http://AskTheTrainer.com/best-lower-ab-workout.html Personal Trainer Michael Behnken, MS, NASM-CPT-PES, CSCS Hanging leg raises are one of the most ugly abs exercises you can watch people perform in the local gym. Whether they are performing them on an abs chair, hanging from a bar or using these arm slings (aboriginals) the form is usually atrocious. The raising of the knee like marching does absolutely nothing for your abdominals. In order for the hanging leg raises to work your abdominals you must bring your knees towards your mouth. Try to kiss your knees as you curl your hips upwards which is a reverse crunching motion. LOWER YOURSELF SLOWLY This is where you will get the most benefit from doing hanging leg raises. The isometric and eccentric contraction of your abdominals as you hold your knees up and lower them down is tremendous work for your abs. DISCONTINUE this exercise if you experience back pain. If you are using an abs chair, make sure your lower back comes off the back rest. This means you are doing the exercise properly. If you want to lift your knees, go marching! http://AskTheTrainer.com/best-ab-exercises.html