The 300-yard shuffle runs await the Tennessee Titans upon their return from summer vacation, which starts today and runs until they report for training camp on July 25.
To prove their fitness, players will have to run.
They'll go 25 yards there, 25 yards back and do it a total of six times. After a three-minute rest period, they'll do it again. Then another three minutes and a third set.
John Glennon of The Tennessean outlines some of the details and player reaction here.
"I did it when I was a player, and I always had a pit in my stomach just before I did it because it's a tough test," coach Ken Whisenhunt said. "I know there's many times when I was hot during the summer while working out, but I thought I'd have to do a little extra because of the [300-yard shuttle run]. I think that's an important thing."
Players run in groups: wide receivers and defensive backs together; running backs, tight ends and linebackers; linemen from both sides of the ball.
Each group has a set time, and players must finish each shuttle run under that mark.
Somewhat remarkably to me, I couldn't find one player who knew definitively what that time was.
Dexter McCluster is a running back now, but said he'd run with the receivers. He said the expected finish time is 56 seconds, and he was the most definitive of at least half-dozen players I asked about it.
Most said they didn't know and aren't particularly concerned.
"I don't care," tight end Delanie Walker said. "Whatever they give me, I'm going to make it."
"I'll come back in tip-top shape," rookie running back Bishop Sankey said. "And I'll be able to kill it."
Mike Munchak favored 110-yard gassers without all the stopping and starting, so this will be an adjustment back to what the team did at least some times under Jeff Fisher.
"Run fast enough back and forth; fast enough not to get in trouble," Lewan said of his plan.
Warmack would have the highest odds of having the most trouble with the test.
Some guys will practice shuttles to be sure to be ready for the specific test.
Cornerback Blidi Wreh-Wilson said a few times a week when he's tired after lifting and working out, he will run shuttles. Friends will time him to keep him abreast of how he's doing.
"It's difficult," Wreh-Wilson said. "After the first one you start to feel the lactic acid building up, you can feel it in your legs."
"I just make sure I'm comfortable with the times and the transitions of the 300-yard shuttle."