Exercise guide
Elbow To Knee Sit Up
- Beginner
- Compound
- Rep-based
- Core
The Elbow to Knee Sit Up is a dynamic core exercise that targets the rectus abdominis and obliques through a combination of spinal flexion and rotation. It is highly effective for developing functional rotational strength and defining the midsection.
Reviewed by the Crucible team · Updated June 2026
Muscles worked
Setup
- Lie flat on your back on a mat with your knees bent and feet flat on the floor, hip-width apart.
- Place your fingertips lightly behind your ears or at your temples, keeping your elbows flared out wide.
- Engage your core by pressing your lower back firmly into the floor to eliminate any arch.
How to do it
- Exhale as you lift your head and shoulders off the floor, rotating your torso to bring your right elbow toward your left knee.
- Simultaneously lift your left foot off the floor, bringing the knee toward your chest so it meets the elbow over your midline.
- Inhale as you lower your torso and leg back to the starting position with a controlled, slow tempo.
- Repeat the movement on the opposite side, alternating sides for each repetition.
Form checklist
- Keep your elbows wide and avoid pulling on your head or neck with your hands.
- Ensure the rotation comes from your ribcage and obliques rather than just moving your arm.
- Maintain contact between your lower back and the floor during the initial lift.
- Control the descent to keep constant tension on the abdominal muscles.
Pro tips
- Focus on bringing your shoulder toward the opposite knee rather than just the elbow to ensure full trunk rotation.
- Pause for one second at the peak of the contraction to maximize oblique fiber recruitment.
Make it harder
- Keep both feet hovering two inches off the floor throughout the entire set to increase lower abdominal demand.
- Hold a small weight plate or medicine ball against your chest to add resistance to the flexion and rotation.
Frequently asked
- What muscles does the elbow to knee sit up work?
- The elbow to knee sit up primarily targets the abs and obliques, and also works the erector spinae as secondary muscles.
- What equipment do you need for the elbow to knee sit up?
- The elbow to knee sit up requires no equipment — just your body weight.
- Is the elbow to knee sit up good for beginners?
- Yes. The elbow to knee sit up is a beginner-friendly movement and a strong foundation to build on.