Each shoulder movement you make is the result of complex and multiple muscle actions. The primary muscles involved in horizontal flexion are your pectoralis major, or chest muscles, and your anterior deltoids, or front shoulder muscles. Horizontal flexion occurs when your arms are raised out to shoulder level and are then drawn in toward the midline of your body. This action can occur with or without the help of your elbows.
Perform the bench press using dumbbells, barbells or a Smith machine. On a weight bench, lie on your back with the weight held at arm's length. Arch your back slightly and lift your chest. Inhale, bend your elbows and lower the weight to within an inch of your chest -- do not bounce the weight off your rib cage. Exhale and drive the bar back up to full arm extension. There is a danger that you may get pinned by the weight when performing this exercise. Always have a spotter on hand to help you if you get into difficulties.
Pushups are a common body-weight exercise that require shoulder flexion. Assume a prone position on the floor with your hands placed below the chest, 1 1/2 shoulder-widths apart. Your legs should be extended so your body forms a straight line from your heels to your head. Extend your arms by pushing with your hands against the floor, then lower your chest to within an inch of the floor, letting your toes bear weight. Push back up to the starting position and repeat. Make this exercise less challenging by bending the legs so you are bearing weight on your knees rather than your toes. This exercise will strengthen your arms, chest and core.
The dumbbell fly, which illustrates the horizontal flexion of the shoulder, is an isolation exercise that targets the muscles in your chest. Isolation exercises involve movement at only one joint. Lie on your back on an exercise bench and press the dumbbells over your chest to arm's length. Rotate your wrists so that your palms are facing inward. Bend your elbows slightly but keep them rigid throughout this exercise. Open your arms and lower the dumbbells out and toward the floor. Lower the dumbbells as far as is comfortable. When viewed from above your body should form a T-shape. Squeeze your arms back together until the dumbbells touch lightly over your chest. Inhale as you lower the dumbbells and exhale as you raise them. You also can perform this exercise in a standing position using a cable machine.
The pec deck is a chest training machine found in most gyms. Although designs vary from one machine to another, the movement -- horizontal flexion -- is the same. This exercise will tone the pectoral muscles beneath your breasts to give them a little added perkiness. Sit on the machine and place your arms on the pads. Your elbows should be level with your shoulders and your upper arms perpendicular to your body. Press your arms against the pads and squeeze them together in front of your chest. Once your arms have touched, pause for a second and slowly return to the starting position.
- Anatomy of Exercise: A Trainer's Inside Guide to Your Workout; Pat Manocchia; 2009
- Bodybuilding Anatomy; Nick Evans M.D; 2006
- Encyclopedia of Bodybuilding: The Complete A-Z Book on Muscle Building; Robert Kennedy; 2008
- Jupiterimages/Photos.com/Getty Images
This article reflects the views of the writer and does not necessarily reflect the views of Jillian Michaels or JillianMichaels.com.