2019 Volume 17 Pages 25-31
Trunk stabilization exercises improve injury prevention and performance, but the effect of deep trunk muscle training for underwater competitive performance and posture has not been clarified. If trunk stability can be obtained immediately after trunk stabilization exercises, such exercises may lead to performance improvements during underwater swimming and improve lumbar lordosis alignment during swim motions. The purpose of this study was to clarify the immediate effects of deep trunk muscle training on lumbar lordosis angle and swimming speed in underwater motion. The trial examined underwater motion before and after two different types and intensities of trunk stabilization exercises (low-intensity and high-intensity). Underwater motion was observed with an underwater high-speed camera placed 7.5 m from the pool wall, while lumbar lordosis angle was measured from the angle formed by markers affixed to the Th12, L3, and S1. During the glide swim, dolphin kick, and flutter kick trials, the maximum lumbar lordosis angle was calculated. Lumbar lordosis angle and swimming speed were calculated before and after two different intensities of trunk exercise interventions. There were significant differences in lumbar lordosis angle after both exercises during all three underwater motions. The high-intensity intervention elicited a significantly lower lumbar lordosis angle during glide swim, dolphin kick, and flutter kick, while swimming velocity was also improved during glide swim and flutter kick (P<0.05). Performing trunk exercise before practice or competition may help improve competition performance by reducing underwater resistance.