When you think of strength training, arm exercise may be the first thing that comes to mind. Bulging arm muscles are an icon of strength training. While arms really are one of several equally important strength training categories, arm strength is both a first line of defense against age-related loss of physical functionality and a hallmark of physical fitness. The upper arm muscles that flex the elbow joint are the most featured in exercise, although closer examination shows that the shoulder, chest, and back muscles are equally important in most upper arm motions. The humerus (upper arm bone) is connected to the scapula (shoulder bone) by a ball-and-socket joint, and so the upper arm can move in all directions governed largely by the deltoids (shoulder muscles). The biggest challenge of an arm workout is to target all 360 degrees of motion.
Bicep curls—pulling a weight towards your chest with your upper arm held nearly vertical, are the most straightforward way to exercise the biceps (front upper arm). For the triceps (back upper arm), hold a relatively light weight in each hand, stand in a leaning forward position with back straight and knees bent, lift weights first against sides of chest, and then pull weights straight behind you by extending your arm. The deltoids are engaged by any motion of the upper arm—pulling the arms up and down or back and forward. The most common of such exercises is simply lifting a weight over the head or, with equipment, pulling back down against resistance. Another great deltoid exercise is to stand up straight with relatively light weights in both hands and to lift the straightened arms away from body; the arms should come up to angles of about 80⁰ from body. Switching to elastic bands in place of weights makes a movement a little more challenging, since the band stretches as the movement progresses. A simple way to work the deltoids with absolutely no equipment is to hold arms out straight and rotate in circles of varying size and speed. Most deltoid movements will also engage the pectorals (chest muscles) and trapezius and latissimus dorsi (back muscles)—this is not only a perk to exercisers who wish to thoroughly tone their upper body but also to those who want increased upper body functionality.
The rear deltoid pulls the arm back horizontally and is probably the most neglected of the arm muscles. A LIVESTRONG.com source gives examples of rear deltoid targeting exercises: one is the “bent over lateral raise”—stand bent forward with legs shoulder width apart and knees bent, holding two weights together out in front of chest and then pulling them up and back in a semicircle (Davis 2013).
What about the lower arm? Ironically, the lower arm is not involved in very much arm movement. Rather, the lower arm muscles mostly govern the wrist and fingers. If you have done exercises for finger dexterity, you were working your lower arms. The lower arm is automatically engaged by any act of holding, lifting, or rotating an object. Therefore, most people do not need to exercise these muscles, unless they are looking to have special hand dexterity or are overcoming an injury to the hand or wrist. In a similar way, the rotator cuff muscles, which provide added support for upper arm movements, are so integral to all movements that they are not usually exercised—except in cases of physical therapy for injury.
Davis, Kristin. 20 August 2013. “Exercises to Strengthen the Rear Deltoid.” LIVESTRONG.com. (Accessed 9 August 2017). <http://www.livestrong.com/article/356487-exercises-to-strengthen-the-rear-deltoid/>.