Holding an 8-pound medicine ball in front of him, Sam Hornish Jr. casts a dubious glance at the container of 200 tennis balls sitting on the floor.

"We're going through that whole bucket?" Hornish asks Jim Leo, owner of PitFit Training, a program that helps race drivers and other athletes get and stay in shape.

"Hell, yeah," says Leo with the smirk of a physical trainer who knows he's about to put his client through a grueling challenge.

By this point in the workout, Hornish already has proved himself several times over. He's balanced his legs on a stability ball and pulled his torso up in a move that makes a spectator's abdomen ache in sympathy. He's hung from a bar, holding a weighted ball between his legs. He's worked with a Bodyblade, a fluttering foil about two feet long that builds upper-body muscles through resistance. He's gone a few rounds with the punching bag. Bam. Bam. Bam.

Now this:

Leo hurls tennis ball after tennis ball at Hornish. The driver swiftly reacts, fending them off with the 8-pound ball. Plunk. Plunk. Plunk. Hornish deflects them all, as the ball begins to feel heavier and heavier. Finally, the bucket is empty.

But not Hornish's reserves. He moves on to the racing simulator.

Throughout, Hornish wears a heart monitor that will let Leo know how he has withstood the workout. Like exercisers everywhere, Hornish has a goal.

The difference is that Hornish's ambition is not just to shed a few pounds or build muscles. Instead, Leo's carefully designed regimen aims to sharpen the driver's upper-body strength, reaction time and ability to focus while exhausted.

While mechanics work to make cars go faster, Leo drives clients into top physical shape so they can perform at the highest level possible.

"We sell the desire for gain and a fear of loss," Leo says. "Our goal is to take the fitness concern out of the equation. We train our drivers to be good athletes, not just good drivers."

Leo is the creator of the Indianapolis-based PitFit. His clients include a list of top drivers such as Scott Dixon, Paul Tracy and Formula One's Anthony Davidson. But not only do big-time racers benefit from Leo's guidance. Clients from prepubescent kart drivers to retirees who race for a hobby (and want to avoid having a heart attack in the driver's seat) seek Leo's instructions.

Planning own gym

For now, Leo rents space from the SportZone facility on the Northwestside. He soon plans to open his own place, geared exclusively to drivers. The new space will feature a carting track and will be equipped with high-end machines to monitor more precisely drivers' reactions under physical duress.

Technically, almost anyone could benefit from an exercise routine like the one Leo has devised for his drivers.

Not only does he recommend muscle-building routines, he also leads his charges on lengthy bike rides—preferably in the midday heat.

Peak driving form requires both cardiovascular fitness and upper-body strength. That's why trainers like Leo and others emphasize regions above the waist in their workouts.

Strength and focus

"If you're ever on a roller coaster, your body takes a beating," says Ralph Reiff, director of the St. Vincent Sports Performance Center, which also counts drivers among its clients. "We train the athletes from a strength standpoint to be able to adapt and sustain to a course so they can steer their cars well and stay focused."

For the pros, the stakes are higher. For starters, there's the chance of injury or death. There's also the prize money. The greater a driver's stamina, the more likely he or she is to be driving when the checkered flag is waved -- and the less severely injured the driver is likely to be if a crash occurs.

"Many times drivers are forced to react when they're in a very fatigued state. If you do this to someone who's fresh, great," says Leo, himself a triathlete. "Two-and-a-half hours into the Indy 500, they're worn out."

Hornish, who emerged from a dramatic flip during practice this year with only an injured knee, has new appreciation for how being in shape can offer additional protection in a crash.

"It's not always about being physically fit enough to drive the car. It's about being able to withstand injury," he says after his workout, glancing down at his wrapped knee.

But Hornish knows that physical fitness comes with myriad benefits. About 21/2 years ago, he started working with Leo. A few times a month Leo travels to Hornish's Ohio home to put him through his paces.

While a driver could opt to train anywhere with anyone, Leo's program is one of a few catering specifically to those in auto racing. He entered the field about a decade ago after working in corporate wellness, and spent years asking drivers what they thought they needed.

"You look at the needs of the sport," he says. "Anyone who thinks you can train a driver like another athlete needs to go back to school. We're auto racing 110 percent. That's who we are."

Call Star reporter Shari Rudavsky at (317)-444-6354.