Leg raises is a widely performed exercises for building ab muscles. Let’s uncover how far it serves the purpose. Doing leg raises, or holding your feet six inches off the ground or throwing your legs back down after you raise them makes your hip flexors tighter instead of working the abs and puts you at risk for back pain.
How & Why?
The muscles primarily responsible for raising the legs are the psoas muscles or hip flexor muscle, and not the abdominal muscle. The hip flexor attaches at the upper/inside portion of your thigh muscle and sits beneath your abs and intestines and runs up and attaches to your spinal column, more specifically your lumbar vertebra and disc. These muscles are a primary cause of back pain.
To prove that lying or hanging leg raises don’t specifically work the abdominal muscles; lie flat on your back as if you were performing a leg raise. Place your right hand at the top of your pubic bone and your left hand on the bottom of your rib cage. Now slowly raise your legs up to the ceiling, no more than 90 degrees. Did your hands come closer together? No!
Location & Working of Ab Muscles
The abdominal muscles attach at the bottom of the ribs and run down past the belly button and attach to the pubic bone. Remember, a muscle contracts when the two endpoints come closer together.
Only when one pulls the legs past the vertical position (90 degrees) and closer to the head, that the pelvis begins to rock up towards the head. You will begin to feel your hands move closer together. This is because you are contracting your abdominal muscles. You are doing a reverse crunch.
If you keep your hands in the same position and do a regular crunch you will notice your hands move closer together, which tells us your abdominal muscles are doing the work.
Thus, crunches and reverse crunches are some of the best exercises for working the ab muscles.
Modified Leg Raises
Start off by doing “one-leg raises” (with the other leg bent and supporting), making sure your abdominals are braced and the lower back is flat on the floor throughout. When you can do as many of these as you want with control, tension in the abdomen, and pain free, then progress to two leg raises, but lower them only to 60 degrees (lower back always flat on the floor), then 45 degrees, and so on.
Only progress if you are completely pain free and easily in control of your legs and spine.