201 Oak Street Pembroke, MA 02359     |     781-319-7154     |     info@crossfitmagnitude.com     |       Facebook   Twitter   Instagram

Christopher O’Brien – Owner/Head Coach/Programmer













Chris has been passionate about sports and fitness for his entire life. With over 20 years experience training with functional movements, a degree in Exercise Science, an Infantryman in the US Army,  and over a decade working with people from all walks of life, Chris has developed the skills necessary to guide others in their quest towards greater fitness.

CrossFit and Chris were first introduced after a night browsing the internets fitness forums. The following morning, Chris decided to complete his first workout called ‘Fran’, a well known ‘Benchmark WOD’ by the CrossFit community, and found himself pale, disoriented, and gasping for air afterwards. With a less than desirable outcome, Chris began to question his current approach to fitness. From that day on, Chris has entrenched himself with understanding, implementing, and teaching others the fundamentals of the CrossFit methodology.

As a former U.S. Army Soldier, extreme outdoorsman, and avid CrossFitter, Chris believes that any individual seeking to enhance all aspects of their life, both mentally and physically, can do so by making CrossFit a part of their lifestyle.

Chris is looking forward to sharing his love of fitness with you through fun, inspiring, and educational workouts that will help you reach your goals!

Bachelor of Science in Exercise Physiology

Certified CrossFit Level 3 Trainer (CF-L3)

USA Weightlifting Sport Performance Coach

CrossFit Gymnastics Instructor

CrossFit Strongman Instructor

CrossFit Kettle Bell Instructor

CrossFit Judge

The Movement Fix Coach’s Workshop attendee under Dr. Ryan DeBell

A.C.E Certified Personal Trainer

CPR/AED certified

Military background

Jami H. (Miss Awesome) – Coach


Jami has been a South Shore girl her entire life, calling the 7-mile peninsula of Hull her hometown.  Growing up in the very (VERY) small town, she stayed busy playing baseball, soccer, cheerleading, and singing.

Her love for lifting weights started as soon as any of her friends had a license to drive to the closest gym.  She started with group classes but quickly found herself as the only girl in the weight-room daily and loved it.  From then on, she was a self-proclaimed gym rat, at one point having memberships at three separate facilities.

Her education and work experience led her to full-time employment at Reebok Headquarters, where she has worked in Logistics and Footwear Quality for the last 5 years.  It was at Reebok, during an all-employee fitness event, that Jami was introduced to CrossFit.  She completed a bodyweight WOD of pushups, sit-ups and squats with 400 of her closes Reebok friends and smiled the entire time.  She signed up for On-Ramp/Foundations at Reebok CrossFit One that very same day.

Having an employee box on the Reebok campus provided endless opportunities to learn, train, and become part of the amazing CrossFit Community.  Jami completed her Level 1 Seminar and began her coaching journey at RCF1, shadowing and learning from some of the best athletes and coaches known to the sport!  She continued coaching outside of Reebok, most recently landing her in the wonderful Magnitude community!

Jami is usually smiling, laughing, or singing; sometimes all at the same time.  She loves the ‘fun’ part of CrossFit, like thrusters!  No, just kidding!!  Her favorite CF moments include throwing around heavy weight, high-fives, The Filthy Fifty, slow claps, and the feeling of pride after helping someone do something they never imagined they could!

CF-L2 CrossFit Trainer

CF Gymnastics

BA Criminal Justice; UMass

MA Organizational Management; Ashford University

Laurie L. – Coach


CF-L1 CrossFit Trainer

Caitlin C. – Coach



CF-L2 CrossFit Trainer

CrossFit Kids and Teens Instructor

CrossFit Endurance Instructor

CrossFit Nutrition Instructor

Institute of Integrative Nutrition Holistic Health Coach

5x Boston Marathon Runner

ACSM Certified Personal Trainer
Madd Dogg Athletics Spin Instructor
CPR Certified

To get started with your FREE Intro – Click HERE! 

If you would like to set up a one on one personal training session with one of our experienced Coaches, please contact Chris at info@crossfitmagnitude.com or call 781-319-7154.