Mechanical Factors Influencing Bending of Pole in Pole Vault

Abstract

This study aimed to determine the best indicator to evaluate the ability to bend the pole and to clarify the mechanical factors that can influence pole bending with the run-up and pole in the same settings as those in competitions. Eight male vaulters (4.60 m to 5.77 m: personal best record) participated. Three-dimensional body coordinates were obtained using a motion capture system (250 Hz). In addition, the box reaction force was measured with a force plate (1000 Hz). The results were summarized as follows: (1) The strain elastic energy in the pole (E pole) at maximal pole bending (MPB) showed higher correlation with the maximal height of the vaulterʼs center of gravity (CG) than the maximal bending rate and the maximal amount of pole bending (r = 0.94, r = 0.86, r = 0.87, respectively). (2) The larger the decrease in the translational energy and the smaller the increase in the potential energy in pole bending phase, the higher the E pole at MPB (r = − 0.87 and − 0.80, respectively). (3) The larger the moment of inertia around the CG and the upper grip at the instant where the negative peak value of the angular momentum around the CG appeared, the higher the E pole at MPB (r = 0.75 and 0.79, respectively). These results suggested that the E pole was a more desirable indicator to evaluate the ability to bend the pole. Additionally, these results can serve as a basis for the practical application of techniques, namely, the swing motion with a fully extended posture.