The hipless crunch is an intense abdominal exercise that tries to ensure that you work your abs exclusively, rather than cheating by letting your upper body help lift your torso off the floor. Warm up before performing hipless crunches by doing five to 10 minutes of light cardio, such as brisk walking or riding an exercise bike.
Do 10 trunk twists in each direction to stretch your abdominal muscles dynamically.
Lie face up on the floor with your arms crossed on your chest.
Raise your legs so your thighs are perpendicular to the floor, your calves are horizontal and your knees are bent at 90 degrees.
Contract your abs, exhale and lift your head, shoulders and upper back off the floor, as you would for a standard crunch.
Inhale as you lower your shoulders to the floor, but keep your head in the air.
Continue for the desired number of reps, keeping your head off the floor throughout the exercise.