Back pain is one of the most common medical problems affecting Americans. About 80 percent of adults experience low back pain at some point in their lifetimes. In a large survey, more than a quarter of adults reported experiencing low back pain during the past 3 months. Men and women are equally affected by low back pain, which can range in intensity from a dull, constant ache to a sudden, sharp sensation that leaves the person incapacitated. Pain can begin abruptly as a resu