TORONTO, July 12 (Reuters) - They have doubleheaders in baseball and think nothing of pulling double duty in tennis and golf.
Make a mistake on the ball diamond and a run might score. Fatigue might result in a double fault on the tennis court or a double-bogey on the golf course.
But on a race track such a momentary lapse could end in much more serious and painful consequences, something IndyCar drivers will be a keenly aware of this weekend for back-to-back races on Saturday and Sunday.
"It's twice as hard, I think that's the easiest way to look at it," said New Zealand's Scott Dixon. "It's physically demanding, mentally demanding, preparing yourself in your mind to know that you've got to do it again."
This year's IndyCar calendar features three doubleheader weekends (Detroit, Toronto and Houston), an unprecedented tweak to the schedule promoters hope will double the fun for fans.
But it will no doubt also double the danger for drivers, who are likely to spend as much time in Toronto hooked up to intravenous drips as they will strapped into their race cars.
Racing on a bumpy 11-turn 1.75 mile temporary circuit under a broiling Canadian summer sun that can exact a punishing toll on both drivers and machines, durability will be the key to success, if not survival, on the streets of Toronto.
"Since we already had one (doubleheader) in Detroit, we certainly understand how it works," said IndyCar series points leader Helio Castroneves. "But because we've been through one, we know it's not going to be the same.
"We don't have power steering, street courses are very bumpy. It is very physically demanding."
While motor racing is one of the world's most popular sports, there has long been a debate about drivers credentials as legitimate athletes.
Some of those views could change this weekend watching sweat-soaked drivers lift themselves out of cockpits on hands blistered from muscling 700 horsepower machines around an unforgiving layout that last year's winner American Ryan Hunter-Reay describes as a "concrete canyon."
Racing is a dangerous business and by most accounts back-to-back races have nudged the danger-metre a few notches higher.
But Derrick Walker, the IndyCar president of operations and competition, insists that driver fitness will be the least of problems team's face this weekend.
"I don't think that's a problem," Walker told Reuters. "They can do it. They train for it.
"Believe that won't be the weakest link."
While the prospect of racing on consecutive days is challenging, it is not unprecedented.
NASCAR drivers routinely race Nationwide series events on Saturday and return on Sunday for Sprint Cup races.
A few drivers have even attempted to run the Indianapolis 500 and the NASCAR Coca Cola 600 in Concord, North Carolina on the same day.
Teams will be under no less pressure than drivers to keep the cars on the track.
There will be little margin for error in Toronto where even a small mistake on the slick street circuit could take a car out of not only one race but two.
Adding more drama to the weekend will be the first Formula One style standing start for an IndyCar race since 2008.
"Hopefully there won't be too much carnage but there might be with the first standing start," said Michael Andretti, a winner seven-times in Toronto, and now team owner.
The doubleheader weekend was the brainchild of former IndyCar CEO Randy Bernard and paddock chatter maintains it is one of the big reasons he was ousted from the job last October.
Despite some pit lane grumbling, teams and drivers have tried to put a positive spin on the doubleheader format.
But the future of double race weekends beyond this season remains uncertain.
"Cautiously optimistic, not necessarily negative against it," said Walker. "I think logistically when teams know what they are doing they can work and organize themselves to be able to do it.
"But at the end of the day what is going to decide if we use doubleheaders or standing starts is, what the fan reaction is.
"If that is what they want to see, then we'll keep doing it." (Editing by Frank Pingue)