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Flexion Leg Sit Up (Bent Knee)
A bent-knee sit-up that emphasizes deliberate spinal flexion rep by rep, keeping tension on the abs while reducing hip flexor dominance.
AbsBodyweightTrunk flexion
GoLightWeight mediaflexion-leg-sit-up-bent-knee
Demonstration coming soon
Primary
Rectus abdominis
Secondary
ObliquesHip flexors
Equipment
Bodyweight
Pattern
Trunk flexion
Setup
- 01Lie on your back with knees bent about 90 degrees and feet flat.
- 02Keep the feet unanchored so the abs must do the lifting.
- 03Reach the arms forward along the thighs or cross them on the chest.
- 04Tuck the pelvis slightly to set the lower back near the floor.
Execution
- 01Exhale and curl the chin, then the ribcage, peeling the spine up one segment at a time.
- 02Continue flexing until the torso is upright over the hips.
- 03Reverse the motion, laying the spine down vertebra by vertebra.
- 04Finish each rep with the shoulder blades back on the floor.
Checkpoints
- -The spine rounds progressively; no flat-back hinging.
- -Feet stay down without anyone or anything holding them.
- -The tempo is even in both directions.
- -The abs stay contracted throughout, including the descent.
Common mistakes
- -Jerking up with straight-back momentum from the hip flexors.
- -Letting the feet fly up because the movement is rushed.
- -Collapsing down fast instead of rolling down with control.
- -Whipping the arms forward to cheat the ascent.
Programming notes
- -Use 2 to 3 sets of 8 to 15 slow, segmental reps.
- -If the feet lift, slow down and lead with more spinal flexion.
- -Hold a light plate at the chest once 15 clean reps are easy.
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