Pregnancy certainly isn’t slowing Hilary Duff down!
According to Pasternak, keeping Duff “in a cool room” and managing her heart rate during the first trimester was key.
“No impact, no hyper bouncing and plyometrics,” he tells PEOPLE. “You also want to back off stretching quite a bit. Women become hyper flexible when they’re pregnant.”
The pair, who work together three to five times a week, are concentrating on “low impact exercises” — including elliptical, incline heel walking and stairs — and avoiding any routines that focus on Duff’s abdomen.
“In the second trimester, [we're staying] away from any exercises where she’s lying on her back and that could put pressure on her midsection,” Pasternak explains. “We just go lighter and higher reps on certain exercises. So there’s nothing pressing against the stomach and breasts.”
As for maintaining her toned arms, Duff enjoys a “combination of free weights,” which will eventually be switched out for safer options later in her pregnancy. “We’ll replace dumbbell exercises with cable ones,” he says. “You can use a band at home too, you can use the elastics.”
Despite the mommy-friendly modifications, Pasternak insists working with Duff has been a breeze. “Hilary’s fit, young, [and] she’s healthy,” he says. “And the dad [Mike Comrie] is a professional athlete. So I think it’s going to be a great, beautiful, fit baby.”
And from her husband to sister Haylie Duff, the mom-to-be has plenty of good company during her workouts. “I’ve trained her and her sister together. Her sister’s in great shape and they work out on an equal level,” he adds.
Pasternak is also making sure Duff maintains a healthy diet, which includes minimal caffeine and a good substitute for her raw fish sushi cravings. “[I suggest] cooked fish low in mercury, like a piece of grilled salmon.”
Already a “good friend” of the family’s, Pasternak — who stays “up to date” on her pregnancy even when they’re not working up a sweat at the gym — is confident Duff is ready to tackle her latest role: motherhood.
“Her goals are to look great and feel great, especially now that she’s pregnant,” he shares. “[She'll be] an amazing mom! She’s a Texan girl! She’s got a lot of Southern hospitality, very sweet, very welcoming. She’s got a great balance in life.”
– Anya Leon with reporting by Thailan Pham