1. upper-limb kinematics (6 TVcs, Smart-D, BTS Bioengineering, Italy) and dynamic surface EMG (the upper trapezius, the anterior, middle and posterior deltoids, the triceps brachii lateral head, the biceps long head, and the brachioradialisn muscles; FreeEMG 300, BTS Bioengineering, Italy). Range of movements, velocities, normalized jerk and coefficient of periodicity are calculated using the method published by Caimmi in 2008.