Kinematic factor analysis of backstroke start movement

This study analyzed the kinematic factors of the backstroke start for male high school backstrokers and obtained the following conclusions. First, the total time required for the backstroke start movement was found to be 0.33 ± 0.03 s, with longer times in the order of section 2, section 1, and section 3. Second, the horizontal displacement of the body center during the backstroke start movement was 1.18 m for athlete b, showing the largest displacement in all directions, followed by athletes e, c, a, and d. And for the vertical displacement of the body center, player e showed the greatest displacement in the vertical direction in the total displacement (TD), followed by players b, c, d, and a. Third, the horizontal speed of the body center during the backstroke start movement was 3.75 m/s for athlete D at the moment of entering the water, showing the fastest speed compared to other athletes in all directions, and the vertical speed of the center of body at the moment of entering the water was -1.27 for athlete E. The fastest speed was in the vertical downward direction in m/s. Fourth, during the backstroke start movement, the angle of the lower extremity joint was extended according to the progress of the movement, and the range of motion of the right hip joint angle was large in the order of players e, b, c, d, and a, and the range of motion of the left hip joint angle was The range of motion was greater in the order of players b, e, c, a, and d. The right knee joint angle, like the hip joint angle, was extended according to the progress of the movement, and the range of motion was greatest for player a, followed by players b, e, c, and d. The range of motion of the left knee joint angle was greater in the order of players a, b, e, c, and d. Fifth, the projection angle during the backstroke start movement was within 0° to 1° for all athletes, and the projection speed was faster for athletes b, e, a, c, and d.