1. Place your forearm and biceps against a door frame, keeping the arm at right angles.
2. Exhale slowly, using the near foot, step through the doorway, keeping the other arm firmly in contact with the door frame.
3. To increase the stretch you may wish to turn the opposite shoulder backwards again keeping the other arm firmly in contact with the door frame.
4. Repeat this stretch both raising and lowering the door frame arm, in order to work the different pectoral muscles.