The present study compared the muscle activity elicited by selected abdominal training devices with muscle activity elicited by a traditional crunch. Forty-six adults participated in the study. The exercise devices tested included the Ab-ONE, Perfect Abs Roller, Ab Scissor, Ab Swing, 6SecondAbs, and the Torso Track. For those devices with variable resistances, all were tested at their high resistance setting. Surface electromyography (EMG) was recorded from the upper and lower portions of the rectus abdominis and the external oblique during each repetition. EMG values were analyzed using repeated measures analyses of variance (ANOVA) and pairwise comparisons. EMG measurements for each abdominal muscle analyzed were highly reliable and differed significantly across the exercises tested. Muscle activity for the upper and lower portions of the rectus abdominis for a normal crunch was lower than for the Ab-ONE, the same as for the Perfect Abs Roller, and higher than for the Ab Scissor, Ab Swing, 6SecondAbs, and Torso Track. External oblique muscle activity for a traditional crunch was higher than for the Perfect Abs Roller and did not differ from the other devices. These results support previous findings that portable abdominal devices are most effective if they not only mimic the mechanics of a traditional crunch, but also provide external resistance to increase involvement of the abdominal musculature.