Starting Position: Stand in front of the anchor point and interlock the two TRX handles together (refer to TRX user instructions). Support yourself as you loop the foot cradle around the ball of your right foot. Slowly turn to face away from the anchor point. Your standing leg or stance leg should be aligned in front, but also directly in line with the anchor point. Your suspended foot should be flexed at the ankle (toes pulled towards your shin).
Bend the right knee to approximately 90 degrees. Your knees should be lined up side by side. Bend the left arm to 90 degrees at the elbow with the finger tips level with or just below your chin. Your right arm should also bend to 90 degrees, driving it back from the shoulder until the upper arm lies approximately 45 degrees from vertical. Imagine you are running.
Downward Phase: Inhale, keeping the abdominal/core muscles engaged, bend your standing knee and slowly lower your body toward the floor. As you lower down, shift the hips backwards. Keep your body weight over the heel of your standing foot. As your body lowers, the suspended leg will drive backwards. Maintain the 90 degree bend at the knee. Your right arm should drive forward from the shoulder toward the 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 keeping the 90 degree bend in the elbows. Continue lowering yourself. Keep your weight over your left heel until your right thigh and torso form a straight line with one another. Your left shinbone should aligned with or slightly ahead of the ball of your left foot.
Upward Phase: Exhale and slowly press your body upward by pushing down against the floor through your left heel. The muscle action at the knee and hip bring the body back to your starting position.
Exercise Variation (1): To increase the intensity of this exercise, move more explosively, extending the ankle, knee and hip joints to return to your start position.
Exercise Variation (2): To further increase the intensity of the exercise, move the upper extremities in a variety of directions. For example: While the lower the legs continue to move front and back, the torso and/or arms can move left and right. The torso may rotate as well.
Using the TRX as an assisted device reduces the load placed upon many joints. While this certainly can promote additional range of movement, it does necessitate additional attention to proper form.