This is a great exercise to work shoulder stabilization and the muscles of the upper and lower back. Integrate this exercise into your core routine. Muscle groups involved: Core, shoulders, low and middle back. Assume a push-up position. Shift your weight to your right hand and rotate your body, raising your right arm into the air and rotating your arms and torso to form a “T”. Hold this position for two seconds and then slowly return to the starting position. Then perform the movement on the other side. Control the motion and go slowly. Repeat as directed by your FRF workout and your level of fitness.