With the knees opened out to the sides, the powerful hip flexors are at a disadvantage and can't assist the movement as much as if the legs are in the center; this forces the abs to work more — and that's a good thing.
- Lie on your back with your knees open and the soles of your feet together (in a butterfly position). Lengthen your arms overhead so they are resting on the floor.
- Exhale and bring your hands and knees toward each other, performing a full-body crunch. Your shoulder blades should be off the mat as you perform a small reverse crunch, lifting your pelvis a bit off the mat. Hold this position for a moment and really feel your abs squeezing.
- Slowly lower your arms and feet back to starting position to complete one rep.
- Do as many crunches as you can in one minute.