(LOS ANGELES) -- Rob Kardashian has made it clear that he wants to get back in shape.
According to his trainer, Gunnar Peterson, he's working hard to get there.
"Rob is such a solid guy, when he gets in here. I don't care if he weighs 50, 100 or 200 pounds. He works like an athlete," he told E! News. "He never tries to beg out of a set. He never tries to hop off the cardio a minute or two before. He goes the distance every time."
Peterson, who called Kardashian "a solid basketball player," "a serious runner," and a "serious athlete," added that they work out together as often as possible, though the reality TV star's schedule can get in the way sometimes. However, he added, "if it was Rob on his own, he'd be in every day."
"There's no doubt in my mind. With 26 years of training experience of doing this, I can tell you without hesitation that Rob Kardashian will get back to his best shape ever. There's not one doubt in my mind," Peterson said.
Copyright 2014 ABC News Radio