Abstract
[Purpose] To investigate the change of whole body reaction time and muscular activity of the obliquus internus abdominis muscle in vertical jump before and after the intervention of a labored breathing exercise. [Subjects] Ten healthy men (mean age 21.6±0.7 (SD) years old) participated. [Methods] The subjects were asked to jump vertically as quickly as possible when a red light placed 2 m ahead of them was turned on. The time from the light stimulus to both feet aloft was measured and the obliquus internus abdominis muscular activity was recorded using surface electromyography before and after the labored breathing exercise. Whole body reaction time, muscle contraction starting time and muscular activity maximum time of the obliquus internus abdominis muscle were compared between before and after the intervention. [Results] The times of whole body reaction time, before and after the intervention were 342.7±28.6 msec and 329.9±25.9 msec (p<0.05). The times of muscle contraction initiation, before and after the intervention were 96.0±12.8 msec, and 84.0±19.6 msec. The times of muscular maximum activity, before and after the intervention were 170.0±25.7 msec, and 148.0±26.0 msec (p<0.05). [Conclusion] The labored breathing exercise improved the whole body reaction time and muscular maximum activity time of the obliquus internus abdominis muscle, enabling more rapid vertical jumping.
