Ann Arbor — During offseason summer workouts, strength coaches across the country become the most important individuals working with college football teams.

They are authorized by NCAA rules to work with the players in the summer and become as important to the players and program as the coaching staff.

Kevin Tolbert is not new to Michigan. He was an assistant strength coach from 2001-2007 when Lloyd Carr was head coach, but after working at Stanford and the San Francisco 49ers, coach Jim Harbaugh, brought Tolbert back to Ann Arbor as director of strength and conditioning.

The Michigan players said they have grown attached to Tolbert, who was a protégé of longtime Michigan strength coach Mike Gittleson, beloved by Wolverines with whom he worked. They appreciate Tolbert’s methods of motivating and said the conditioning results are evident, as Harbaugh has pointed out several times in recent weeks, saying his players look stronger and in better shape.

“He’s a funny guy,” senior linebacker Joe Bolden said of Tolbert. “These guys, they love us, and we love them. We spend a ton of time with them. I’ve seen coach Tolbert almost every day for the last seven months. You’d think the face would get old, but it doesn’t because he’s always keeping guys on their toes, cracking a joke at the same time getting after you. He knows when work needs to get done. He has a way of doing things a little bit different than (previous strength) coach (Aaron) Wellman.

“Coach Tolbert motivates guys by loving you up, caring about you, then again, he’ll rip your butt. Coach Wellman is a very intense guy. Coach Wellman wasn’t necessarily as open, but once you suffer with him, you’re close to him. I have the utmost respect for both. Love both of them. Suffered a lot with both of them.”

Tolbert spent six years working with Harbaugh, including the last four as assistant strength and conditioning coach with the 49ers. He worked two seasons, 2009-2010, at Stanford, where he was promoted to head strength coach in 2010. Tolbert spent the 2008 season with the Lions as assistant strength coach, so he’s had five years working with NFL teams in addition to his college experience.

During Michigan’s media day last Thursday, the day before the Wolverines opened preseason camp under Harbaugh, countless players said they were in the best shape of their lives.

“I feel the best I ever have,” offensive lineman Kyle Kalis said. “I went from 18-percent body fat to 14-percent body fat this offseason. My speed’s gone up, my agility has gone up, (and) my strength. I went from 295 (pounds) last season and I’m 306 right now. I’m feeling the best I ever have, (and) mentally the best I ever have, confident, and that’s the key.”

Running back Derrick Green, who arrived two years ago 20 pounds overweight as a freshman, also said he’s in the best shape he’s been in while at Michigan.

“I’m faster, stronger, more elusive,” Green said.

Center Graham Glasgow, like Kalis, said he has dropped his body fat percentage.

“Feel great,” he said. “Body feels awesome.”

But ask any of them what exactly Tolbert has done to make such significant changes, and they have a hard time pinpointing one thing. Much of the time, how the strength coach relates to the players, particularly seeing them on an almost daily basis, is the key to how the players respond to his methods of training.

“Coach Tolbert is the best,” Glasgow said. “Coach Tolbert has made it fun to go in there every day. The mentality of the kids has changed as well. It’s not like, ‘Oh my gosh, I need to go lift today.’ It’s more along the lines of, ‘Oh, I get to lift today.’”

That, of course, is exactly what Harbaugh wants to hear. He said he is impressed where the team is from a strength and conditioning standpoint.

"I like what they’ve done over the summer just looking at them," Harbaugh said at media day. "They look good and healthy and stronger."