Figure 3. Time histories of shoulder moments and power obtained for a single player with the rackets A (plain black), B (dashed black) and C (plain gray). Vertical dotted lines delimit the four studied phases of the serve, i.e. cocking, downward acceleration, upward acceleration and early follow-through. The plain black vertical line indicates the frame of impact, for which the results of inverse dynamics were discarded. The overlapping of the curves was achieved by normalizing the durations of each phase for the three rackets.