How to get knife-like abs
Hanging leg raises are one of the best ab exercises.
Hang from the bar (I often hang it on the door frame at home), raise your legs above horizontal, hold for a second and then slowly lower them.
Inhale as you lower your legs and exhale as you lift them up.
Repeat 12 times, three times a day. For maximum training effect, make sure your hips are slightly forward.
