Hanging leg raises on stall bars are one of the best exercises you can do for abs—One of the reasons why stall bars are an awesome tool for hanging leg raises compared to doing them hanging from a pull-up bar, is because it is almost impossible cheat. With a bar you can cheat by swinging the legs backwards for momentum, but with the stall bar, your back is supported by a wall and cheating won't be easy.
To modify, just bend the legs (hanging knee raises are slightly easier than straight leg raises). In a controlled fashion, roll your torso upwards, bringing your knees toward your torso. Slowly reverse this motion without allowing your knees to become un-tucked from your body. Don't use momentum or jerk your body at any point.
Tip for knee/leg raises—tuck your pelvis and you’ll better target your abs!
Dragon flags are one of the more serious abdominal feats of strength that you can do, and it was a signature Bruce Lee exercise for good reason—they will definitely work your abdominals to the extreme.
If performing the full dragon flag is too difficult for you, you can begin with tuck dragon flags (bend the legs as opposed to keeping them straight). If these are still too difficult, then you can focus on building strength with the hanging knee/leg raise progressions or by doing lying leg/knee raises.
Dragon Flags can also be done on a flat or decline bench.
Dragon Flag Technique Tips—Raise your feet upward until your body is almost vertical (your shoulder blades will stay planted on the ground or bench).
Keep your core tight and your body as straight as possible while pointing (heels to sky) up in the air. KEY—SLOWLY lower your feet under control until they are just above the ground or bench, or as far as you can to start. Lift your legs back up in the air again to complete a rep.
These are just a few cool things you can do using the stall bars—give them a try!