IDENTIFICATION OF THE DETERMINING FACTORS OF THE TAKE-OFF PHASE IN THE LONG JUMP USING 2-DIMENSIONAL BIOMECHANICS STUDY

Abstract

The analysis of the long jump explains that the long jump consists of 4 phases namely the approach, take-off, flying, and landing. A running velocity in the approach phase often cannot be accelerated optimally in the last 3 steps due to a lack of take-off accuracy and improper technique based on biomechanical perceptions. The performance-limiting in the take-off phase such as run-up speed (va), take-off speed (vt), take-off angle (αt), and the height of the center mass (tb) have not been clearly identified. Method. This experimental study with a cross-sectional approach analyzes the profile of run-up speed (va), take-off velocity (vt), take-off angle (αt), and height of center mass (tb), including their correlation to the jump performance. 15 male athletes from the group of teenagers, juniors, and senior athletes were voluntarily tested using a 2-Dimensional biomechanical image capture sagittal view, equipped with informed consent, body mass index, leg length, and running speed of 30 meters. Results. Initial acceleration (p=0.002), take-off velocity (p=0.001), take-off angle (p=0.001), height of center mass  (p=0.001) were significantly proved affected to the long jump performance (p<0.05). The farthest jump has an average speed of the last 3 steps of 8.53 m/s, a take-off velocity of 7.73 m/s, a take-off angle (22.7°), and the height of the center of mass (109cm). Conclusion. Speed acceleration in the last 3 steps, the ability to take off at high velocity, and keep the center of body mass in height position are proven to significantly affect the performance, while the optimal take-off angle is largely determined by the anthropometric profile of each athlete.