Position: With tubing anchored at ground level, stand with your back to the acnchor point and your arm straight, holding a cable so that the thumb is pointing up. When the arm is straight, the hand should be waist high. Your posture should be exaggerated in attention, spine long, shoulder blades pulled back.
Action: Keep the elbow locked, stretching the cable until there is no slack. Pump the arm up and down, moving no more than 4-6 inches at a time. After 8 times, move the hand from side to side so that the arm is no more than straight out front or straight out from the side.
Coaching point: If you are unable to complete the reps. due to fatigue or the burn, no problem, the exercise is working and adaptation should be quick. If you find a "hot" spot at any position, hold that spot and vibrate the arm up and down an inch or less until fatigued.