On obvious display during the 15-day U.S. Open is the extent to which tennis players must run. The emphasis on their upper extremities aside, there is no getting around how much scampering, sprinting and scurrying is necessary.
STATS, a technology and data company using a system it calls SportVU, has done motion tracking of athletes in primary professional sports and concluded that only soccer players log more mileage in competition than tennis players.
According to SportVU, a soccer player runs as far as 9.5 miles during a game. Tennis players cover from three to five miles in a five-set match, NBA players almost three miles, football players about 1.25 miles and baseball players around 100 yards.
Perhaps it is such an acquaintance with incessant motoring that convinced Caroline Wozniacki, currently the 11th-ranked player in women's tennis, to sign up for November's New York City Marathon.
"I've always done a lot of running," Wozniacki said. "Running is a big part of my fitness already. You know, the season finishes a little early this year, so I sat down in Eastbourne and was, like, 'You know what? I have always wanted to do the New York Marathon . . . ' It's been on my bucket list for years, but I just didn't have the time."
Andy Murray, the 2012 U.S. Open champ currently ranked No. 8 among the men, recently filmed a watch commercial in which he is shown running from his Miami apartment to the tennis courts in Fort Lauderdale. In the commercial, Murray calls a cab, loads his rackets in the car, then takes off running.
"The guys I work with quite often," Murray said. "I normally run back from the courts to the apartment. It's 6.7 miles. I think I did it in, like, 47 minutes."
A marathon, of course, is 26.2 miles. "People ask me, 'Why don't you just do 5 or 10k's ?' -- because I've never done a race before," Wozniacki said. "I'm like, well, I do that every day in practice. It's not a big deal for me."
Several tennis pros with major-tournament titles on their resume have run marathons, among them Murray's current coach, Amelie Mauresmo, as well as Mats Wilander and Yannick Noah. But all did so after retiring from tennis, which is how Murray sees his long-distance running possibilities.
"I will definitely do a marathon at some stage," Murray said, "but not while I'm playing. That's an amazing effort [Wozniacki's] doing while she's playing, because it takes a lot of training. And I'm assuming she will probably want to get a good time as well. She's pretty competitive."
American veteran Sam Querrey, who needed fit legs in winning his five-set, 2-hour, 53-minute first-round Open match against Argentina's Maximo Gonzalez Tuesday, said, "I run a lot for fitness. That's the majority of my off-court fitness."
Still, Querrey said, he is "absolutely not" considering running a marathon. "I have no interest in that," he said.
Neither does 17-time major-tournament champion Serena Williams.
"This body," Williams said, "clearly is not made for a marathon runner."
Wozniacki, when the idea of taking on the New York Marathon hit her this summer, said she called her agent and asked him to find a charity she could represent. She chose the New York Road Runners' Team for Kids organization that raises funds for youth and community service programs.
"Everyone thought I was crazy," she said. "But here I am. No turning back now.
"I can do it. And you can, too."