Introduction
bowstring, tremor, shoulder girdle, tremors
SAID
Archery is a sport enjoyed by millions of people of all ages and abilities worldwide, including people with physical mobility limitations in adaptive recreational or school physical education programs [An archery shot primarily consists of three phases: 1) the stance phase; 2) the arming phase, during which the archer pulls the bowstring and pushes the bow; and 3) the sighting phase, which involves the final stretching of the bow while focusing on the target [In Japanese high schools, side-bridge exercise is performed to train the shoulder joint and shoulder girdle muscles of the pusher. This exercise resembles the shooting posture in archery and can be said to be an archery-specific exercise. Archers perform this exercise with their hands on the floor, and arm tremors often appear immediately after the start of the exercise. The tremor that appears during movement is associated with muscle activity and is caused by fatigue-related neural and mechanical mechanisms [To address this issue, we hypothesized that an analysis of arm tremors during side-bridge exercise performed under several levels of trunk inclination can reveal a threshold inclination that will exercise the slow muscle fibres associated with the tremor in archery, and that regular side-bridge exercise under these conditions will target the type of muscle fibres that are active during the sighting phase and reduce the tremor of the arm or bow. While this information is of inherent physiological interest, it can also improve the techniques currently employed in archery coaching.Therefore, in this study, we first examined various side-bridge angles to determine the extent of trunk inclination that can be performed without the appearance of arm tremor during the side-bridge exercise. Then, we conducted a randomized controlled trial involving side-bridge exercise at the previously determined trunk inclination over a 4-week period to verify whether it improved bow tremor during archery movement. The preliminary hypotheses were that a larger trunk inclination angle during the side-bridge exercise would result in greater arm tremors, and that repetitive performance of the side-bridge exercise with a trunk inclination that did not cause tremors would reduce bow tremor during the sighting phase in archery.