Why are hanging knee raises so hard?

In addition to using the abs, hanging leg raises rely heavily on the serratus anterior for stability , which has a huge effect on the entire abdominal region. You’ll also get additional grip, arm, and shoulder work just by hanging from the bar. Sadly they’re also one of the most commonly butchered exercises.

The hanging leg raise is a tough exercise , so if you’re struggling with the full version you can make it a little easier by bending your knees as you lift your legs. You can also switch to this variation halfway through a set if the full hanging leg raise starts to become too difficult.

Two ways to progress come to mind if you are able to do slow and controlled lifts to 90 degrees.

The leg raise is a more advanced progression from knee raises since the lifter must raise the entire weight of the leg (instead of the upper thigh only), making this movement more demanding on the abdominal muscles and lifter’s ability to control their core and movement.

It depends upon your fitness goals. Leg raises are better at working the deeper hip flexor muscle group, while situps emphasize the more superficial abdominal muscles.