The Benefits of Knee Up Crunch Knee Up Crunches focus on the same muscle group as other forms of Sit Ups sit-ups and crunches, but to perform them, you lie flat on your back and, instead of sitting up, bring your knees up towards your face.
The Benefits of Knee Up Crunch Knee Up Crunches focus on the same muscle group as other forms of Sit Ups sit-ups and crunches, but to perform them, you lie flat on your back and, instead of sitting up, bring your knees up towards your face.