Step 1: Anchor the TRX effectively and adjust the straps to short-length.
Step 2: Hold on to the Trx handle with a firm grip
Step 3: Lean backward (body inclined about 30 -45 degrees to the standing position) and elbows in line with your body.
Step 4: Externally rotate your shoulders by taking your knuckles away from your body towards your back.
Step 5: Pull your shoulder blades together while engaging your core and keeping a straight back.
Step 6: Bring your hands back together while controlling your body towards the ground.
Step 7: Repeat.
How to progress the exercise
This exercise can be made more challenging by using one leg instead of two. Also, Holding your arms crossed over your chest, as opposed to out by your sides, creates a greater stability challenge for your core.
Tip: To avoid arching your back during this exercise, focus on squeezing your glutes, as well as pulling in your abdominals, at the same time. The glutes and the abs contracting at the same time will keep your pelvis posteriorly rotated, which will keep your back flat throughout the movement.