EDEN PRAIRIE — The Minnesota Vikings clearly have the energy, excitement and enthusiasm of a team with a new coaching staff.

Springtime is when optimism levels are highest, particularly in the NFL, and the freshness that comes from change only heightens this feeling.

The Vikings have begun their offseason strength and conditioning program, allowing them extensive interaction with coach Mike Zimmer and his staff for the first time.

“My first impressions of everybody have been great,” tight end Kyle Rudolph said Tuesday. “From the top down, all the new football coaches, but also the new strength coaches as well. It’s definitely a different system, but I think the change is good so far.”

The only results that matter are months away, of course.

For now, though, the Vikings have been buzzing about the beginning of Zimmer’s period of influence. His predecessor, Leslie Frazier, was popular with the players, too.

The praise for the new boss is no slight to the old one. But that’s what happens in this league after a 5-10-1 finish, two years after a franchise-worst 3-13 record. The clean slate can be a major motivator.

“They’re getting their point across right away with the type of people they want on this team, type of people they want in this building and mentality we should take while we’re in this building,” linebacker Chad Greenway said. “I think once you get the point across early, you set a foundation for what you want to create during the season.”

The same type of admiration, publicly at least, was expressed for Frazier, and for Brad Childress, and for Mike Tice and so on before them. Sometimes the praise can border on platitudes.

Rare is the player who will be willing to speak out in the NFL and share concern about a new regime, given how quickly and easily many can be replaced.

But Zimmer’s down-to-earth style has obviously made a strong impression so far. His intensity and passion have stood out, in brief get-to-know-you conversations or more-extended meetings.

“He loves the game of football. Guys, that’s the bottom line. He loves the game. He loves coaching. He loves being around players, and he wants to make each and every player better,” defensive end Everson Griffen said.

New cornerback Captain Munnerlyn did his research on Zimmer prior to signing with the Vikings.

“Every player he coached in the past that I’ve talked to had great things to say about him,” Munnerlyn said. “He’s a defensive-minded coach. He’s going to work you. That’s why I came here. I want to work. I want to win.”

Now that the formal workouts have started at Winter Park, with minicamps and organized team activities on the field coming soon, the initiation process has been ramped up.

One tangible change has been in the style of strength training, a shift from machine work back to more-basic free weights.

The sessions are voluntary, according to the collective bargaining agreement, but coaches strongly urge all players to participate. One notable absence so far has been running back Adrian Peterson, who has often split his offseason training time between Minnesota and his native Texas.

“I thought they came in in shape. I think guys were excited about the changes,” strength and conditioning coach Evan Marcus said. “When a new staff comes in there’s always a certain level of excitement, so they want to prove themselves.”

NOTES: The Vikings signed TE Allen Reisner, returning a player who was here in 2011 and 2012 to the roster. He spent last season with Jacksonville. … The Vikings also claimed LB Terrell Manning off waivers from San Diego. He was drafted by Green Bay in 2012 in the fifth round. … Munnerlyn said he has a nickname for himself: “The Big Difference.” … Rudolph, who has entered the final year of his rookie contract, said he has not been approached about an extension. … OL Josh Samuda badly hurt his right ankle during a conditioning drill gone awry that was open to reporters.