In archery training, side bridges are performed in a posture similar to archery shooting for training the muscles around the shoulder joint and the shoulder girdle of the pusher. The purpose of this study was to determine whether a low-tremor side-bridge exercise for 4 weeks improves bow tremor during archery movements. Participants were 20 male college students. First, we measured the tremor during side bridges performed with trunk inclinations of 25°, 40°, 55°, and 70° using an accelerometer attached to the elbow joint and identified low-tremor side bridges. The participants were then randomly divided into intervention and non-intervention groups, and the low-tremor side bridges were performed for 4 weeks. The effect of the intervention was determined by measuring the total tremor value using an accelerometer attached to the bow and changes in the median power frequency (MdPF) of the middle deltoid, upper trapezius, and lower trapezius. This intervention reduced the bow tremor and the median power frequency of the middle deltoid (p < 0.05). The findings suggested that the tremor during the archery sighting phase could be reduced by performing side bridges with a specific trunk angle for a certain period of time. This intervention was also shown to reduce the intermediate frequency of the middle deltoid. The reduced tremor can shorten the sighting phase, which can facilitate injury prevention.