Electromyographic Comparison of Abdominal Muscle Activation during Sit-Up Exercise and Ab Crunch

This study was designed to compare the effects of sit-up and ab crunch exercises on muscular activity of the rectus abdominal. A pairs of surface electrodes were placed unilaterally on four quadrants of the rectus abdominal, in ten male subjects (mean and [SD] age, height and weight were 20.6 yrs [1.90], 167.00 cm [4.92] and 62.0 kg [2.45] respectively). Electromyographic (EMG) recordings were taken while the subjects performed sit-up and ab crunch exercises. The exercises analyzed were: 1) sit-up (bent knee), and 2) ab crunch (straight leg). It was hypothesized to have a specific effect on one of the four quadrants of the rectus abdominal. Statistical Analysis ANOVA on the EMG activity demonstrated significant differences between the sit up and ab crunches as well as in the four different quadrants. Further the t-test on different quadrants during the two exercises revealed that there were significant differences in epigastria and hypogastria during sit-up and ab crunch. Hence, we conclude that ab crunch is a better abdominal exercise specific for strengthening epigastria and hypogastria muscle quadrants of the rectus abdominal.