Grasp and hang from high bar.
Raise legs by flexing hips until fully flexed. Continue to raise feet toward bar by flexing waist. Return until waist and hips are extended downward. Repeat.
Attempt to decrease shoulder flexion during movement. Rectus Abdominis and Obliques only dynamically contract if actual waist flexion occurs. With no waist flexion, Rectus Abdominis and External Oblique will only isometrically contract to stabilize pelvis and waist during hip flexion.
Waist flexion will occur earlier in lift if legs are straighter or Hamstrings are not that flexible. Also known as 'Toes-to-Bar' or ' Strict Toes-to-Bar'. See Spot Reduction Myth and Lower Ab Myth. Also Weighted Hanging Straight Leg Raise.
Movement can be made easier by Bending knees or performing exercise on incline board.
Exercise can be made more challenging by placing weight between ankles, although caution should be practiced not to accidentally drop weight onto head or body.