By the time Doug Pederson finally had enough of the first day of contact at training camp, a nearly three-hour session in which pads cracked sharply through the swampy air, even the hundreds of selected season-ticket holders and invited guests had drifted from the sideline to the comfort of their air-conditioned cars.

It was a very long set of drills on Saturday. Not all involved hitting, but enough so that the players knew a little more about each other when it was over, and they also knew more about the head coach. This is what he said he would do, although he didn't say it would last three hours, and anyone who expected the Eagles to ease into the tackle football part of the year hadn't been paying attention.

As is usually the case, the players on defense liked the flipping of the switch more than those on offense. Hitting is what evens things up for them. When the defense must be concerned with pulling up and tapping a ballcarrier or a receiver as he jukes along, the field opens up for the offense. When they can go full gas, it's a different game. Plus, there are truths to be discovered out there.

"Let me try to put this in a good way," defensive end Vinny Curry said, searching for words that would be both accurate and publishable. "It separates the soft people."

Saturday was a very good day for the defense, and not so much for the offense. There were a lot of dropped passes in traffic, a lot of running backs who stuck a heel into the ground, and some passes that were hurried and off-target.

"It's a lot different than in just helmets and shorts," safety Malcolm Jenkins said. "You start to see that margin for error get a lot smaller, especially for the offense. It was a good start. Guys have to get more acclimated to the weather and wearing pads and focusing in when you're tired. But for the most part, I thought it was solid."

It was solid, and also a solid indication of what is to come under Pederson. If the previous three years under Chip Kelly were maddening and demanding for the players in some regards, like the incessant tempo, they were also easier in others. Kelly didn't make them hit very often and not for long when they did.

Players "buy in" to a coach's methods in exact proportion to the extent those methods are successful. The Eagles were with Kelly until they weren't, and the same will go for Pederson. He treats them like grown-ups, doesn't monitor their sleep and their daily calorie intake, but he also requires old-school sacrifice on the field. He will get it from them as long as the players feel they are being led into more than just a meat grinder.

"He stands up in front of them and talks about, 'I did it. I've been on teams that won a Super Bowl, gone to championship games,' " Howie Roseman, the executive vice president of football operations, said Saturday. " 'This is how we did it. This is a time-tested system that gets you ready to play, that gets you able to perform out there.' Him being able to say that he's gone through it brings credibility."

There wasn't any place to hide on Saturday. The team had full 11-on-11 sessions and special-team sessions, but there were also a substantial number of one-on-one drills - this receiver against that defensive back, this offensive lineman trying to block that defensive lineman. All of those were individual battles with everyone watching, and there were winners and losers. Drill by drill, hit by hit, the depth chart writes itself.

"I love the being in the pads. I love the physical part coming back to Philadelphia, which is going to be huge for this team," said former safety Brian Dawkins, who is joining the team's scouting department as part of a career development fellowship. "This first day is usually a tough one because you're knocking off that rust, getting back to playing football with pads on, which is difficult."

The Eagles are scheduled to go in pads on Sunday and Monday before a day off on Tuesday, and Pederson said he would adhere to that basic routine throughout camp, giving the team a rest from hitting every third or fourth day. The collective bargaining agreement limits contact drills, and has abolished two-a-days, but Pederson will get his share. That much is obvious.

After practice ended on Saturday, the veterans removed their helmets, along with their dripping jerseys and shoulder pads, and handed them to the rookies. Carson Wentz trudged off the field carrying the equipment of Sam Bradford and Chase Daniel. Defensive end Alex McCalister was the luggage handler for Bennie Logan and Vinny Curry.

Tradition is a great thing, and, for better or worse, putting on pads and smacking one another around is football tradition. Deciding who carries the pads back is another one.

"Today, we got to hold everybody accountable for what we're doing out there," Curry said.

It takes more than three hours to really get that accomplished, but Saturday was a start, and a loud one.