This stretch is aimed at the pectoralis major muscle (sternal portion in particular). Whether we are working, driving or using our mobile phones, a lot of us spend most of the day with our arms forward, which causes the pec muscles to tighten up. We end up rounding our shoulders and closing off the chest, which then causes muscle tension and discomfort in the upper back, but also restricts nerves, impairs blood flow and causes shallow breathing. Note that we are often not aware of how tight our pecs are until we start stretching them!
Place your forearm flat against a door frame, with your elbow at 90 degrees or a bit higher – find the angle where you get the strongest stretch.
If you are stretching your right pec muscle, put your right foot forward (and vice versa).
Shift your body weight forward.
Then, pivot away from the door frame.
Hold for at least one minute. After 10 seconds, you should feel you can go a bit further. Shift your body further forward and keep progressing into your stretch.
Swap sides (you can only stretch one side at a time, because you have to pivot away from the door frame).