Step 1: Place your feet on the floor, and your hands in the TRX straps. The closer your feet are to the anchor, the more horizontal your body will be to the floor, and the more difficult the exercise will be.
Step 2: Your hands will be maintained at chest level., with your arms extended., and palms facing each other. Keep the TRX straps above your shoulders in order to avoid chafing against you while performing this movement.
Step 3: While maintaining a strong straight-line plank position with your abs, glutes, and shoulders stabilized, proceed to lower your body towards the floor. As you are doing so, proceed to open your extended arms in an arc motion, keeping a slight bend in the elbow to alleviate elbow tension.
Step 4: When you feel a good stretch in your pectoral muscles, or when your arms reach the plane of your body, begin to push your arms back together towards the starting position., all the while maintaining a solid plank position, and pivoting on your toes.
Step 5: Repeat this movement.
How to progress the exercise
Increasing the exercise difficulty occurs the closer your body is to horizontal, therefore by stepping closer to the line of the TRX anchor, you will be able to lean back more, which will make the exercise more challenging.
Because this exercise is a unilateral pull (ie: I arm at a time) , a rotational force is created through the body, which fires the (oblique) abdominals in order to keep the body stable and in proper allignment.