A body in motion tends to stay in motion, and a body at rest tends to stay at rest. Such is the case with your shoulder and a condition called adhesive capsulitis. Adhesive capsulitis is more commonly known as frozen shoulder, and with good reason: It can render your shoulder so stiff, it's almost impossible to button your shirt — that is, if you aren't in too much pain to get dressed in the first place.

Frozen shoulder usually begins innocently enough. Your shoulder is bothering you, so you don't use it. Sure, there's something to be said for resting an overused joint after a weekend softball tournament. But if you've injured your shoulder or are suffering from chronic shoulder pain and you don't use your shoulder for a long time, your joint will stiffen up.

From there, it becomes a vicious cycle. If your joint begins to stiffen up, it's more difficult and more painful to use your shoulder. So you use your shoulder even less. Your shoulder gets more and more stiff, and eventually, the lining of the joint gets stiff. Once that happens, you won't be able to move your shoulder much, even if you want to. It simply won't budge past a certain point because of pain and stiffness.

In general, frozen shoulder can come on after an injury to your shoulder or a bout with another musculo-skeletal condition such as tendonitis or bursitis. It can also develop after a stroke. Quite often its cause can't be pinpointed. Nonetheless, any condition that causes you to refrain from moving your arm and using your shoulder joint can put you at risk for developing frozen shoulder.

Diabetes is also a risk factor for frozen shoulder, although precisely why that's so is a subject the medical community is still researching. One theory involves collagen, one of the building blocks of ligaments and tendons. Collagen is a major part of the ligaments that hold the bones together in a joint. Glucose (sugar) molecules attach to collagen. In people with diabetes, the theory goes, this can contribute to abnormal deposits of collagen in the cartilage and tendons of the shoulder. The buildup then causes the affected shoulder to stiffen up.

Overall, frozen shoulder affects about 20 percent of people with diabetes, compared with 5 percent of people without diabetes.