Neil Wolkodoff / AP

In this handout photo provided by Rose Center for Health and Sports Sciences, Dave Brown pushes a golf cart at a golf club in Englewood, Colo., on Nov. 12, 2008. Brown is wearing equipment that measures and records his heart rate and the distance he walks to determine how many calories he burns during a round of golf.

"Some people say, 'I play better golf when I'm carrying,'" Wolkodoff said. "But this study says, 'No. A carry bag is not necessarily better.' It's not an intuitive thought for people."

• Players reached their peak heart rates at the top of two taxing, uphill holes. When they were carrying or pushing the cart, the peak heart rates went past their anaerobic thresholds, and Wolkodoff noticed a marked spike in scoring on the tougher of the two holes under these circumstances.

He attributes it to the buildup in lactic acid, which decreases fine motor skills.

Returning below the threshold took 2 minutes to 3 minutes in some cases. So, the advice is, get in better shape to increase the anaerobic threshold so you don't find yourself going over it while playing golf. Good ways to improve golf fitness would be doing intervals on a treadmill or taking a spinning class.

"Weightlifting can come into play, too," Wolkodoff said. "As you go up a hill, whether you're carrying your own body weight, or a carry bag or a push cart, the stronger your arms and legs are, the better you can make it up that hill without fatigue."

• Wolkodoff measured subjects' respiratory exchange ratio (RER), which can be used to determine which fuels — carbs or fats — are being used during exercise. The RERs for all four tests were between 0.85 and 0.88, meaning players had shifted from burning all fat to using equal amounts of fats and carbohydrates, but hadn't yet reached the point where they were burning all carbs.

It means an energy bar with the approximately the same combination of what the players are burning — like a Zone or Balance Bar — is optimal for replenishment, and probably better than pure carbohydrates, such as the apple we often see Woods eating on the course ... or a bag of pretzels.

Not that it's any knock on Tiger's diet.

"The thing with Tiger is, he's not just eating the apple," Wolkodoff said. "He's had a good meal beforehand. If he had a regular Gatorade, that's the equivalent of eating five apples. If he eats one apple per round, or one per nine, he's just doing it to add a little energy and maybe fill up his stomach."

So, is golf a sport?

Answer: It certainly is A sport, but probably not The Only sport you would need to play if you really want to get fit. But getting fit on the treadmill or in the weight room will definitely diminish fatigue on the golf course and, in turn, help you play better.

"The study shows there's significant energy expenditure in golf, more than bowling and some other sports it's been compared to," Wolkodoff said. "There are a lot of sports that don't have this level of energy expenditure."