Philadelphia ? For David Kozlow, turning 40 was a major pain in the neck. And in the ankles, back, groin, shoulder and hamstrings.

A lifelong athlete, the attorney found himself approaching his 40th birthday with a laundry list of exercise-related injuries.

One of those ailments, a herniated disk in his neck, took two years of acupuncture and heat therapy to alleviate the pain.

“I still had the mind-set that I was in my 20s,” he said. “It took a few years for me to come to the conclusion that I couldn’t really do what I used to do.”

Getting older hurts – and when it comes to exercise injuries, doctors say that’s more the case than ever before. Many are seeing increasing numbers of baby boomers.

“The volume of people in their 40s, and even in their 30s, coming in with (knee) osteoarthritis is much higher than a decade ago,” said Dr. Jess Lonner, director of knee-replacement surgery at Pennsylvania Hospital in Philadelphia.

Sports injuries among baby boomers increased by 33 percent from 1991 to 1998, according to figures cited in a U.S. Consumer Product Safety Commission report. Baby boomers in 1998 suffered more that 1 million sports injuries, to the tune of nearly $19 billion in medical costs, said the report from 2000, the most recent data available.

Aging can’t be avoided, but injuries can be. And doctors say that doesn’t mean joggers must hang up their running shoes – it’s all about exercising smarter.

“The old adage ‘no pain, no gain’ should be less relevant as we age than when we’re younger,” Lonner said. “It’s a matter of being educated in how to exercise appropriately.”