See how the game keeps them on their toes.

By Suzanne Rust

Caty, 14-USTA-26, ITF-209; Lynn Nabors-McNally, 48, tennis pro; John McNally, 46, financial service professional; and John Jr., 17-USTA-3, ITF-95

Tennis is quite a racket for this fit family, in the best possible sense. Mother Lynn Nabors-McNally, a former WTA Tour pro and All Big Ten player, is now a busy coach; children Caty and John Jr. are highly ranked on the circuit, and father John takes time from his work schedule to travel with the kids. The McNallys wouldn't have it any other way.

The game seems to be an inherited passion. "My parents didn't push tennis on me. I just loved doing it," shares Lynn. "The same is true for my kids. I don't even talk that much about my experiences; I've always wanted it to be their thing. They grew up around the club where I teach, so they watched me quite a bit. We just started hitting balloons when they were each around 3. It was more so that I could spend time with them, but it built up from there. You never really know—turns out they've become very good at it!"

They have indeed become very, very good at it. Caty's current national standing is 26th by the United States Tennis Association (USTA) and 209th with the International Tennis Federation (ITF); John Jr. holds 3rd place with the USTA and 95th with the ITF.

But it's not just about numbers for Lynn. What she really appreciates is her children's dedication and perseverance. "They are truly hardworking. John started playing first, traveling with my husband. Sometimes Big John would tell me, 'He's not winning,' but to me it's a journey, and I'm trying to explain that to him right now," Lynn emphasizes.

"The year before last, John lost only one match the entire year. That's a lot of pressure on a young man. The next year wasn't as good, and he had to learn how to deal with that. It's not all about right now, but about how you're building up the foundation in order to be successful later in life."

As for Caty, Lynn says she is one of the most disciplined young people she knows. "Caty missed three weeks of school last year, but she never had a tutor; she did everything with her teacher and on her own, and managed to get straight A's."

Education is very important to this fit family because Lynn knows the reality of the game. "No matter what you say, any tennis player is always one fluke, one injury away from having the dream end. But your education will always be there," she says.

Caty and John Jr. say the biggest lesson they've learned from their mother is to have fun and enjoy the game. "She also told us to believe that everyone is beatable," adds Caty. While both kids spend what little downtime they have in typical teen fashion—relaxing, watching Netflix, playing basketball and hanging out with friends—they hope to go pro as they ease into adulthood, hot on the heels of their favorite players, like Roger Federer.

Lynn, who still coaches her kids, along with the help of other pros, sees the big picture. "Tennis is an incredible learning experience—the way it teaches you to deal with people and situations is truly unbelievable. The life skills my kids have developed are amazing. They're very blessed." Lynn says she would do anything to help her kids accomplish their goals. "I'm a huge believer in dreaming big, because you never know. That dream might come to fruition."

What's the hardest part of maintaining this fit family lifestyle?

I don't get to spend as much time with my kids as I would like, but I do tell them it's about quality, not quantity. I work from 6 in the morning till 10 at night. We all travel to tournaments and more. It is what it is!

Who are Caty's and John's role models?

My daughter's Twitter handle is Caty Federer, so it's all about Roger Federer. Her dream is to meet him. Caty saw him at the Open, but if she took a photo with him, she'd probably faint. She also likes Maria Sharapova. John, who is also a huge Federer fan, had the pleasure of warming him up on the court. What he portrays as a player is outstanding.

What do you feed young athletes?

They are just growing so much. They work out, they eat well, but they burn so many calories. Salads are always a must, plus lots of grilled chicken, steak or smoked sausage. They get their carbs in the form of potatoes, pasta or rice, and they drink lots of milk and water and enjoy the occasional sweet. I'm not going to say they don't eat ice cream. Some parents won't let their kids have it, but I'm not one of them!