The CORE57 Team is highly skilled, motivated and engaged with our clients. We take great pride in our ability to not only deliver the best services but in also creating lasting connections with all of our members. Being a member of CORE57 means being a part of our Tribe. 


Kolleen & Jason Losch

Founders & Owners of CORE57


Pauline Mandato

Director of Studio Operations

Chris Thiel

Director of Community Relations


Kolleen Losch, NASM-PT, CES,

Founder, Owner CORE57,

Master Trigger Point Trainer


Gaby Brubaker

Fitness Trainer


Rebecca Pedrick-Graybeck

Director of Training/

Nutrition Coach


Pam Giddings

Fitness Trainer


Sara Harrison

Fitness Trainer / Nutrition Coach


Chandalyn Pulmano

Fitness Trainer


Fran Ritter, BSN, RN, CDE

(Certified Diabetes Educator),

Trigger Point Trainer    


Matt Santos

Fitness Trainer


Tammy Thomson

Fitness Trainer


Erin Winn

Fitness Trainer    


“I’ve been with CORE since the beginning – almost 2 1/2 years! For me, just saying that says something about CORE’s program. I was the seasonal exerciser – workout for a couple of months, start seeing results and then stop thinking those results would last. I found CORE and stayed because the workouts are different every time I go, the fellow members are great and hold you accountable and the trainers carefully watch how you are performing the exercises to ensure proper form. They are not on a stage doing the exercises with you where they can’t notice if you are doing the moves correctly. The CORE weekly emails help me to understand the inner workings of my body and what I should and shouldn’t do for optimal health. And,I have seen results!I have dropped a size in clothing, become stronger, and my endurance has increased tremendously allowing me to run my first 1/2 marathon last year. I think the biggest thing I have noticed, especially during this time of year, is that I haven’t been sick. Two years ago, I would catch every illness my kids brought home. Not now!

The trainers at CORE have brought some unique exercises to the mix that really kick your butt (in a good way).I don’t see myself going anywhere else anytime soon!

Tracy H.

CORE57 Member

“At the beginning of the year I had to visit my doctor to have my blood pressure medicine increased. He informed me that walking on a treadmill was doing me no good and that I needed to start some type of interval training. Soon after my boss invited me to join her at a 5:45am class at CORE and I accepted. This was the beginning of the best decision I have ever made regarding my own health. Over the last 6 years I have been through multiple joint surgeries and had become tired, lazy and the heaviest I have ever been in my life. Starting off with more sore muscles than I even knew I had and with a 2 month break for yet another joint surgery I am now the healthiest I have been in a very long time. I have increased flexibility, more bend in my replacement knees and energy enough to attend 3 days a week. IT HAS TRULY BEEN A TRANSFORMATION!!!!I have dropped a size, 15 pounds, and reduced my blood pressure medicine to lower than it was before the start of the year. I give credit to Kolleen and the other trainers with my new and improved self.”

Jeanette C.

CORE57 Member


394 Commerce Street




6225 Atlanta Highway



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