Hollywood Trainer Jeanette Jenkins on How She's Helping Pink Strengthen Her Core After Baby No. 2

Pink was back at the gym six weeks after giving birth to son Jameson last December, and has been regularly meeting with Hollywood Trainer Jeanette Jenkins to help get her post-baby body back.

“Week one was about getting the body moving through all of the planes of motion and reconnecting the core back to movement,” Jenkins — who will serve as the Global Powerwalk Ambassadorfor almost 20 Dress for Success 5k Power Walks taking place around the world this summer — tells PEOPLE.

“The pelvis wall and transverse abdominus and all the muscles of the core have been working very hard from carrying and from labor, and it takes time and specific exercises to bring them back to function at their best.”

Jenkins and her team have been training with Pink four to five times a week to get her back in shape.

“Every session is different because it depends on what is going on in her body,” she says. “We mix up the methods of training — sculpting, rowing, boxing, dance, yoga, Pilates, power walking, jogging, running and cycling — for variety on the body, but there are some base moves that are done weekly to make sure we are specifically strengthening the pelvis wall, transverse abdominus and all the muscles of the core.”

Pink and Jenkins are also gearing up to cycle 100 miles next month to raise money for No Kid Hungry.

“This was Pink’s idea, and it’s amazing when you can combine your training with a cause so you can put even more purpose behind your exercise,” says Jenkins. “That’s another great reason why I love the Dress for Success Power Walk — it gives an additional purpose to training.”

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Pink has been posting her progress on Instagram — the singer hopes to drop a total of 35 lbs. of pregnancy weight — and Jenkins says she has no worry that her star client will be able to reach her goals.

“Pink loves to move her body and she is a natural athlete,” she says. “Her attitude is stellar! I wish everyone had her attitude towards movement. She’s an absolute joy and an inspiration to millions.”

As much as she is committed to losing the weight, Pink has posted about not being concerned with the number on the scale and focuses more on how she feels and having fun during her workouts.

“Pink has always been a very powerful woman and her attitude towards her post-baby body fits in line with her values,” says Jenkins. “We laugh at least 50 percent of every session — it’s so important to your health to love yourself and feel joy and let it resonate through your body and touch every cell.”