Hold the elastic band with one hand in front of your torso with an underhand grip. Close your elbow to your body on the moving side.
Keep the band fix with your hand on the other side
Pull a bit apart to feel the light tension of the band.
Depress your scapula and open your chest.
Engage your glutes. A light knee bend can help.

1. Pull a band apart with horizontal underarm by rotating out the upper arm. Squeeze and hold on.
2. Drive your underarm back to the original position but do not release your shoulder blades.