During a losing season, tensions run high both inside organizations and out. During the Dallas Cowboys’ 6-10 campaign, things were no different. In early October, they were 1-3 and had almost given up a 50-burger to the Cleveland Browns. When asked about their effort on defense, safety Xavier Woods probably applied a little too much candor:
The relationship between Woods and Cowboys fans never recovered as the team continued to falter. Dallas let him walk, opting instead for Damontae Kazee — with Jayron Kearse filling in while Kazee gets healthy. Now, Woods has signed a one-year, $1.75 million contract with the Minnesota Vikings. He will be the de facto starting safety — draft miracles notwithstanding — and that effort problem is now our problem.
Should we be concerned?
The optics on that quote are not encouraging, but Woods does have a point. Players don’t take it easy on some plays because of laziness; it’s a point of strategy. After accounting for stoppages and downtime, there are about 11 minutes of full-speed gameplay in a typical NFL game. For cornerbacks and receivers, that means about 1.25 miles of total distance covered. Over 70 plays, that averages to about 31 yards covered per play. Safeties run a little less, but the idea remains.
Even the most honed and conditioned athletes will lose a step by play 65 or 66 if they sprint all 31 yards on each play. It stands to reason that a player would slow down as the game wears on. Big Data Bowl contestants Cathy Ha and Lucas Calestini investigated this in 2014 but found the opposite. Depending on position, players don’t slow down that much over the course of a game.
Players likely don’t want to play at their slowest during the fourth quarter, when stakes are highest. So conserving energy for that moment is paramount. The above graph suggests that players are pretty good at conserving energy throughout a game. At safety specifically, there is ample opportunity to find some rest without jeopardizing your teammates or the result of a play.
Here’s every snap from the first quarter of Minnesota’s 2017 shutout at Lambeau Field, focused in on Harrison Smith. This game won him NFC Defensive Player of the Week honors, but watch how often he plays at a light jog.
It may help to examine what happens in our bodies when we get winded. Our bodies have a way of making energy out of oxygen, fat and other important fuels. That energy comes in the form of cells called Adenosine Triphosphate (you can call it ATP). Think of them as little fuel cells or little bombs in your body. Those little bombs travel to the muscles, the muscles split them apart, and they explode with molecular energy. That energy turns into the actual motion of your muscles.
Your body is making ATP all the time. It stores that ATP in your muscles to use whenever it comes up. When you exercise and use up all that ATP, it kicks into high gear and makes more. Keep that pace up, and it turns into practice for your body’s ATP-making cells. That’s why lifting weights gets easier if you lift regularly (in addition to muscle growth, which is a whole other can of worms).
When your muscles begin to run out of ATP, things start to release acidic compounds. That’s called “acidosis” and it’s why your muscles feel like they’re burning when you work out harder than usual. Your body releases lactate to calm it down, not unlike drinking milk to soothe your mouth after too many hot wings (as an aside, that lactate hardens up later which is what makes you sore the next morning). As you train harder and harder, your body learns to use that lactate to make yet more energy (which is why you get less sore as you keep with it).
You don’t necessarily want to achieve acidosis all the time. You want to train those ATP-making cells by keeping them in high gear for as long as you can before your body goes into acid mode. That’s why trainers will recommend a responsible pace when working out. If you want to prepare for a long marathon, try running a little slower during your training. If your body is out of oxygen, it can’t practice making ATP as efficiently. If you sprint until you crumple over gasping for air, you ultimately won’t optimize your system.
When you lift weights, trainers recommend that you lift in sets and take breaks in between those sets. ATP gets used up pretty quickly and has to replenish. A well-trained body — like an NFL athlete’s — can replenish that ATP but needs a bunch of oxygen to do so. Hence, “catching your breath.”
You don’t necessarily need to know all that to understand that a player won’t want to be winded as they head into a key play. So if the opportunity presents itself to lightly jog and stay alert, players should take advantage. It’s not a lazy way to play, it’s a strategic one. The key skill is choosing the correct plays. You’ll notice that Smith won’t sprint across the field to chase down a toss to the other sideline. That’d be a fruitless waste of energy. However, he will play hard in coverage or in his run fits.
When Woods talked about effort, it sounded like there were some legitimate issues in Dallas. Mike Nolan was fired after the end of the season, which is no coincidence. That defense struggled. But Woods is right when he says it’s impossible to go 100 percent for all 70 plays. Maybe it should remain unsaid, but with a little understanding of how the human body works, we can also understand why players need to jump on opportunities to restock their ATP stores.