The effects of different support surfaces on trunk and lower extremity muscle activity in a back bridging exercise

Abstract

[Purpose] The purpose of the present study was to investigate the effects of different support surfaces on muscle activity when healthy adults performed a the back bridging exercise. [Subjects] Twenty healthy adults participated in the present study. [Methods] The subjects performed a back bridging exercise on different support surfaces (mat, balance pad, air cushion, and Swiss ball). Surface electrodes were used to record the electromyographic signal amplitudes of trunk muscles (erector spinae, obliquus externus abdominis, obliquus internus abdominis, and rectus abdominis) and lower extremity muscles (gluteus maximus, vastus medialis, semitendinosus, and soleus). The EMG data were normalized as a percentage of the maximum voluntary contraction, and were analyzed using 1 × 4 repeated measures analysis of variance. [Results] We found that the activities of the vastus medialis, semitendinosus, and soleus increased significantly when the exercise was performed on a Swiss ball, compared to their values during performance on a mat or a balance pad. No such difference was found for the gluteus maximus. [Conclusion] When the back bridging exercise was performed for stabilization, the changes in support surface did not affect the activity of the trunk muscles.