The teres major muscle attaches to the front of your upper arm, crosses under your shoulder and reattaches to the lower, inside portion of the scapula in your upper back. The muscle facilitates shoulder adduction, extension and internal rotation ranges of motion. Stretches for the teres major involve moving through the opposite ranges of motion -- shoulder abduction, flexion and external rotation.
This exercise lengthens and stretches the teres major through external rotation, a range of motion utilized by athletes who perform overhead arm motions frequently. Lie on your back on a flat bench with your left upper arm extended sideways, away from your shoulder, and your elbow flexed to 90 degrees, so your forearm points away from your feet. Have a partner secure your elbow with one hand and push your wrist downward with the other until you feel a gentle stretch. Have her hold this position for 10 to 30 seconds, then switch arms.
Overhead Shoulder Flexion
This exercise stretches the teres major through shoulder flexion, the opposite of extension. Stand in a door frame and reach both arms overhead, placing your hands shoulder-width apart on the wall just above the frame. Lean forward slightly, moving your head and torso in front of your hands, until you feel a light stretch. Hold for five deep breaths, deepening the stretch slightly with each exhalation.
Although side bends target the latissimus dorsi muscles on the sides of your back, they also stretch the teres major and other muscles that assist with shoulder adduction -- pulling your arms toward the center of your body. Stand upright and spread your feet wider than your shoulders. Rotate your left foot outward 90 degrees, pointing your toes sideways. Extend your right arm above your head, then lean to the left, placing your left hand on your knee. Stop when you feel tension through the right side of your torso, then hold for 15 to 30 seconds. Repeat the stretch in the opposite direction. Keep your chest and thighs directed forward as you perform the exercise.
Pavel Tsatsouline, author of "Relax Into Stretch," recommends this exercise to stretch the muscles that extend your shoulders, including the teres major. Kneel 3 to 5 feet away from a chair. Bend forward at the waist and place your hands on the seat of the chair, about shoulder-width apart. Move your head downward, between your arms, until you feel a gentle stretch. Hold for five deep breaths, pressing downward with your hands with each inhalation, then releasing the pressure and lowering your torso farther with each exhalation. Have a partner press on the middle of your back during each exhalation if you have trouble feeling the stretch.