Starting Position: Stand in front of the anchor point and interlock the two TRX handles together (refer to TRX user instructions). Loop the foot cradle around the ball of your right foot while supporting yourself. Slowly turn to face away from the anchor point, standing on your stance leg, aligned in front, but directly in line with the anchor point. Your suspended foot should be dorsiflexed at the ankle (toes pulled towards your shin).
Adopt a modified sprinter-stance with the right leg flexed to 90 degrees, knees aligned side by side, and the left arm flexed to 90 degrees at the elbow with the finger tips level with or just below your chin. Your right arm should also be flexed to 90 degrees, driving it back from the shoulder until the upper arm lies approximately 45 degrees from vertical.
Downward Phase: Inhale and slowly lower your body towards the floor, shifting the hips backwards simultaneously and maintaining your body weight over the heel of your left foot. As your body lowers, the suspended leg will drive backwards, maintaining the 90 degree bend at the knee. Your right arm should drive forward from the shoulder towards the a end-position where the left arm started. Your left arm should simultaneously drive backwards to an end-position where the right arm started. Throughout the arm movements, squeeze the arms to the sides of your body and drive from the shoulders while maintaining the 90 degree bends. Continue to lower yourself maintaining weight over your left heel until your right thigh and torso are in parallel (form a straight line together). Your left tibia (shinbone) should move level with or slightly ahead of the ball of your left foot.
Upward Phase: Exhale and slowly press your body upwards by pushing down against the floor through your left heel. The muscle action at the knee and hips extend the body back to your starting position.
Exercise Variation (1): To increase the exercise intensity move more explosively to triple extension. The upward phase should be performed more explosively and incorporating triple extension (at the ankle, knee and hip).
Exercise Variation (2): To increase the exercise intensity move the upper extremity into different planes. While the lower extremity moves in the sagittal plane (front and back), the upper extremity and/or arms can move in the frontal (left and right) and transverse plane (rotation).