SAN ANTONIO — Eighteen men played in Game 1 of the NBA Finals. Nine played 30 minutes or more under stifling heat and humidity.
Only one crumpled to the court because of severe muscle cramps.
That the debilitated player happened to be the Miami Heat's LeBron James only made the matter more puzzling: If the heat had little effect on everyone else, why was it so damaging to James, one of the greatest athletes on Earth?
There are no easy explanations, but there is this physiological fact: Some people are simply more susceptible to cramping than others.
"There are definitely, quote-unquote, 'crampers,'" said Dr. Marci Goolsby, a sports medicine physician at New York's Hospital for Special Surgery. "Not that I know if LeBron is one of those people. ... It is a bit of a puzzle sometimes to try to figure it out. It's just some people may be more susceptible."
By his own accounting, James seems to qualify as a cramper. On Friday, James told reporters that he dealt with cramping "a lot" during his high school career, even undergoing a battery of tests at the time. James was also hampered by leg cramps in Game 4 of the 2012 Finals and has dealt with the problem periodically throughout his NBA career.
Yet even with that history and a general knowledge of how to avoid the problem (primarily, by keeping hydrated), James fell victim to cramping again Thursday night when his left leg seized up in the fourth quarter, forcing him out of the game.
It quite possibly cost the Heat the win.
A variety of factors were likely in play Thursday night, starting with the punishing heat inside the AT&T Center. Because of a broken air conditioning system, the temperature climbed past 90 degrees with stifling humidity.
The malfunction apparently occurred just before the game, and it was not until halftime that it became clear the problem would not be fixed. So James and the Heat's medical staff could not have anticipated, nor prepared for, the sweltering atmosphere.
Cramping is generally caused by muscle fatigue, and the unusual heat "can make the muscles more fatigued," said Goolsby.
"You may sweat more," she said. "And some people are saltier sweaters than others. ... People who are high salty sweaters lose a lot of salt, and that's electrolytes, and those people might be more susceptible to cramps."
So, if James is indeed a cramper and a saltier sweater, he would be much more vulnerable under adverse conditions—like, say, a 90-degree arena.
"There may have been a perfect storm of circumstances that made it happen the other night," said Goolsby, who works as a consulting physician to the WNBA's New York Liberty.
"Unfortunately, once it starts, it can be really hard to try to get rid of," she said. "You can try to get their fluids up. You can try to hydrate them quickly. But sometimes, once the muscle cramps, it's hard to get rid of. And it's incredibly painful."
Trainers can try to work out a cramp—as the Heat's staff did with James on the bench Thursday night—"but you mostly just have to wait for it to pass," Goolsby said. "And then the muscle is tight afterward, and it doesn't take much to get it to cramp again."
That brings us to the other vexing question: Since James knows he is susceptible to cramping, couldn't he have anticipated the problem and prevented it by loading up on electrolytes and hydrating before the game?
"You could do everything right and still have things happen," Goolsby said.
She added, "Sometimes we can identify issues, and sometimes we can't. ... Let's say he had a lot of cramping and then somebody said, 'You should take more salt in during the day of games.' And maybe that helped him. But for some people, it doesn't. It's really sometimes a challenging thing, and it's hard for people who are crampers. Clearly, he's gotten over it because it's not happening on a regular basis."
The Heat, like most NBA teams, employ a small army of physicians and trainers, including James' longtime personal trainer, Mike Mancias. James also has a personal chef who helps manage his nutritional intake. Cramping can partially be managed through diet.
Had the teams known they would be playing in 90-degree heat with high humidity, James might have been advised to increase his fluids and electrolytes during the day. But of course, there was no way of knowing any of that.
One final point: Once a muscle cramps, it becomes nearly impossible to use it. James could barely stand Thursday night. Yet some fans and pundits insisted he should have somehow kept playing.
"You really can't," said Goolsby. "You can't push off. It's like a rock. ... You just can't even engage that muscle, to do what it needs to do."
Howard Beck covers the NBA for Bleacher Report. Follow him on Twitter, @HowardBeck.
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