バスケットボール選手における切り返し能力に関与する力発揮の特徴

抄録

　The aim of this study was to investigate kinetic differences between penultimate foot contact (PEN) and final foot contact (FINAL) during lateral cutting maneuvers (180°turn) performed during side steps under preplanned (Pre) and unpredictable (Un) conditions. The participants were 13 players from a college female basketball team. In the experiment, participants were shown an arrow pointing either right or left on a monitor in front of them while moving with side steps toward the right. When the left arrow was shown, participants moved 3 m to the right, performed lateral cutting to the left, and moved back to the starting spot with side steps. Conversely, when the right arrow was shown, they moved 3 m by side steps to the right. The participants performed trials under 2 conditions: 1) Preconditioned: Participants were informed beforehand of the direction of the arrow signal. 2) Unconditioned: Participants responded to randomly shown arrow signals. Ground reaction force (GRF) data were collected across the PEN and FINAL phases using 2 force plates at 1500 Hz. The data in the PEN and FINAL phases were analyzed. The 2 phases were analyzed from the instant of foot strike on the force plate to the instant of toe-off during lateral cutting. Moreover, the FINAL phase was separated into FINAL braking and FINAL propulsion sub-phases. Pearson’s correlation coefficient was used to explore the relationship between the mean force for each phase and the 3-m side step shuttle time. This revealed that the 3-m side step shuttle time was correlated with the mean propulsive force at final foot contact when preconditioned, and that the mean propulsive force at final foot contact and the mean braking force at penultimate foot contact were correlated when unconditioned. In addition, the FINAL braking/PEN ratio when unconditioned was larger than that when preconditioned. Thus, under unconditioned circumstances, the mean braking force at penultimate foot contact was more important than that at final foot contact.