Tennis elbow. Knee pain. Muscle tears. These injuries are no longer solely experienced by a younger class of athlete. More and more baby boomers are suffering serious sports-related aches and pains, or boomeritis. And while it may be a pseudo-medical term, the aches and pains are very real.

“Joint replacements used to be limited to the elderly, but not anymore,” says Asif Ilyas, M.D., an orthopedic surgeon at Temple University. “The bottom line is boomers are more active, and we’re seeing more of these high-impact injuries that are otherwise more common in a younger population.”

Census records show that baby boomers, those born between 1946 and the early 1960s, are the fastest-growing segment of the U.S. population. That means there are more middle-aged people who are living longer and participating in sports that their counterparts a generation ago might not have taken up, at least, not at the level seen today. Simply put, more baby boomers are staying active at a later age, but that activity comes at a cost. Sports injuries have become the No. 2 reason for boomers to visit their doctor, right behind the common cold, according to a 2003 survey by National Ambulatory Medical Care. A closer look at trips to the emergency room in 1998 revealed a dramatic rise: Sports-related injuries to baby boomers rose 33 percent over a seven year period, according the U.S. Consumer Product Safety Commission.

“It was very uncommon to see so many people become avid runners into their 60s and 70s a generation ago,” Ilyas said, “but it’s very common now to have middle-aged people take up such a high-endurance sport and run at a much later age.”

And with that come knee and ankle complaints and other overuse ailments. After all, a 70-year-old joint is a 70-year-old joint, and baby boomers’ bodies are simply showing their age. There is an upside, though. According to Ilyas, baby boomers are medically savvy patients who seek out treatment and are much more vigilant about their health than other populations. Finding the right balance, he said, is the best way for boomers to stay active and injury free. That means warming up regularly, not overdoing it and knowing one’s physical limitations.