On average, a golf ball travels 10 percent farther a mile above sea level. (PGA.com)
Mile High Challenge: Playing in altitude to test field
Determining yardages and correct club selection are a challenge for any golfer, even the best players in the world. But throw in the fact that playing in high altitude makes those calculations even more difficult, and you have a special challenge at the 71st Senior PGA Championship.
By T.J. Auclair, PGA.com Interactive Producer
PARKER, Colo. -- The star-studded field of competitors over the age of 50 teeing it up in the 71st Senior PGA Championship at Colorado Golf Club this week will face an array of challenges.
The greatest challenge of all, arguably, will be the way they're able to adjust to playing at altitude.
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Colorado Golf Club is located in Parker, Colo., in the southeastern-most corner of the Denver Metropolitan area and sits at an elevation of 5,869 feet, well over one mile high.
What, exactly, are the challenges of playing golf at altitude?
For starters, meteorologist Herb Stevens, who owns a forecasting service called Grass Roots Weather that provides forecasts for about 45 superintendents around the country, including those at Muirfield, Medinah and Congressional, said altitude makes something as simple as walking more strenuous than it is at sea level.
"Your respiratory system will work harder and you have to be careful to not get dehydrated," said Stevens. "I make a couple of trips per year to the west to ski. Because the air is so dry typically in Colorado, the moisture in your body gets sucked out and you need to remain hydrated. You'll see guys drinking a lot of water. At altitude with lower relative humidity, the moisture will be pulled out of your body faster than at sea level. Drink lots of fluids."
Stevens, known nationally as "The Skiing Weatherman," is an accomplished golfer in his own right, having appeared in a U.S. Amateur and three British Amateurs, while also having spent five years caddying for World Golf Hall of Fame member and two-time PGA Champion Larry Nelson. He said playing at altitude makes club selection very interesting.
"What happens at altitude is there are fewer molecules in the way, which decreases the friction you find at sea level, which is why the ball flies further -- that's a fact," Stevens said. "At a mile high, you want to make an adjustment of 7-10 percent. Headwinds and tailwinds don't have as much effect at altitude, which means there are fewer molecules to resist or boost the ball."
Steve Aoyama, Principal Scientist of Golf Ball Research and Development for the Acushnet Company, makers of Titleist golf balls, said that there are various explanations through the years as to why the ball flies further at higher elevations, but the two most prominent, he said, are usually related to thin air or reduced gravity.
"The notion of reduced gravity at higher elevations is technically true, because the strength of gravity decreases with increased distance from the center of the Earth," Aoyama explained. "When playing golf in Denver, for example, we are about a mile farther from the center of the Earth than we are when playing in Los Angeles. However, that results in only a tiny reduction in gravity. Even on the top of Mount Everest the gravity is only reduced by about one-quarter of one percent. There are greater variations (around one-half percent) due to factors such as latitude or local variations in the Earth's makeup, and nobody worries about that.
"Air density, on the other hand, can make a difference that is worth consideration," Aoyama added. "At higher elevations, the air is less dense ("thinner"). A golf ball -- or an airplane, or a car, or anything else for that matter -- has an easier time pushing through it. Thus, it doesn't slow down as quickly as it flies, resulting in greater distance. Since golf shots vary widely in their launch conditions -- the initial speed, spin rate, and launch angle of the ball -- the effect will vary greatly depending on the golfer and what club is being used."
Often much is made of the contrasting club selection of players playing at altitude compared to those at sea level. Stevens said it's important for the caddies at this week's Senior PGA Championship to be, "acutely aware and good at math."
Stevens figures, and his past experiences caddying at altitude speak to it, players should assume their ball will travel between 7-10 percent further than it does at sea level.
Aoyama, meanwhile, scientifically surmises there is actually a 5-6 percent difference in club selection.
"As a starting point," Aoyama said, "one can estimate the percentage distance increase (compared to sea level) by multiplying the elevation (in feet) by .00116. For example, at 5,000 feet elevation the increase is about 5,000 times .00116, which equals 5.8 percent. Thus, a golfer who drives the ball 250 yards in L.A. might see an increase of 14.5 yards (5.8 percent of 250) when playing in Denver. The percent increase will be less for players with lower swing speeds and/or when hitting a shorter shot. But on a mid to long approach shot, that could still make a one club difference. Not to mention that you'll be about a club closer to the green as a result of the longer drive."
Now that we know about the effects of walking and club selection at altitude, what about the spin generated on the ball? Does that become a factor too?
"It is sometimes said that the ball spins less at higher elevations," Aoyama said. "This is absolutely false."
The reason it's untrue that a ball spins less at higher elevations, Aoyama said, is because the amount of spin generated on a given shot is the result of a complicated physical interaction among the club's properties, the ball's properties and the golfer's swing properties.
"These aren't going to be directly affected by elevation," Aoyama said. "On the other hand, it's easy to see why many golfers believe that the ball spins less. Since the air is less dense, the spin has less effect on the ball's flight. The ball's spin generates a lifting force (like the wings of an airplane) as it moves through the air. The thinner the air, the smaller the lifting force. Thus, at higher elevations the trajectory is less influenced by lift, and thus has a 'flatter' shape and a more glancing impact with the ground. This produces extra roll, which contributes to the increased distance but also makes it harder to hold the green, even though the spin is the same."
As if all that wasn't enough for the competitors to think about, Aoyama noted one last thing they'll need to take into consideration.
"Everything we talked about becomes less important as shots get shorter," Aoyama said. "The shorter the shot, the slower it's moving through the air, and the less effect is felt from anything aerodynamic. Thus, on short approaches and especially on greenside shots, elevation is not something to worry about."