I hurt my back for the first time ever last week. When I saw my doctor she did a few tests, had me bend forward, sideways, and backwards, and sent me home with a few exercises. It may have looked like my motion was normal but for me I could tell it was very restricted. How can the doctor decide what’s normal and what’s not?

Doctors use information published in studies of normal ranges for strength and motion for men and women. These norms do change as people age but that’s taken into consideration, too. Doctors also rely on patients to tell them what’s normal for them.

A decrease of 20 percent or more for any motion (forward, backward, sideways) is considered a “positive” sign. The doctor’s exam also looks for other changes such as spinal curvature (scoliosis), leg length differences, or sensory loss.

Doctors are trained to look for red flags that point to serious problems like infection, fracture, or tumor. Most of the time, the cause of back pain is unknown. Changes in the soft tissues (muscles, ligaments, tendons) or joints can cause pain that’s referred to as mechanical.

Your doctor’s proposed treatment suggests a diagnosis of mechanical low back pain. Follow her advice and the chances are very good you’ll have a full recovery. If pain persists or you get worse, make a follow-up appointment for further testing.