This exercise uses an exercise band (rubber resistance band) with or without handles, or something similar.

Sit on the floor or gym mat with your feet extended in front of you, legs straight. Loop the exercise band round your feet to shorten it to the point where there is some tension in the band even when you hold one end in each hand with hands extended forwards towards your feet. Put yourself in the Neutral Spine Position, and keep your shoulder blades in a Butterfly.

Slowly pull your hands towards you, keeping your arms tucked in to your sides, until your hands are level with the sides of your body. Then slowly let your hands move forwards towards your feet, still keeping the core engaged and the shoulder blades held back, down and towards each other.