Last season, Chip Kelly's Philadelphia Eagles were the first NFL team to break from a traditional NFL weekly practice schedule.
This year, Mike McCarthy's Green Bay Packers will be the second.
McCarthy and his strength and conditioning coaching staff, led by Mark Lovat, already had looked at injury and GPS tracking data, and adjusted the Packers' daily practice routine in the offseason to reduce injuries.
Now starting this week, they're implementing a radical change to their weekly practice regimen to maximize player performance on game day. In its simplest terms, they're flip-flopping the last two days of the week.
The light jog-through they used to do the day before a game now will be two days before the game, which most regular-season weeks will be Friday. And the day before the game, usually Saturday, now will be a short but full-speed practice.
"I'd like to think the training of our football team has worked over the years," McCarthy said Wednesday when asked about the change. "And we have made adjustments. But how we've handled the end of the week going into a football (game), we have stayed consistent with throughout, and this is the change. It's really the last 48 hours of how you go into a game."
McCarthy is using the new schedule for preseason games, starting this week. With the game at Tennessee on Saturday, he's giving the players the day off from practice todayon Thursday. Instead, they'll do a jog-through at the new CRIC facility located adjacent the locker room, attend meetings and rehabilitate injuries.
On Friday, they'll have a short but brisk practice to get ready for the gameSaturday. The rest of the preseason will be the same, adjusted for games that will be played on a Saturday (Aug. 16 at St. Louis), a Friday (Aug. 22 against Oakland) and a Thursday (Aug. 28 against Kansas City).
McCarthy was cryptic when asked why he and Lovat made the change.
"It's more to do with the (players') neurological clock, the path that we're changing going into the game," he said.
Said cornerback Tramon Williams: "I guess it gets your muscles reacting quicker when you're doing something (full speed) the day before the game."
In other words, data from GPS tracking technology of athletes and other sources suggests that jog-throughs the day before the game have a slight de-training effect. They teach the body to move slowly, not explosively, in the final rehearsal before a game.
"(With the Packers' change), you are practicing at high intensity during a period when you need to be playing at high intensity — around match time — potentially maximizing 'transfer,'" said Tim Gabbett, an associate professor of exercise science at Australian Catholic University in Brisbane and a worldwide consultant in GPS tracking technology for athletes, including with the Jacksonville Jaguars.
Jarrett Bush, a core special teams player and backup cornerback, said the new schedule reminds him of when he was a hurdler in college at Utah State. He said that on the day before a meet, his coach put him through a short, full-speed practice of a segment of his race — usually getting out of the starting blocks and going over the first few hurdles.
"You'd only do it maybe once or twice, just like a shake out," Bush said. "And when it comes to game day — meet day — you're ready to go. You're more in tune with your body, there's a little more muscle memory than having a day off."
The Eagles used a similar regimen last year that Kelly designed with his sports science coordinator, Shaun Huls, who formerly trained special forces for the U.S. Navy. Kelly's schedule, which appears to have broken new ground in the NFL, is slightly different than McCarthy's, but the philosophy is the same.
Kelly gives his players the day off Monday, then has them practice Tuesday, which is the standard day off for the rest of the league. The Eagles also practice Wednesday and Thursday, do a jog-through Friday, and have a short, brisk practice Saturday.
In December of last season, veteran linebacker DeMeco Ryans told The Morning Call newspaper in Pennsylvania: "A lot of time, at this point in the season, a lot of guys are just hanging on, trying to push through some things. But I actually feel good, the best I've felt at this point in the season. It has to be Coach Kelly and his program. I have to give credit to that."
McCarthy still will give his players Tuesday off. But the key is the Friday-Saturday change, and that Saturday's practice, though full speed, is brief.
"You don't want to tire out the players," Bush said. "Just quick, snappy, to the point, get out."
McCarthy said this change has been in the works for a couple of years.
He and Lovat have been working with the GPS tracking of players for three years now, so they have their own data on training loads and possible effects on performance.
There's also a fast-growing pool of studies in sports worldwide, and consultants to assist in interpreting the data, that's helping teams be more scientific about training. The Packers already used the data this year to change their daily practice routine in an attempt to reduce their high injury count from the last few years.
Most notably, they've moved some jog-through and ball-handling drills from the start of practice to the end. The theory is players will be less susceptible to muscle-fatigue injures (hamstring strains and the like) because they're doing all their full-speed work earlier in practice, when they're fresher.
They probably will need a few years to conclude how well its working, but early signs are promising. Last year in their 10th practice, the Packers had 15 players sit out, including five who arrived at camp injured. On Wednesday, their 10th practice of camp this year, they had eight players out, including two who were injured coming into camp.
The players have noticed the difference, and it's probably opened their minds to the new weekly routine.
"Here they're all about finding out new ways to do things, better ways to recover, things like that," Williams said of the Friday-Saturday change. "I like it. If players come to them, 'I don't feel it's helping, we don't like it,' I'm pretty sure we could change it at some point. But I like the direction we're going with this. Interested to see how it will work."
— firstname.lastname@example.org and follow him on Twitter @PeteDougherty.