Hanging Knee Raise

Move · Resistance Training · Movement, Typed Supps

The abs only really enter the movement at the end, when the pelvis curls up — everything before that is hip flexors.

Stage by stage

Set-up (Still hang, no swing): Residual oscillation supplies angular momentum that replaces the force the muscles should produce.
During the set (Iliopsoas raises the femur): Hip flexion to 90 degrees is hip flexor work; the abs hold the pelvis against lumbar extension.
Top of the rep (Posterior pelvic tilt): Curling the pelvis is spinal flexion, the only phase where rectus abdominis is the prime mover.
Weeks later (Grip endurance catches up): Forearm endurance usually limits the set before the abdominals do, so grip capacity governs early progress.

Muscles trained

Primary: hip flexors, quads
Secondary: abs, forearms, lats

Intensity

3.8 METs (Calisthenics (e.g., push ups, sit ups, pull-ups, lunges), moderate effort).

Time to effect

Weeks: Swinging decreases and the reps become noticeably more controlled as grip endurance and ab timing improve.
Months: Full range with a strong pelvic tilt becomes repeatable for higher rep counts, and ankle weights or straight-leg progressions become realistic.

Common myth

“Hanging knee raises only work the hip flexors, not the abs.” In reality: Electromyography studies on hanging leg and knee raises show real rectus abdominis activation, especially in the final phase of the rep when the hip flexors have already done most of the lifting and the abs finish the movement by tilting the pelvis backward.

In the glossary

Evidence grade