PHILADELPHIA -- Chip Kelly is nearly as well-known for his commitment to sports science as he is for drawing up innovative plays. But even the Philadelphia Eagles' head coach has his limits.
“In terms of us being able to construct a hyperbaric chamber over that football field,” Kelly said, gesturing toward the NovaCare Complex fields, “we can't do that. We're at the same advantage or disadvantage of anybody else going in there.”
There, of course, is Denver’s Sports Authority Field at Mile High, a stadium whose very name tells the tale. Denver’s perch in the Rocky Mountains, in the thin air a mile above sea level, creates a problem for any visiting team in football, basketball or hockey.
The question is what kind of problem: physical or psychological? The issue is more than academic for an Eagles team determined to run an uptempo, no-huddle offense regardless of the elements.
“A lot of it is more mental than physical,” Kelly said. If he believed otherwise, you can imagine a work crew hammering away at that hyperbaric chamber in South Philadelphia. “Football is an anaerobic sport. We’re not going there to run a marathon.”
Rob Connolly is a sports scientist, too. An exercise physiologist and coach with USA Cycling, Connolly runs Dogma Athletica, a high-altitude training center in Vail, Colo. Connolly has been intrigued by what Kelly is trying to do on the football field, using pace to put stress on his opponent.
According to Connolly, the effect for the Eagles on Sunday will be both physical and psychological.
“It will come more into play with the type of tempo both teams want to run,” Connolly said. “Football is anaerobic, but that makes it tougher. You’re working in a short anaerobic burst and then trying to recover quickly is tougher. You’re only getting 85 percent of the oxygen you would take in at home.”
Simply put, there is less oxygen in the air you breathe at higher altitudes. The body has to work harder to get the oxygen it needs. For athletes, that can mean tiring faster. Many world-class athletes train at altitude for this very reason. To acclimate, the body eventually produces more red blood cells, and that can be an advantage when the athlete comes down from the mountain to compete at lower elevations.
Connolly said athletes who aren’t acclimated -- a process that can take more than two weeks -- will find their respiratory rates going up 5 to 8 percent.
“There’s a psychological effect there,” Connolly said. “Any time you notice your breath, it can be disconcerting. You’re panting. Your mind is not on whatever else you’re doing. You can lose focus, and it can affect your motor skills.”
Eagles center Jason Kelce said the team normally practices fast enough to create fatigue in the players. That prepares them for maintaining focus when they tire in games.
“It’s more overhyped than the reality,” Kelce said of the altitude issue. “I’ve heard a lot of guys say that it almost feels like you’re just playing on a humid day. It has the same effect where it’s harder to breathe. Most guys who have played there say that it doesn’t make that big of a difference. You might notice it in warm-ups, but once you get the game going, things are going by too quickly to take notice of that.”
Eagles outside linebacker Connor Barwin played in Denver last year as a member of the Houston Texans.
“I didn’t notice it at all,” Barwin said. “I think that’s just something they say. Football is four- to six-second plays. We’re not running a marathon. So it’s something I didn’t notice at all.”
“I think it’s a combination,” Williams said. “It’s a lot mental, but I think it’s a lot physical as well. It’s a change. Your body’s not used to it. You’ve got to be mentally tough to overcome it.”
Eagles outside linebacker Trent Cole shrugged it off. You get tired in football games at any altitude, he said.
“If you get tired,” Cole said, “come out of the game. There’s nothing to it. It’s how you take it and what you can withstand.”
Connolly is a fan of Kelly’s overall approach and thinks it will be very effective over time.
“I think you’ll see some copycat stuff,” Connolly said. “Good players on offense and defense decipher what the other team is doing and anticipate the play. By going so fast, Kelly makes it harder to do that. Combine that with fatigue, and he’s on to something. It’d definitely fun to watch.”
But there is a definite challenge trying to push the tempo at altitude. Kelly said his Oregon teams had no trouble when they played in Boulder.
“It wasn’t a big deal,” he said. “You play against the Broncos, it’s a big deal.”
In other words, Peyton Manning and the Broncos have to be the focus. There isn’t much that can be done about the altitude.
“I understand his approach,” Connolly said. “It’s a good mindset, just coming in and doing what they do and not making too big a deal out of it. If I were him, I’d have guys on the sideline like hockey players, ready to change on the fly.”
That might be tough. The truth is, the Eagles would have a difficult time playing this team anywhere, at any time. They prepared all week for that challenge. All they can do about the altitude is find out for themselves.
“Afterward,” Kelce said, “if it affected us, I’ll let you know.”