While many middle-aged people feel young, many continue to enjoy their athletic pursuits while pulling their no-longer-20-something bodies along with them.
"This is the first time we have a generation who expects to live longer, wants to stay active and who have high expectations that they can be cured when injured," Dr Nicholas DiNubile, an orthopaedic surgeon at the Hospital of the University of Pennsylvania, USA, says.
"Middle-aged patients are a lot more demanding now, partly because of their own expectations and partly because they know the surgical technology to fix things is available," agrees Dr Bruce Reider, professor of orthopaedic surgery and director of sports medicine at the University of Chicago.
"Twenty years ago, when people in their 40s or 50s tore a knee ligament, they left it alone. Now, people at the same age want the knee reconstructed so they can resume skiing or basketball," he says.
'From grapes to raisins'
Physical activity should be applauded, of course, because it means a healthier old age, with stronger bones, muscles and hearts. Study after study has proven the benefits of exercise for physical and emotional well being as people age.
But middle-aged athletes also have to be realistic about what happens to their bodies as they grow older.
"The musculoskeletal system is subject to age," just like getting grey hair, DiNubile says.
For instance, he says, the collagen in tendons like the Achilles tendon in the heel and in the shoulder's rotator cuff weakens as we age, becoming less elastic. This leaves the tendons prone to snapping. Also, our joints lose some water content - "they go from grapes to raisins," DiNubile says - reducing their shock-absorbing ability and making them more vulnerable to injury.
The majority of sports injuries baby boomers suffer involve torn cartilage, tendons and ligaments and joint problems in knees, shoulders and other body parts subject to repetitive overuse in strenuous athletic activity.
So when a 45-year-old runner pounds the pavement the same way she did when she was 20, and ignores the swelling in her knee, eventually there's going to be trouble. The question is, how does she react when she finally goes to the doctor and hears she should moderate her activity?
"Most people respond well," Reider says of his injured patients. "But some have a difficult time accepting the fact that even with all the advances in science, we can't rejuvenate tissue and they are going to have some limits on their activities. They go from doctor to doctor, trying to find someone who will fix them so they can go back to activities as if they were 20."
If they do listen to solid advice from health professionals, DiNubile says, middle-aged athletes can remain active and injury-free. He suggests starting with a balanced, three-part workout program - strength training (using weights), endurance (aerobic exercise) and flexibility (stretching) - as a great way to maintain optimal health.
Never too late for lessons
Even returning for a few sports lessons can help, he says.
"Many overuse injuries are technique-related, like tennis elbow," DiNubile says, and by changing your grip or fixing your swing, "you can actually cure the injury."
Just learning more about how your body reacts as it ages can help you make more prudent exercise choices.
"For instance, running doesn't cause arthritis, but it will accelerate arthritis that is already there," DiNubile says. Knowing that, he suggests that you might switch to lower-impact alternatives, such as biking or swimming.
The field of sports medicine is short on research about how exercise affects the body over the long term. But that may soon change, says Dr. Peter Z. Cohen, a geriatric orthopaedic surgeon.
There are all sorts of questions that could be answered by such research, Cohen says.
"Running, for instance, greatly increases the bone density of a person over that of a couch potato, so that runners have less osteoporosis. But, at the same time, running causes undue stress on the joints and ligaments, which causes osteoarthritis, which would not affect couch potatoes," he says