Walking upright on two feet has advantages, but it also puts intense pressure on the spine, as well as on other muscles and bones. Add to this improper sitting, lifting, or reaching—and the normal wear and tear of working and playing—and you have the perfect recipe for back pain. That’s why back pain is the second most common reason for visits to the doctor’s office, outnumbered only by upper-respiratory infections. In fact, some experts say, as many as 80% of us will experience a back problem at some time in our lives