Why I do it: Doing this straight-leg crunch works my abs, which makes rope climbs and sprinting easier. It's also a fun challenge to try to keep my legs straight.
- Lie on your back, and lift your legs and arms up, so they are extended toward the ceiling. Lift your upper back off the floor, reaching your hands toward your feet.
- Lower your legs toward the floor while reaching your arms overhead, keeping your shoulders off the mat and lower back pressed into the mat.
- Repeat the crunch motion to complete one rep.
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