We're opting for a one-arm pec stretch for today’s warm-up to safely and effectively stretch our pectoral muscles without putting undue stress on our shoulder capsule. All you need is a wall or doorway to perform this simple stretch. A 30-second hold per side will suffice. Start inside a doorway, with one hand in contact with the door and your arm fully extended overhead. Lower your elbow until it's at 90 degrees. Slightly lean forward and turn your head away from your arm to increase the effectiveness of the stretch. Hold for 30 seconds before switching sides.