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Bob Grenier

Owner/Head Coach

Bob Grenier

Owner/Head Coach


Plain and simple, this is my passion. When I changed career paths from finance to fitness in 2009, it was one of the best decisions of my life.  The ability to transform an individual physically—and more important, mentally—is the best part of what I do.  I was born and raised in Lowell, and there is nowhere else I could have envisioned CrossFit Merrimack taking root.  There is no part of my life that CrossFit has not changed or touched in some way.  More than the weight I’ve lost or strength I’ve gained, CrossFit has granted me the mental toughness to tackle a workout or anything in my life that seems impossible, and it is that sense of purpose that drives me to be better each day.

Why CrossFit? Working as a personal trainer in conventional gyms, coaching CrossFit and having played competitive hockey up through college, I have been in and out of gyms my entire life. Having said that, finding CrossFit was for me a revelation.  No more leg days or Tuesdays-are-chest-and-triceps.

I am a walking poster board for what the “CrossFit Lifestyle” is capable of.  My fitness journey started out like a lot of New Englanders: in hockey rinks 24/7 up through college.  I was lucky enough in my younger years to be able to rely on sports to push my physical fitness.  Fast-forward to post-college: working in finance, lack of exercise, and bad nutrition habits resulted in a person I soon did not recognize.

More than just being overweight, I was unhealthy.  Fitness had no place in my life and it showed when I weighed in at 260 pounds.  It is this point in my life that I can relate to so many of the new members that come in the gym. So I know how you feel. It can feel overwhelming, and you don’t know where to begin.  So when I say I have a plan for you, I mean it!

In total, I ended up dropping about 80 pounds and then gaining back healthy weight in the form of muscle.

I owe who I am today to my wife, the coaches and community at CFM, the CrossFit community at large, and all friends and family, who supported and inspired me every step of the way.


  • CrossFit Level 2 Trainer
  • USA Weightlifting Sports Performance Level 1 Coach
  • Catapult Olympic Weightlifting Certification under Don McCauley
  • Attitude Nation Weightlifting Certification under Jon North
  • CrossFit Endurance Certified
  • Certified Personal Trainer – AM&F
  • CrossFit Judges Certified
  • American Red Cross CPR/AED Certified

2013, 2016 & 2018 Enterprise Bank Celebration of Excellence: Entrepreneur of The Year Nominee

Worcester State University Men’s varsity ice hockey