The nation's 78 million baby boomers have hit middle age -- the oldest boomers turn 60 this month -- but many refuse to sink into the couch and wait for old age.
Instead they run, ski and work out as hard as ever, playing the same sports they enjoyed in their 20s and 30s.
The only problem: Their bodies are not as forgiving.
Drew Coburn, 46, has already sustained 30 stitches, a broken nose, a torn shoulder muscle, a torn knee ligament, cartilage damage in both knees and a broken foot -- the result of weekly pickup basketball games.
But he still plays.
"I love it," Coburn said. "There's an attitude among all the guys out here, because they've all gotten whacked, that it's quality of life."
"Baby boomers and their injuries are the fastest growing part of my practice. It's huge," said Dr. Riley Williams at the Hospital for Special Surgery in New York City. "They keep playing, and we keep fixing them."
As an orthopedic surgeon, Williams has many new ways to fix those injuries.
For severe rotator cuff injuries, patches -- some made from pig intestines -- can reconnect the muscle to the bone.
New medical plugs can now fill the holes in worn-out cartilage, and partial knee replacement can be the answer for more extensive damage.
But the substance that attaches the replacement to the bone can wear away, so patients are usually discouraged from running on it. Many baby boomers like Coburn, who want to keep playing, have turned to an unorthodox surgery.
During a knee realignment, or osteotomy, doctors actually break the leg and reset it away from damaged cartilage.
If the inside of the knee causes the pain, the leg is repositioned so weight is carried on the outer part of the knee, and vice versa.
"It allows a return to sport without worry about any artificial part," said Williams.
Within a few month's of the operation, Coburn says his knee was like new.
"When I came back," he said, "I went from excruciating pain while I played to zero pain. It was unbelievable. It really was."
Coburn's experience is just one more way doctors are getting active baby boomers back in the game.
ABC News' John McKenzie filed this report for "World News Tonight."