Roll Down
This video from body balance has great detail and really impressed me. I have done exercises to open the chest with a band and/or stick but never added it to the roll down to get the clients to focus on this detail. Another point I would like to add is that forcing the chin into the chest will also cause closure of the chest. When cued to tuck the chin, it is just a slight tilt to protect the neck; forcing it can cause strain in the back of the neck and bring the shoulders forward. To vary this exercise you can extend the legs out on the floor or elevate one leg when doing the roll down. Just make sure you do both sides when elevating one leg, this really allows you to be aware of the muscle imbalance of your abdominals. Reasoning is that you are mainly using one side of the rectus abdominals and the more challenging side is your weaker side.