Baseball fans looking over the equipment list — balaclavas, tights, parkas, and hand warmers — are forgiven if they think the Phillies and Yankees are headed for a ski vacation.

The World Series begins Wednesday, the latest start in the game's history at Oct. 28. Odds favor some frigid nights of baseball with bundled-up players trying to keep their heads in the game.

"The cold is an added burden on top of all the other things that are already there," said Michael Stadler, a psychologist at the University of Missouri and author of the book The Psychology of Baseball.

"You could imagine that leading to a lapse of some sort."

Technological help
Major League players are exceptionally good at focusing their attention on the game, but everyone has a breaking point, Stadler said.

"I know this: It's tough to play in cold weather," Philadelphia Phillies manager Charlie Manuel said in a press conference before Game 3 of the National League Division Series against the Colorado Rockies in Denver, which had game-time temperatures in the 30s.

A new generation of cold weather gear is designed to make the weather a non-issue.

Among the conspicuous new duds sported on the field are so-called "Elmer Fudd" downflap caps that keep players' ears and necks warm.

New Era, official headgear supplier to Major League Baseball, debuted the hats on the field during the 2008 World Series. Teams recently whipped them out again to cope with the raw October conditions.

The company also makes a knit-cap similar to a ski hat, and a balaclava that tightly fits over the entire neck and head with an opening for the face.

"You never even have to take it off," Stadler said of the balaclava. "You can wear it under a batting helmet."

Nor do players have to take off the lightweight, moisture-wicking tights from Nike and Under Armour that many wear under their uniforms. Players liken the layer to a second skin.

In the dugout, players stay warm in fleece hoodies from Majestic Athletic. Some go straight for the company's hooded, down parka. Many players put a hand warmer in a pocket to keep their digits toasty.

Gas heaters blast the partial enclosures with warm air. When it's really cold, extra heaters are brought in and coffee pots join the jugs of water and Gatorade.

"Actually, the guys on the field, if you ask them today, they'll tell you that usually once a game starts, that they stay pretty warm," Manuel, the Phillies' manager, said.

Cold weather physics
All the clothes and heaters in the world, however, won't change how cold weather affects the physics of baseball, said Porter Johnson, an emeritus physics professor at the Illinois Institute of Technology.

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Greater air density is the biggest effect of colder temperatures, which allows pitchers to put more "stuff" on the ball in the form of curves and sliders, he noted. Hit balls also travel shorter distances.

"If you increase the air density by 10 percent, you increase the resistance by 10 percent and the effect is significant, especially on long balls," said Johnson, who frequently lectures on the physics of baseball.

A 10 percent difference is the difference between a midsummer game played in 86 degree weather and a late October game in freezing temperatures, he said.

A 400-foot home run on a hot day would have to be the equivalent of a 440-foot blast on a freezing day. "There are very few homers that clear the fence by 10 percent," Johnson said.

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Manuel, the Phillies manager, noted another drawback to hitting in the cold: "It kind of stings your hand. Even though you've got gloves on, you can kind of feel it and it kind of sets in the back of your mind."

That's what Stadler, the baseball psychologist, classifies as "another distraction that they have to try and deal with."

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