Electromyographic comparison of a variety of abdominal exercises to the traditional crunch

Abstract

The purpose of this study was to compare a variety of abdominal exercises and abdominal exercise products to the traditional crunch to determine which exercises are most beneficial for activating the abdominal musculature. A secondary purpose was to compare upper versus lower rectus abdominis muscle activation between various exercise conditions. Fourteen subjects (6 males, 8 females) performed 5 repetitions for each exercise except for the isometric exercises where 5 second contractions were used for the abdominal exercises. The exercises that were tested were the Ab Coaster, Ab Straps, Ab Lounge, Ab Circle Pro, Ab Roller, Perfect Sit-up, Ab Rocket, Ab Wheel, stability ball crunch, bicycle crunch, yoga boat pose, side plank, front plank, decline bench curl-up, captain's chair crunch, and the traditional crunch. Surface electromyography (EMG) was recorded for the upper rectus abdominis (URA), lower rectus abdominis (LRA), external obliques (EO), and rectus femoris (RF). Electromyography between exercises was compared to the traditional crunch using a one-way ANOVA with repeated measures for each exercise. No exercises had significantly higher muscle activation than the traditional crunch for the URA and LRA. The Ab Wheel, side plank, Ab Circle Pro, and front plank had significantly lower URA and LRA muscle activation than the traditional crunch. A comparison of muscle activation between the URA and LRA found no significant difference for any of the 16 exercises with an overall EMG average of 69.6% of MVC for the URA and 67.1% of MVC for the LRA. Based upon these results it appears that the traditional crunch with the arms folded across the chest is an excellent exercise for activating the abdominal musculature. Also, the URA and LRA were shown to activate the same amount of muscle stimulation therefore it appears subject's recruit both the URA and LRA during abdominal exercises and cannot differentiate between the two.