Hang it, raise it, abs only.
Stop the swing, control on the way down is where the abs really work.
The straight-leg version of the captain's chair raise is a serious jump in difficulty, keeping your legs long moves the load far from your hips, so your abs have to produce much more force to bring them to parallel and, crucially, to control them back down. The pads take your bodyweight through the forearms, so the set ends when your core gives out, not your grip. This is the move that separates people who do ab work from people who have strong abs.
Substantially. Straight legs put the weight of your entire lower body on a long lever, so if knee raises are your current max, expect your leg raise reps to be a fraction of that at first, bend your knees slightly as a bridge.
You are dropping them instead of lowering them. The slow descent is where the abs work hardest, take 2 to 3 seconds down and pause at the bottom, and the swing disappears along with half your reps.
This is one of the better moves for that region, because raising straight legs from a hang demands a strong pelvic curl. Focus on tilting your pelvis up as the legs rise rather than purely lifting from the hips.
