PHILADELPHIA, Pennsylvania (AP) -- For David Kozlow, turning 40 was a major pain in the neck. And in the ankles, back, groin, shoulder and hamstrings.A lifelong athlete who played high school lacrosse and college football, ran a 5:20 mile and bench-pressed 300 pounds, 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, and I had to readjust my sights."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 with blown knees, sore backs, stiff shoulders and other complaints."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. "It's a highly motivated generation that plays harder than a generation ago."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.The highest numbers of sports-related injuries came from bicycling, basketball, baseball and running, according to the consumer report. The most common injuries come from overuse and affect knees, ankles, lower back and shoulders.Aging can't be avoided, but injuries can be. And doctors say that doesn't mean all avid joggers must hang up their running shoes, or lifelong basketball players must necessarily forgo the neighborhood court -- 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 and what signs to look out for when exercising, like muscle soreness and joint pain."For Kozlow, the solution was to switch from strenuous weightlifting to a workout that was gentler on muscles and joints. Now he does yoga and tai chi every day, strength training with light free weights and push-ups every other day, along with isometrics and elastic resistance bands. He also walks to and from work -- about a 35-block round-trip."The goal was to be pain-free and to be fit without hurting myself," said Kozlow, who didn't rely on drugs or surgery to heal his injuries. "You have to readjust your mind-set and be more attuned to your body and its limitations, which can be hard to admit."As we age, experts say, it's easier to get injured and it takes longer to heal sprains and strains. The physical changes and ailments that can come with age include loss of muscle mass, decreased bone density, diminished muscle and tendon flexibility, and joints less able to handle impact.If the idea of exercise is to keep in top physical condition, hot-dogging it on mountain bike trails or trying to relive those varsity-letter glory days in "weekend warrior" style can be counterproductive, said Dr. Vonda Wright, clinical instructor in the department of orthopedic surgery at the University of Pittsburgh School of Medicine."Many of us may still feel like we're 20, but we're not 20," she said. "Men come into my office with ruptured Achilles' tendons or muscle tears because they insist on doing the same things they did when they were much younger."Doctors recommend a physical exam, including a cardiovascular work-up, for baby boomers looking to get active or stay fit. The results can be used to tailor an individual fitness program with the lowest injury risk."It all depends on the person. If you repeatedly get banged up by being on the basketball court, you should think about getting on a bike," Wright said. "There's a time to reconsider doing extreme sports, but there's never a time to stop being active."Copyright 2005 The Associated Press. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed.