Starting Position: Place your feet securely into the foot cradles positioned directly under the anchor point. Apply downward pressure with the tops of your feet by plantarflexing your ankles (point toes away from your shins). Gently lie flat on your stomach with your hands placed shoulder-width apart, under your shoulders and facing forward. Stiffen your torso by contracting your core/abdominal muscles ("bracing"), and your glutes and quadriceps (butt and thigh muscles).
Upward Phase: Exhale and slowly press yourself upward until your elbows are fully extended, aligning your head and spine (avoid any sagging or aching in your low back or hips hiking upwards). Keep your feet together throughout the exercise and avoid any back and forth swinging of the TRX straps. Slowly pull your knees toward your chest, bending your knees as they tuck under your hips, keeping your feet together and ankles in plantarflexion (toes pointed away from your shins). During this movement, your hips will rise upwards and your spine will flex (curl into a ball). Continue pulling your knees inwards until they lie directly under your hips.
Downward Phase: Inhale and slowly lower your body towards your starting push-up position, aligning your head and spine together. Avoid any arching or sagging in your low back throughout the range of motion.
Exercise Variation: The intensity of this exercise can be increased by positioning your body further away from under the anchor point of the TRX and lengthening the straps.