The hanging leg raise is an advanced trunk and hip flexion exercise.
 
Hang from a pull-up bar or stall bars. Without swinging, lift your straight legs up until the toes reach the bar, tightening the abs to curl the pelvis up as you would in a crunch so the motion is not simply hip flexion.
 
Return the legs to the hanging position under control.
 
To scale the motion, bend the knees and/or perform only partial lifts.
 
Notes
Using stall bars is ideal because the upper body will remain still and swinging will be impossible. If performing from pull-up bars, control the speed to minimize swinging.
 
Purpose
The hanging leg raise strengthens the abs in trunk flexion, and the hip flexors through a long range of motion.
 
Programming
Hanging leg raises can be performed in sets of 10-30+ reps. Strong athletes can add weight with ankle weights or holding a dumbbell between the ankles.
 
Variations
The speed of the movement can be changed and a pause can be added, usually with the legs horizontal. Partial raises or raises with bent knees can be used to progress athletes to the full movement if necessary. Slow eccentrics can also be used.