Instructions

1

Lie supine on a flat surface with knees bent and feet flat on the floor approximately hip-width apart. Position feet firmly on ground or have them elevated. Hands can be placed behind head with fingers interlaced or crossed over chest.

2

Engage core by drawing navel toward spine. Keep neck neutral with gaze directed toward ceiling. Ensure lower back maintains contact with floor to prevent excessive lumbar extension. Head and neck remain relaxed without pulling on neck.

3

Slowly lower torso back toward starting position by extending trunk and allowing abdominal muscles to lengthen under control. Movement is eccentric contraction of rectus abdominis as body descends. Maintain continuous tension without fully relaxing at bottom position.

4

Powerfully contract abdominal muscles to flex spine and lift shoulder blades off ground. Drive elbows toward hips while maintaining neutral cervical spine. Exhale during lift. Return to full sit-up or crunched position, squeezing abdominals at top before beginning eccentric phase.

PRIMARY MUSCLESRectus Abdominis

SECONDARY MUSCLESObliquus Externus, Obliquus Internus, Transversus Abdominis, Hip Flexors

EQUIPMENTBody weight

DIFFICULTYBeginner

Overview

If you want to isolate and overload the Rectus Abdominis, the Elbow to Knee Sit-up is an excellent addition to your routine. The mechanics of this Strength exercise specifically bias the Waist, while the use of Body weight allows for a smooth, natural resistance curve.

Benefits

Promotes balanced muscular development by effectively recruiting the Rectus Abdominis and associated synergists.
Allows for a natural movement path that closely mimics functional daily activities.
Utilizes Body weight to create sustained mechanical tension, forcing deep muscle adaptation.
Improves overall Waist stability and proprioception during heavy loads.
Acts as a highly scalable Strength movement, perfect for both beginners and elite athletes.

Common Mistakes

Losing core tension, leading to poor spinal alignment and reduced power output.
Shrugging the shoulders or compensating with secondary muscles rather than isolating the Rectus Abdominis.
Rushing the repetition tempo instead of focusing on the mind-muscle connection with the Waist.
Using excessive momentum to swing the Body weight rather than controlling the eccentric phase.

Muscle Anatomy

The primary driver is the Rectus Abdominis. However, the movement also recruits Obliquus Externus, Obliquus Internus, Transversus Abdominis, Hip Flexors to maintain control of the Body weight.

Exercise Variations

Dumbbell Elbow to Knee Sit-up
Cable Elbow to Knee Sit-up
Banded Elbow to Knee Sit-up

Beginner Tips

If you are new to the Elbow to Knee Sit-up , focus on mastering the movement pattern with zero weight before adding Body weight.

Elbow to Knee Sit-up