Step 1

Starting Position: Lie flat on your back on the floor / mat in a bent-knee position with feet placed firmly on the floor and your arms crossed behind your head.  Stiffen (“brace”) your abdominal muscles to stabilize your spine, depress and retract your scapulae (pull shoulders back and down).  Slowly lift both feet off the floor moving your knees towards your trunk until your thighs align vertically to the floor (90-degree angle at the hips).  Maintain a 90-degree bend at the knee and relax your feet, allowing them to point away from your body. 

Step 2

Gently exhale then begin your movement by simultaneously:

  • Drive your right knee towards your chest in a straight line and allow the knee to bend to a deeper angle.
  • Extend (straightening) your left leg outward while keeping it elevated off the floor.
  • Contract your abdominals to flex (curl) your trunk, lifting your left shoulder blade off the floor and rotating your trunk slowly to drive your left elbow towards your right knee.  This movement will press your low back into the floor / mat.  

Step 3

Continue moving until your elbow touches or comes close to touching the opposite knee.  Hold this up-position briefly for 1 – 2 seconds then slowly return to your starting position and repeat the movement to the opposite side.  Complete a set of quality reps until your experience fatigue or until your technique (form) becomes compromised.

Step 4

Important points to consider while performing this movement:

  • Perform this exercise in a slow, controlled manner
  • Do not pull forward on your head during the trunk curl.  Support your head in your hands while maintaining alignment of your head with your thoracic (upper) spine.
  • During the upward and downward movement of your trunk, it is important to keep your low back pressed into the floor / mat.
  • The rotation should come from your trunk and not your hips.  While your legs drive forward and backwards in a straight line, your trunk will flex (curl) and rotate.


To maximize the benefits of this exercise and reduce the potential for injury, it is important to control movement speed and monitor changes in your low back carefully.