Referred to by some trainers as the "holy grail" of ab training, hanging leg raises test your abs, hip flexors and grip. If you don't have the finger strength, or a bar to hang from, you still have options to train your body in a similar way.
If it's grip strength that's stopping you from doing the hanging leg raise, try hooking arm straps around the bar. You insert your upper arms in these hammock-like straps and then hang on with your hands to get more stability. Dangle your legs toward the floor and do leg raises like you would if you were holding the bar.
Substitute any of these for hanging leg raises when the need arises.
The captain's chair is an apparatus that you'll find in most gyms. It looks like a very tall chair with a back and arm rests, but no seat. Use the pegs to climb up into it and lean against the back rest as you prop your weight on your elbows and forearms.
If you're just starting out, keep your back pressed into the back of the captain's chair as you raise your knees up and down to your chest. A harder version has you flex your hips to lift your legs straight up so that they are parallel to the floor. To simulate the instability of a hanging leg raise, prop on your arms only and keep your back away from the pad.
An American Council on Exercise-sponsored study published in 2001 found the captain's chair exercise to be 212 percent more effective in training the rectus abdominis and 310 percent more effective in training the obliques when compared to the classic crunch.
Keep your shoulders relaxed as you "sit" in the captain's chair.
Lying Hip Raises
When no bar is available, lying hip raises simulate the strength required to lift your legs up against gravity. Use an incline workout bench if available to increase your effort. The floor is fine if you have no other option.
If you're on the bench, lie with your head at the high end and your legs extended downward. Hold the grips at the top of the bench, or just the sides of the bench, and press your back into the padding. Press your legs together as you raise them up until they are just above the hips. Lower with control and repeat for as many repetitions as your workout requires.
To perform the move on the floor, simply press your hands into the floor alongside your hips and raise and lower your legs, using control. Avoid swinging them, which uses momentum rather than muscle.
The V-sit doesn't directly duplicate the hanging leg raise, but it similarly activates the rectus abdominis and the illiopsoas, or hip flexors. This is an advanced exercise that requires a good foundation of strength in your abs and low back. It's not easier on your ab muscles than the hanging leg raise.
Start the V-sit by lying on your back with your arms extended overhead and legs long. Crunch up from your hips by lifting your legs straight up off the floor as you simultaneously raise your upper body and arms. Don't bend your knees or round your back as you lift. Touch your toes with your hands. Return to a lying position, press your back into the floor between each repetition.