Effects of the Support Surface Condition on Muscle Activity of Abdominalis and Erector Spinae During Bridging Exercises

The aim of this study was to determine the muscle activity of the abdominalis and erector spinae dur-ing bridging and unilateral bridging exercises on the firm surface, the sit-fit, and the foam roll. Eighteen healthy young subjects were recruited for this study. Surface electromyographic (EMG) activities were recorded from the both sides of the rectus abdominalis, external obliques, internal obliques, and erector spinae muscles during bridging and unilateral bridging exercises. A one-way repeated analysis of variance was used to compare the EMG activity of each muscle according to the support surface condition. Differences in the EMG activities between the bridging and unilateral bridging exercises, and between the right and left side were assessed using a paired t-test. The study showed that the EMG activities of all of the muscles were significantly higher when the bridging exercise was performed using the foam roll or sit-fit than on the firm surface. The EMG activities of the right rectus abdominis, right external obliques, the right internal oblique, and both erector spinae were significantly higher during unilateral bridging exercise using the foam roll or the sit-fit than on the firm surface. The EMG activities of all of the muscles were significantly higher during the unilateral bridging exercise than during the bridging exercise Based on these finding, performing the unilateral bridging exercise using the sit-fit or the foam roll is a useful method for facilitating trunk muscle strength and lumbar stability.