Kate Upton trains with Marines for charity

DETROIT — Kate Upton is used to working out to prepare for swimsuit photo shoots, but it still wasn't easy for the model to do a workout with the U.S. Marines. Upton worked out with Marines in Detroit to promote the upcoming Marine Week celebration in the city.

Upton struggled a bit at the end, but was able to complete the training routine that involved a series of aerobic exercises and running as her fiance, Detroit Tigers pitcher Justin Verlander, watched from afar. Upton joined several other Tigers players' wives and significant others in the session at Wayne State University's athletic complex that was led by Gunnery Sgt. Sara Pacheco, a Marine Corps fitness instructor.

"It was (a) very hard workout," Upton said following the exercise session, which she concluded by collapsing to the grass in an exhausted embrace with a fellow workout warrior. "I knew it was going to be hard. The Marines are very tough."

Verlander, a former American League most valuable player and winner of the Cy Young award as the league's top pitcher, said afterward that he was proud of Upton for her efforts.

"I think it's easy to show your support with words. I think going out there and doing that workout I think really shows how much she supports (the military)," Verlander said. He is the founder of the Wins for Warriors charity that supports military service members and their families.

Upton, a world-famous model who has appeared three times on the cover of the Sports Illustrated swimsuit issue, was on hand to promote Marine Week, which runs Sept. 6-10, and is designed to provide the public with a better understanding of the Corps and its mission and the chance to connect with hundreds of Marines.

She wrote on Instagram, "I have few more workouts to go before I'm ready."