMG analysis of the rectus femoris, tibialis anterior and soleus muscles will be performed with the aid of the eight-channel FREEEMG® electromyograph (BTS Engineering; Italy), with a bioelectric signal amplifier, wireless data transmission and bipolar electrodes with a total gain of 2000 within a frequency of 20 to 450 Hz. Impedance and the common rejection mode ratio of the equipment are >1015 Ω and 60/10 Hz 92 decibel, respectively. Electrode placement will follow the sEMG for the Non-Invasive Assessment of Muscles guidelines. All electromyographic (EMG) data will be captured and digitized in 1000 frames/second using the BTS MYOLAB® software (BTS Engineering; Italy) and will be collected simultaneously with the gait kinematics performed by the (G-Walk) and both will be managed by the BTS® system and EMG Analyzer® software, respectively.