In the present study, although the differences were not statistically significant, the SA and SL of the center of the pressure in a static standing position decreased more in the SEG than in the MEG. We attribute the greater decreases in the SA and SL of the center of the pressure of the SEG to conducting the exercise on an unstable base of support. This induces proprioceptive stimuli and activation of the whole muscles in closed kinetic chain exercise. Michael et al.9) proposed that trunk stabilization exercise using a Swiss ball enhanced the strength and balance of the trunk muscle by utilizing muscle tissues that were not usually used, and that the continuous movement of the body was needed to counter the unstable state of the trunk when using the Swiss ball. O’Sullivan et al.10) reported that performing exercise to stabilize the center of the pressure on an unstable base of support stimulated more proprioceptors and motor organs of the cerebrum than exercise on a stable base of support, maximizing the sense of balance and the balance maintaining ability, and effectively enhancing trunk stabilization. The results of the aforementioned studies demonstrate the effectiveness and the importance of exercise on an unstable base of support, including exercise with a sling.