Last month we wrote about the common shoulder injury Shoulder Impingement. The other common injury to the shoulder happens in the front, where the short head of the biceps muscle attaches to the shoulder blade, a biceps tendon strain. This injury is most common in Ashtanga Vinyasa and subsequent ‘flowing’ yoga styles that incorporate a lot of Sun Salutations and chaturangas. The shoulder can’t do this action very well, and the biceps become strained before too long. 
Pectoralis major (“pec”)
PECTORALIS MAJOR & ADDUCTION
One of the biggest and most powerful muscles of the shoulder is the pectoralis major, commonly known as the ‘pecs’ or just the ‘chest muscle’, pictured to the left. It connects the arm (humerus) directly to the middle of the chest. Its main function is to pull the arm toward the chest in an action called adduction.
Try it: hold your arm out to the side (as pictured below, labeled adduction), then bring your arm toward the center, so you end up with your arm pointing forward. As you do this, you will feel your ‘pec’ engage. When you apply this motion to something like a pushup, the arms need to be away from the body, so the pushup motion will be pulling the arm inward toward the chest. Simply put, this means keeping your elbows away from the body. This is the safest way to do any pushup motion.
In contrast, if we start with our arms down by the sides and lift them up until they point forward, this is called flexion (pictured above, labeled flexion). When we lift the arm like this, the pec doesn’t get activated much, so the work is done by much smaller muscles like the anterior deltoid (the front of the shoulder cap) and the biceps. The biceps cross two joints; they bend the elbow and also flex the shoulder. But they don’t have the power to move the body’s entire weight.
When we do pushups or chaturangas with the elbows close to the sides of the body, we are essentially moving the shoulder in flexion. This is not a powerful nor particularly healthy way to move so much weight. When we do this repeatedly, the bicep tendon (usually the short head at the attachment with the coracoid process of the shoulder blade) will often be damaged. This manifests as pain or soreness in the front of the shoulder.
There is a common belief that keeping the elbows close to the body uses the triceps more than if the elbows were wider. This is not true for the simple reason that the triceps straighten the elbow, and the elbow is doing a similar action in both versions. The big impact is on the shoulder and what muscle group you use when doing a pushup or chaturanga motion.
IN CONCLUSION
There is nothing inherently wrong with keeping the elbows close to the body and flexing the shoulder. The problems arise when we do this with our entire body weight and do it repetitively. This is how injury usually happens. Consider making the elbows wider, which will strengthen the huge pectoralis major muscle as well as be safer for the smaller muscles of the shoulder.
Happy, healthy practicing!
