HOW: Get a band or cable anchored somewhere between waist and shoulder height. While standing perpendicular to the anchor and holding the handle with both hands directly in front of you, take a step away from the anchor, then raise your arms completely overhead. Lower your arms back to starting position in a slow and controlled fashion then take a step towards the anchor and repeat. Keep your hips and shoulders square facing forward the entire time.
FEEL: You should feel your core and shoulder muscles working to maintain optimal position and form. If too easy you can walk further away from the anchor, if too difficult move closer towards the anchor.
COMPENSATION: Do not let the band rotate your upper body, keep your arms straight and hips facing forward.