Kinetic analysis of the lower limbs in baseball tee batting

Abstract

The purpose of this study was to investigate effects of the ground reaction forces on the rotation of the body as a whole and on the joint torques of the lower limbs associated with trunk and pelvic rotation in baseball tee batting. A total of 22 male collegiate baseball players participated in this study. Three-dimensional coordinate data were acquired by a motion capture system (250 Hz), and ground reaction forces of both legs were measured with three force platforms (1,000 Hz). Kinetic data were used to calculate the moment about the vertical axis through the body's centre of mass resulting from ground reaction forces, as well as to calculate the torque and mechanical work in the lower limb joints. The lateral/medial ground reaction force generated by both legs resulted in the large whole body moment about its vertical axis. The joint torques of flexion/extension of both hips, adduction of the stride hip and extension of the stride knee produced significantly larger mechanical work than did the other joint torques. To obtain high bat-head speed, the batter should push both legs in the lateral/medial direction by utilising both hips and stride knee torques so as to increase the whole body rotation.

Optimisation of the upper body motion for production of the bat-head speed in baseball batting

“…Determining the optimal movement patterns of the upper body could increase of the bat-head speed whilst maintaining the movement of the lower body. The lower body however contributes to the rotational movement of the body and adjustment of the swing timing (K. Ae et al, 2017Ae et al, , 2018Escamilla et al, 2009b;Welch et al, 1995). It is therefore necessary to approach a simulation analysis incorporating the lower body in further research to investigate the optimal movements of the whole body in baseball batting.…”

“…A single trial of each participant was selected from the successful trials for the development of the standard motion. The successful trials were judged by several criteria (K. Ae et al, 2017Ae et al, , 2018Ae et al, , 2020; including hitting the ball in a line drive towards a target (1.4 m × 0.7 m), the highest evaluation score of 4 or 5 (1, poor; 5, excellent).…”

“…Force and moment of the individual hands were measured with an instrumented grip-handle equipped with 28 strain gauges (1000 Hz) that had a similar structure to the instrumented bat proposed by Koike et al (2004). The marker positions were placed according to the method of K. Ae et al (2017). A global coordinate system was defined as a right-handed orthogonal reference frame as follows: the positive X direction was from the inside (medial) to the outside (lateral) of home plate for a right-handed batter; the positive Y direction was from the back (posterior) to the front (anterior) of home plate; and the positive Z direction was vertically upwards.…”

Utilization of Inertial Measurement Units for Determining the Sequential Chain of Baseball Strike Posture

“…Hence, vision and proprioception are both critical to arm the configuration and its corresponding movement. Previous studies used a motion capture system to record the rotation of the torso or analyze the ground reaction forces (GRF) during the swing for the purpose of understanding the swing skill, including swing speed of bat and adjustment of swing timing [ 13 ]. Most studies focused on the local segment of the body.…”

“…Most studies focused on the local segment of the body. For example, the visual search strategy of the athlete prior to receiving a pitched ball [ 14 ]; the horizontal head and eye movements as baseball batters take pitches and swing at baseball pitches [ 3 ]; the investigation of trunk rotation patterns during baseball batting [ 15 ]; the effects of the GRFs on the rotation of the body and the joint torques in baseball tee batting [ 13 ]; the body weight shift of batter [ 6 ]. The research of the best strike timing was based on the rotation angles [ 16 ].…”