Physical medicine is the specialty that learned to prescribe movement like a medicine.

In June 1994, the New England Journal of Medicine published a trial about frailty in very old people. Weak muscles and poor nutrition were thought to cause much of that frailty, and both seemed reversible. But nobody had carefully tested treatments aimed at them. The trial took 100 frail nursing home residents, with an average age of 87. Some did progressive weight training for ten weeks. Some took a nutritional supplement, some did both, and some did neither. Muscle strength rose by 113% in the residents who trained. It rose by 3% in those who did not. Walking speed rose by 11.8% in the trained residents. It fell by 1.0% in the others. The supplement alone did nothing for strength or frailty. Weakness in the very old could be treated with exercise.

Eight months later, in February 1995, the same journal published a trial about acute low back pain. Doctors often prescribed bed rest or special back exercises, and nobody agreed which worked better. The trial took 186 city workers in Helsinki with new back pain. One group rested in bed for two days. A second group did back exercises. The third group simply carried on with normal activity, as far as the pain allowed. The third group recovered best, at 3 weeks and at 12 weeks. It had less pain, less disability and fewer days off work. The bed rest group recovered slowest. Ordinary movement had beaten both prescriptions.

Twenty years later, in July 2015, The Lancet published a trial about getting patients moving after a stroke. Guidelines recommended early mobilisation, but the evidence behind it was weak. The trial asked whether more movement, started sooner, would help. It gave 2,104 patients either usual care or very early mobilisation, starting within 24 hours of the stroke, more often and in larger doses. A good recovery at three months reached 46% of the very early group. It reached 50% of the usual care group. Very early mobilisation did not reduce the complications of lying still either. More movement, too soon, had done harm.

These are three of the thousands of studies that shaped modern physical medicine. They taught physical medicine that weight training could make frail people in their eighties stronger, that ordinary activity beats bed rest for back pain, and that too much movement too soon after a stroke can do harm, and each time the answer was in a paper years before it was in a textbook.

It is still happening. Recently, in May 2024, Nature Medicine published a study about people whose arms and hands were paralysed by a neck injury to the spinal cord. These injuries usually leave permanent weakness. The study added electrical stimulation, delivered through the skin over the neck, to structured rehabilitation. It compared each person’s progress with the stimulation against their own progress from an equal period of rehabilitation alone. Sixty people completed the study. Meaningful gains in both strength and hand function reached 72% of them. No serious side effects were linked to the stimulation. This study had no separate control group. Stimulation had helped people move hands that injury had weakened for years. Practice follows the literature as it goes. It is a good culture. It has exactly one cost.