Heat, Humidity Knock Out More Players at U.S. Open Than Federer, Murray

Before he was forced to retire due to the effects of high heat and humidity, Jack Sock hits a forehand against Ruben Bemelmans of Belgium at the 2015 U.S. Open tennis tournament in New York on September 3. Geoff Burke-USA TODAY Sports

On Thursday, Jack Sock became another casualty of the heat and humidity at the U.S. Open. The American collapsed on court during the fourth set of his second round match, and was not even able to lift his arm to shake the hand of his opponent, Belgium's Ruben Bemelmans. Hours later, Denis Isotomin of Uzbekistan had to retire due to an injury sustained during his match against Austra's Dominic Thiem.

As of Sunday, the number of players who have had to retire from the tournament due to injury was at 16, with 12 of those coming during the first round. This broke the previous record of nine, set during the 2011 U.S. Open. Above-average temperatures and high humidity are largely to blame, and while not all the injuries were directly heat-related, it certainly exacerbated underlying problems.

The temperatures were consistently in the 90s during the first four days of the tournament, but that doesn't come close the record-setting temperatures at last year's Australian Open, where it got as hot as 43 degrees Celsius, or a whopping 110 Fahrenheit. While the heat caused Canadian player Frank Dancevic and a ball boy to collapse on court and China's Peng Shuai to suffer vomiting and cramps, there were still far fewer retirements than we're seeing at the current U.S. Open. However, Melbourne has a relatively dry climate compared to New York, where humidity is more to blame. The dew point, rather than air temperature, gives a more accurate reading of how players will feel since it measures how well sweat will evaporate from the skin and cool the body, and it tends to be at least 10 degrees higher in New York than in Melbourne.

There is a heat rule for women players, which went into effect Thursday at 1 p.m. It allows them 10 minutes' rest between the second and third sets. But no such rule exists for the men, which could be why 14 of the 16 retired players have been male. Andy Murray, who criticized the handling of the extreme heat at the 2014 Australian Open, is in favor of men getting the same break as women do, especially considering the men have to play a best of five sets while the women take on a best of three. "You know, we don't have the luxury of having the 10-minute breaks, set breaks, when it's extremely hot and humid out there." Murray said. "I think, yeah, I mean, when it's extremely hot and humid, it helps to have that break. I don't know exactly what it's for. But I guess you get the chance to sort of go off and change, get under a cold shower if you want to."

Other players, though, feel that it's an athlete's responsibility to prepare for any kind of extreme weather. "I'm surprised to hear that players are retiring because of heat. I mean, if you're injured, it's different and all that. But I'm sure from the 12 or 13 players that have retired, I'm sure there's involvement with heat," Roger Federer commented in his postgame interview Thursday. "What I don't understand, if that's the case, we've been here in North America for some time. It's not like, all of a sudden, hot. I mean, it was more on the warmer side, but it's not like impossible, to be quite honest. Really no excuse for that."

While players may be at odds over the right way to address the heat, it's clear that something will need to be done in the future. This past July, Wimbledon faced record temperatures as players competed during the hottest month on record. September temperatures continue to be well above average in New York, and it's highly possible 2015 will set a new record for warmest year yet. Jack Sock may have been an extreme case of what the heat can do to a player, but it proves the weather must be taken into account well before hitting the court.