Blake Lively’s Incredible Bikini Body After Baby! Her Trainer Tells All

Just when you thought bikini season was over, Blake Lively proves that it’s still going strong!

The actress, 28, was spotted in Australia last week shooting scenes for the upcoming shark thriller The Shallows in a teeny, tiny, two-piece — and she looks fabulous. Since giving birth to her daughter James in December 2014 she’s been vocal about pressure on new moms to drop the baby weight. “There’s pressure to lose it…I think it’s silly,” she told the BBC in May, adding that she wasn’t “obsessing” about regaining her pre-baby physique at that time. Clearly her strategy has paid off!

So how did she do it? Lively’s trainer Don Saladino (who Lively said knows “how to kick my butt”) opened up to PEOPLE exclusively about the regimen she started in preparation for the upcoming movie. “This is way beyond having her just look great in a bikini,” he says. “That’s important, but it’s about keeping her energy level high and making sure that, day in and day out when she’s shooting this film, her recovery is optimal.”

With only two months to prep for the beachside shoot, Saladino increased Lively’s workouts from once or twice a week to five or six times a week. “We would do an upper body workout Monday, lower body Tuesday. Wednesday was a playful pool workout where she would do laps,” he says. “Thursday was upper body, Friday lower body, and Saturday we were focusing on the accessory movers: the arms, the shoulders.”

Lively started each session with foam rolling and “corrective work” to warm up before jumping into workouts of various intensities that could be adapted depending on how the actress was feeling.

“I told her to listen to her body,” Saladino says. “When you feel great, get on it. When you don’t feel great, shift down a gear. And when you feel like complete crap do really minimal work,” like 10 minutes on the elliptical.