A stopwatch is certainly one tool for measuring the speed of NFL players, but like a lot of tools that have been around for a while it is probably no longer the best one to use.

Simply gauging how long it takes a player to go from point A to point B in a straight line is a convenient way to compare a lot of people in a similar situation, but it's not a thing that really happens on the football field much.

A good example: Vikings rookie running back Dalvin Cook. At Florida State, Cook gained a reputation as one of the quickest players in college football. Then he arrived at the NFL scouting combine and ran the 40-yard dash in 4.49 seconds — a good time, to be sure, but maybe not the number some teams were looking for.

SB Nation wrote of Cook's combine performance: "An average performance at the 2017 NFL combine tempered a lot of enthusiasm. Cook ran a 4.49-second 40-yard dash, slower than expected."

His 40 time was a subject of discussion again when he ran twice at his pro day — once in the mid-4.4s and once in the low 4.5 range. While NFL.com analyst Lance Zierlein said, "His 40 time at the combine was more than fast enough," it was still noted that Cook's overall combine workout, including his dash time, was "less than stellar."

The Vikings drafted Cook in the second round. Presumably character questions were as big a factor as anything in him lasting that long, but teams could also nitpick about his speed.

Dalvin Cook posted a disappointing 4.49 time in the 40 during the NFL combine, slower than many scouts expected.

So it was interesting — and heartening, for a Vikings fan — to see this nugget tweeted Tuesday by Randall Liu of NFL Communications:

"Dalvin Cook recorded 2 of the top 3 fastest max speeds by a RB in Week 1 reaching top speeds of: 20.45 MPH 19.98 MPH."

That jibes with a tweet from April — between the combine and the draft — from Bleacher Report's Marcus Mosher: "According to Sports Science, Cook has the second-fastest top speed of any RB they've tested in the past five years."

So even if Cook is decent (but not great) in the 40, he achieves a max speed that is elite. To me — and perhaps certain NFL teams, including the Vikings — that is a much more relevant number. It speaks to his burst and high-end speed, which are critical in gaining separation, turning a corner and other things that happen on a football field.

These top speeds can be tracked with GPS devices. It's one of the stats the NFL is touting on its sub-site nextgenstats.nfl.com. Among running backs, only Chiefs rookie Kareem Hunt was faster than Cook in Week 1.

The Week 1 list isn't a definitive look at the fastest running backs since it stands to reason that a rusher needs to find some open space to reach a high speed. Cook had two runs of 30-plus yards in the fourth quarter, and those accounted for those elite speeds. Hunt's top speed was achieved on a 58-yard run.

Still, it speaks to Cook's acceleration. Those results — with pads on, carrying the ball — mean a lot more than anything you will glean from a 40-yard sprint with no pads and no ball.