Chuck Burr was entranced with completing a marathon.
A longtime swimmer and coach of Team Ridglea, Burr took a break from swimming about 20 years ago and focused solely on running. After completing his 10th marathon, he started developing problems in his left knee.
"I went to an orthopedic surgeon and he told me it was a torn meniscus," Burr said. "He said they could correct it, but no more running. I didn't like that."
Burr had the surgery on his knee, but he didn't believe he would never run again. So he got back into the pool. And despite what the doctors told him, Burr is running without fail again.
Constant running, including that done for marathon training, can cause wear and tear on muscles and joints.
But for some, cross training -- doing cardiovascular work in other forms -- has worked wonders.
Two of the best options are cycling and swimming, both of which can be low or high impact depending on the athlete's needs.
Burr now can't imagine not combining swimming with running.
"[The knee problems] never came back, and I attribute that to the swimming," Burr said. "It builds up the muscles around the knees so you can do both. One helps the other."
Even some of the world's top runners have looked to different types of training.
Robert Vaughan, an assistant coach with the University of North Texas track and field team, said Olympic marathoner Joan Benoit Samuelson took to pool running while recuperating from knee surgery less than three weeks before the 1984 Olympic Games in Los Angeles.
She went on to win the first women's Olympic marathon in 2 hours, 24 minutes and 52 seconds, more than a minute ahead of her nearest competitor.
Vaughan said the type of pool running Benoit did -- in the deep end of the pool where the feet can't touch ground -- is "probably closest to real running." But other cross training has its advantages.
"It's quite beneficial, especially for people who have overuse injuries," Vaughan said. Still, he said some cross training does not entirely take the place of running.
"With biking or swimming or other things, the heart doesn't know the difference but the periphery does. There are muscles involved, but they're not similar [to running] and won't be as well-trained."
Aaron Patel has been competing in marathons and triathlons for the past two years. But after his first marathon he developed a stress fracture. So Patel grabbed his wallet and bought a bicycle. He did nine more marathons after that, and has had few problems since mixing the bicycle -- and swimming -- into his workouts.
"It's just the whole benefit you get from working different muscle groups," said Patel, who is preparing for the inaugural Ford Ironman Louisville. "When you're just running, you're using the same muscles over and over. It's helping to prevent injury by strengthening other muscle groups."
IN THE KNOW
Sundance Square, Feb. 24
Registration: 6 a.m.
Marathon, half marathon, marathon relay and 10K: 7:30 p.m.
Adult 5K: 8:15 a.m.
Saturn Kids 5K: 9 a.m.