It has been proved time and again that football is, as Vince Lombardi said, a game of inches. Teams win or lose based on the smallest of distances. A deep pass glances off a receiver’s fingertips. One or two links of a chain force a team to punt instead of keeping the ball.

But football is also a game of speed. And the measurement of that speed can help explain why a deep pass was not caught. Or why a running back was tackled two chain links short of a first down.

Thanks to computer chips inserted into NFL players’ shoulder pads, we can measure and analyze the speed at which the game is played. The data, provided here by Sportradar, is used by teams to help make personnel decisions, scout opponents and even call plays. It also helps separate players who have “game speed” from those who merely run fast at the NFL combine.

“Combine speed is overrated,” Los Angeles Rams receiver Tavon Austin said. “It might give you a good look to see what you can run in a straight line, but football’s not played in a straight line.”

Who is the fastest from scrimmage?

At the 2017 combine, 53 players ran the 40-yard dash faster than Louisiana State’s Leonard Fournette (4.51 seconds). Ten running backs were faster, and wide receiver John Ross set the combine record at 4.22.

But it is Fournette, the 240-pound bruiser, who has actually clocked the NFL’s fastest speed on offense this season, according to Sportradar.

Against the Pittsburgh Steelers in Week 5, Fournette, the Jacksonville Jaguars’ first-round pick, showed why game speed is more important than combine speed.

With the Steelers stacking the right side of the line of scrimmage, Fournette found a hole on the left side and broke through to the open field. From there, it was a foot race against Steelers safety Sean Davis (4.46 in the 40), who was closing fast from the right side.

But Fournette found an extra gear, reaching a top speed of 22.05 mph to pull away and score a 90-yard touchdown. (For comparison, Usain Bolt hit 27.8 mph when he broke the world record in the 100-meter dash at the 2009 world championships. He was not wearing football gear, of course, or running on grass.)

Davis topped out at 21.06 mph in pursuit.

Fournette, who said he had never been caught from behind in the open field, believes combine time is not a fair indication of a player’s true speed.

“I was 240 and ran a 4.51,” Fournette said, referring to his weight. “There’s guys who ran 4.4s or whatever else and they’re getting caught from behind in a game. Football speed and track speed is a big difference, man.”

Other top speeds on offense: Todd Gurley, Rams (21.98 mph); Fournette, again (21.76); Marquise Goodwin, 49ers (21.68); and Tyreek Hill, Chiefs (21.64).

On defense, the thrill of the chase

In Week 11 against the Dallas Cowboys, the Philadelphia Eagles’ newly acquired running back Jay Ajayi broke free on a run (similar to that of Jacksonville’s Leonard Fournette’s), with nothing but open field ahead of him. Ajayi, who reached a top speed of 20.41 mph on the play, was caught by Cowboys safety Byron Jones, who ran 22.11 mph in pursuit, according to Sportradar.

Many players agree that the thrill of the chase provides an extra boost. Might a running back move just a little bit faster knowing that 11 men were trying to smash him to the ground?

“Oh, absolutely,” said the New York Jets’ Elijah McGuire, who had the fourth-fastest speed for a running back this season (21.17 mph) “When people are chasing me, I think of it as a dog is behind me. So I don’t want to get caught.”

Other top speeds on defense: Malcolm Butler, Patriots (22.07); Johnson Bademosi, Patriots (21.72); Devin McCourty, Patriots (21.66); and David Amerson, Raiders (21.62).

Even linemen are fast

The majority of NFL players are fast — really fast. So the top speed of the fastest running back is only slightly better than the top speed of the fastest defensive lineman. If the fastest players at each position were able to race 100 yards at their top recorded speed, here’s how they would finish, according to Sportradar.

Seattle Seahawks quarterback Russell Wilson’s top speed of 20.14 mph is slightly faster than Cam Newton’s 20.08. But in a twist, Wilson reached that speed playing some defense — chasing down Rams safety John Johnson III after an interception to save a touchdown. After the game, Wilson said the tackle “took me back to my high school days when I used to play corner.”

Likewise, Browns receiver Ricardo Louis hit 21.88 mph chasing Houston’s Johnathan Joseph after an interception in Week 6. Louis did not have enough room to catch Joseph, who scored on the play.

Which team has the fastest receiving corps?

Raiders owner Al Davis was obsessed with speed. Davis made it his mission to draft or trade for as many fast wide receivers as possible, including Cliff Branch; Raghib Ismail, who was known as Rocket; Willie Gault; Darrius Heyward-Bey; and Jacoby Ford.

Davis, who died in 2011, would probably hate this season’s Raiders. Oakland has the second slowest receiving group in the NFL, according to Sportradar. If we look at every pass play in the NFL this season through Week 16, and then average the top speed of each receiver across all of those plays, the Rams have the fastest group with an average speed of 13.32 mph. The Raiders, at 11.96, are slower than every other team except the Packers, who are more than a1.5 mph slower than the Rams at 11.74 mph.

The 60-yard foot race

Quite often, a team’s fastest player is the “gunner” on special teams. A gunner’s job on punt and kickoff coverage is to run down the sideline very quickly in an effort to tackle the returner (while eluding the opposing team’s gunner). Many of the top speeds on special teams this season were negated by penalties, but the Houston Texans’ Chris Thompson (22.64 mph) and the Atlanta Falcons’ Marvin Hall (22.47) were the fastest.