Our Team

Chris Marhefka

Chris Marhefka

Owner, Gym Boss

Chris created B3 to have a direct impact on people’s lives, health and fitness. When he was first getting B3 started, he was managing a catering company, working as a bartender, and living out of his car. Now B3 Gym is one of the most prominent fitness communities in Gainesville. He is a CrossFit Level 1, Level 2, and Mobility coach as well as Precision Nutrition Level 1 coach and ACSM-CPT. Chris’s vision is to help one million people improve their health and happiness, and he is well on his way to fulfilling that goal.

Carlee Marhefka

Carlee Marhefka


Carlee started as a member of B3 at its very beginning. She was out of shape and exhausted at 20 years old, and since then has fallen in love with the business and the feeling of getting stronger every day. She is now happy, healthy, and in the best shape of her life. This super fit lady also eats more than most full grown men (all except Jason). As the Co-Owner of B3 as well as a Certified Personal Trainer, she’s here to spread her love of burpees and healthy living with the entire B3 community.


Karen Colwell

General Manager

Karen Colwell comes to Gainesville from CrossFit 405 in Oklahoma City, where she worked as the Head Coach and General Manager for several years. Prior to her time there, Colwell worked at Stanford University logging 1,500 hours of various varsity sports and techniques, including mobility. Colwell is an NSCA Certified Strength and Conditioning Specialist, a USA Weightlifting Sports Performance Coach, and has her Cross Fit Level I and II Certification. Karen got into CrossFit after being a competitive rower for 12 years. After she graduated from the University of Michigan, she continued training with the US National Team. Soon after she stopped rowing, she started competing in CrossFit and Olympic weightlifting competitions and quit her desk job to pursue a coaching career.

Jason Lentz

Jason Lentz (Bear)

Head Coach/Operations Director

Jason, the strongest man in the gym, started out at B3 as an intern in the summer of 2014. After that, Chris never told him to leave… So he stayed! Jason’s many certifications include CrossFit Level 1, CrossFit Mobility, and Certified Strength and Conditioning Specialist from the National Sports and Conditioning Association. His nickname “Bear” comes from his brute strength, but he’s also sweet as a teddy bear. Make him do a running WOD, though, and he won’t be too happy.

Sarah Houder

Sarah Houder

Executive Assistant

Sarah wore many career hats before joining B3. She has a bachelor’s in biology from the University of Colorado and a degree in Baking and Pastry from the Art Institute of Washington, DC. She is now our incredible Executive Assistant, taking every task thrown at her and turning out a beautiful, organized product. She is inspired by the community and the drive of our members to improve their lives every day. There is no doubt that Sarah has helped enhance the entire B3 team’s communication and collaboration. And on top of that, she can bake a delicious Paleo cake and has two adorable pets, Motu the dog and Yoyo the cat.


Jonas (“Sweet Baby Jonas”)

CrossFit Coach, Personal Trainer

Gainz Guru Jonas stands behind the amazing community and potential of B3. He’s here to help coach and encourage our members throughout their fitness journeys. He’s been a military solider for 8 years and a CrossFit coach for 4 years. He has CrossFit Level 1 and USA Weightlifting Level 1 certifications. One of Jonas’s strengths is individualization; he loves helping each of our members set goals and achieve them. Jonas also loves getting inked up—he has over fifty tattoos and still counting! His dream goal is to meet President Obama and take him through a series of calisthenics exercises.


Amy D. Hester (AmyD)

Running Coach

As a certified running coach, Amy brings a unique and valuable level of expertise to B3. After moving back to Gainesville from Japan, Amy was looking for a gym that was welcoming yet challenging. B3 has provided that for her and then some; while she loves the workouts, the community here keeps her coming back just as much. Every Sunday morning, Amy leads trail runs around Gainesville for our members. Her passion for endurance running has transferred over into some her favorite WODs: long chippers and anything that takes perseverance.


Kyle Harris

Coach / Personal Trainer

Kyle began as an intern for the 2016 Fall semester, but has stayed on and is now part of the B3 team. He has earned his A.A. in Exercise Science from Santa Fe College, and earned his B.S. in Applied Physiology and Kinesiology specializing in Fitness/Wellness from the University of Florida. He is a certified personal trainer through the American Council on Exercise, and has a passion for strength training, conditioning, and assisting others in achieving their fitness goals. He is also a Marine Corps veteran, serving four years in their Security Forces before starting college. When not lifting or coaching, Kyle enjoys composing music on his guitar, playing golf, and watching football. .

Cory Kessler

Corey Kessler

Member/Future Coach

Don’t let the beard fool you, Corey is a self-proclaimed “pretty big softy.” He joined B3 as a member, needing something new in his life. Now Corey’s here to get stronger, faster, and help his fellow athletes do the same. He is a certified CrossFit Level 1 coach, and loves to bring knowledge about health and fitness to others.


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