East Jefferson General Hospital

When most of us think about the sport of tennis, the first thing that comes to mind is that it is a country club sport enjoyed by millions of people around the world. But when you get to the level of pro competition, such as what the world's best men and women players are enduring at the U.S. Open going on in New York, it brings a whole new meaning to the tennis phrase "hit and return."

Speaking as somewhat of an expert for the last five years in WTA competition, the game is all about survival of the fittest. Case in point. My client, Serena Williams, will have resting times between points of 20 seconds, followed by 90 seconds between change-overs and 120 seconds between sets.

The average match time is 1.5 hours. The female tennis player will run an average of 3 meters (3.3 feet) per shot and 8-15 meters to get a point, completing 1,300-3,600 meters per hour of play, depending on the player's status (amateur or advanced). Said female player will have about four directional changes to get a point. Female players tend to run 75 percent of the time baseline to baseline chasing the ball.

Most male and female pro players typically will exercise at 70 percent to 90 percent of their maximum heart rate. However, the intensity can elevate to near maximum heart rates during long rallies. As you can see, the high level of stress placed on the player, many times in hot, humid conditions, makes the ability to recover both during the match and between matches an important key to moving on in what I think is one of the toughest non-contact events in all of pro sports. And, let me tell you first-hand, the women's competition at the Grand Slam level is not for the faint of heart.

More to come.

- Mackie Shilstone, executive director of the Fitness Principle with Mackie Shilstone at East Jefferson General Hospital and fitness coach to Serena Williams, who advanced Monday with a 6-0, 6-0 victory.

Mackie will be filing daily reports from the U.S. Open starting Wednesday.