Rob Kardashian’s trainer talks about workout plans, anticipated challenges

After missing sister Kim Kardashian’s wedding amidst a reported clash with family over his weight, Rob Kardashian is determined to get in shape — and trainer Gunnar Peterson said he is confident his longtime friend will meet that goal.

“I think Rob knows exactly what to do. He’s worked out [before] and he’s focused,” Gunnar told People, explaining Rob texted him before he left Paris to request a personal weight-loss plan. They’ve since put the plan into motion. “We’re doing intervals with strength movements: squats, the sled, swings and push presses. It’s about getting his heart rate up and keeping it up.”

Gunnar said both he and Rob agree the goal isn’t to reach a certain weight, but for the only Kardashian son to feel good about his body.

“I don’t have a scale, I’m not big on measurements,” Gunnar said. “Until a person looks in the mirror and is happy with themselves, you have not reached your fitness goals.”

Rob leaving Dancing With the Stars practice in 2011.

To help Rob stay motivated, Gunnar said he’s coming up with engaging workouts.

“I’m a firm believer in trying to make something that might not be considered fun by a lot of people, fun. And hopefully that makes the person have a positive association with it and they want to come back,” said Gunnar, who also trains Bruce Willis and Slyvester Stallone. “Rob works out in beast mode. When I see him, we laugh, have fun and he gets after it hard at the gym. I know he can do this.”

The biggest obstacle Gunnar anticipates is fitting the workouts into Rob’s schedule.

“People forget he’s in the show, he has the sock business and he has other interests. But with a good diet, the right sleep and steady workouts, he will see changes. He’ll start seeing and feeling it in a couple of weeks and will see major changes in six to eight weeks.”