Joe McKnight, and the physics behind a blocked punt

FLORHAM PARK, N.J. — It was the changing moment of the Jets dramatic 27-24 comeback win over the Cowboys on Sunday night as, with five minutes left in the game, Joe McKnight dove full body to get his hand on Mat McBriar's punt. Isaiah Trufant, who was on the Jets practice squad just two days earlier, collected the bouncing ball and ran in for an 18-yard touchdown to make it a 24-24 game.

For the Jets, he was McKnight in shining armor, but from a scientific point of view, it was an incredible athletic feat.

The physics behind this play proves the difficulty of the challenge for McKnight, who ran unmolested through the heart of the Cowboys line and managed to stop on a dime, in harnessing his 5-11 frame in extending his body to get his hand on the ball. And McKnight, a former star running back at USC and the Jets' fourth-round pick last year, managed to do all this at full speed without making contact with the punter, which would have been a likely penalty.

"McKnight never stopped. He started at about the 42-yard line and began a dive forward at about the 37-yard line. He covered that 5 yards in about 1.25 seconds, giving an average speed of 4 yards per second. If his acceleration was constant, that works out to about 8 mph average for the 5 yards, or about 16 mph at the 37-yard line," said Dr. John Eric Goff of Lynchburg College, who specializes in the study of sports physics and is the author of Gold Medal Physics: The Science of Sports. "This is, by the way, not McKnight's top speed, which might be closer to 20 mph."

Last spring at the NFL Combine, McKnight ran a 4.47 time in the 40-yard dash, fifth fastest among the running backs. On this play, he had a straight, unimpeded run to the punter which allowed him to pick up speed, but also made his stopping a difficult task.

"With his arms fully extended, he covers nearly 8 feet. He began his dive at the 37-yard line when the ball was at about the 30-yard line. He met the ball at the 32-yard line, meaning he covered the last 5 yards as a laid-out projectile," Goff said. "He had enough forward momentum that when he began his dive, he could cover nearly twice his total length as he shot toward the ball. The great athleticism in what he did is that he committed to diving when he was nearly 7 yards from the ball. He was able to approach the ball low so that his chances of hitting the punter were low."

With the degree of difficulty in pulling off a play like this, it is no wonder then that punt blocks are in such short supply as last year, only 12 punts were blocked in the entire league.

But for the Jets, the blocked punt proved the catalyst in a game where the offense was effective in only spurts and the defense gave up plenty of big plays, and the team is averaging one blocked punt per season since Mike Westhoff became the special teams coach in 2001. McKnight's moment of individual brilliance made kicker Nick Folk's game-winning 50-yard field goal with 27 seconds left possible.

And it might also set him up to be a bigger part of the Jets' plans, one year removed from limited playing time with the offense.

"I said 'Son, if you keep making plays like that, you're going to be a part of this offense.' That was a huge, huge play," head coach Rex Ryan said. "We all saw it. It was unbelievable."

Kristian R. Dyer can be followed at

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