Abstract
[Purpose] This study assessed the thickness of the transverse abdominal muscle while walking, and before and after draw-in (D). The physical responses during walking and while being aware of draw-in were also evaluated. [Subjects and Methods] We measured the thickness of the transverse abdominal muscle using ultrasonography while walking before and after draw-in. Furthermore, the measurements were performed on a treadmill (4 km/h) under three different conditions: natural walk (N), draw-in walk (D), and exercise walk (E). The three conditions were randomized. Subjects were asked to perform two tasks: task 1 was performed by 10 subjects and task 2 was performed by 20 subjects. [Results] In task 1, thickness of the transverse abdominal muscles measured before and after D were 6.1 ± 1.0 mm and 6.4 ± 1.5 mm, respectively. The difference in thickness was not significant between before and after D, implying that contraction of the transverse abdominal muscle was sustained. In task 2 the rate of consumption of oxygen (VO2) expressed relative to the body weight under the N, D, and E conditions were 11.2 ± 1.2 ml/mln•kg, 13.0 ± 2.7 ml/mln•kg, and 14.5 ± 2.2 ml/mln•kg, respectively. The VO2 significantly increased under the D and E conditions compared with N, and under the E condition compared with D. [Conclusion] The results indicated that the transverse abdominal muscle thickness were not significantly different between before and after D. This implies that contraction of the transverse abdominal muscle is sustained. Moreover, the results suggest draw-in is more effective for energy metabolism than natural walking.
