| This is one of those crunch exercises that you don't want to rush. It's only effective if you take your time with the movement. Jerking yourself up won't have much impact. On the negative (way down) it's also very important to go a bit slower (1/2 to 1 second). To increase the level of difficulty, grab and hold a 10lb weight plate while doing the exercise movement. This exercise looks deceivingly simple, but getting the mechanics of the movement correct may take a few practice repetitions. Thus, take your time with setting up on the floor properly and executing the movement well. Since this is a variation on the classic ab crunch exercise, we suggest that you do this core exercise on days when you are not doing the traditional ab crunch. Try doing a completely different core exercise on days that you do a regular crunch. This is a general rule of thumb you can follow with all core exercises. Finally, this crunch exercises can be done on the floor (on a mat) or on a flat bench. If you're a beginner, we suggest doing it on the floor because it will provide more balance. | 
