The effects of bridge exercise with the abdominal drawing-in maneuver on an unstable surface on the abdominal muscle thickness of healthy adults

[Purpose] The purpose of this study was to determine the impact of a bridge exercise with an abdominal drawing-in maneuver (ADIM) performed with different surface conditions on abdominal muscle thickness. [Subjects] Thirty subjects were randomly divided into an unstable bridge exercise group (UBE group, n=15) and a stable bridge exercise group (SBE group, n=15). [Methods] After 6 weeks of performing bridge exercises accompanied by ADIM, the change in the muscle thicknesses of the transverse abdominis (TrA) and internal oblique abdominis (IOA) muscles was assessed using ultrasonography. [Results] After 6 weeks of exercise, the TrA was significantly altered in the SBEG, and the TrA and IOA were both significantly changed in the UBEG. [Conclusion] When performing bridge exercises to increase the Tra and the IO muscle thicknesses, exercising on an unstable surface is recommended.