Step 1: Lie on your back with your heels in the TRX foot cradles; legs are extended, and the TRX straps are set to about a foot above the ground.
Step 2: Engage your posteior chain (ie: glutes, lower back, hamstrings) to raise the hips and lower back off the floor.
Step 3: Maintain this raised position and proceed to pull your heels towards your buttocks.
Step 4: The shoulder blades remain in contact with the floor, and your arms are by your side pressing into the floor to help stabilise your torso. As you are lifting your hips, squeeze your glutes and pull in your abdominals to avoid overusing the lower back muscles.
Step 5: Keep your hips raised as you return as you extend your legs back out, in a controlled manner.
Step 6: Repeat the movement several times.
How to progress the exercise
Progressing this exercise from holding onto both TRX handles, to holding only one of the handles, creates more challenge to this movement. If you start with holding the handle that is opposite to the squatting leg, you may feel more stable than if you held onto the handle on the same side as your squatting leg. Incorporate a BOSU or balance disc under your foot for more difficulty
Tip: Care must be taken in order to avoid compensating in this exercise. If your hips, knees and ankles are not aligned in a straight line throughout the movement, too much force can be placed on the hips or knees, resulting in joint problems. So, Quality over quantity is important here.