About 5280 CrossFit

About Jason Grubb, Owner

Founder & Owner, 5280 CrossFit

Before and After Jason Grubb at 5280 CrssFit

My gradual slide towards a thicker waistband and deconditioned body didn’t happen overnight. It took years of drinking IPAs, eating pizza, overdosing on carbs and sugars. Years of trying to stay ‘fit’ by cycling in and out of fitness gyms made little difference as I tried to find my way back to feeling and looking good.

I started my rediscovery of health and fitness just over 4 years ago… After years of trying to do it on my own, I joined a CrossFit gym. Supported by my coaches and peers in group classes, I rewrote my future one day at a time. 

Today, as a 42 year old with 4 kids (two under the age of 4), I’m in the best shape of my life. I love working hard, experiencing dramatic results, feeling strong, and knowing I’m healthy.

My passion is to inspire and lead others to achieve their unique goals and dreams in life, health and fitness. 

Want to chat? Don’t hesitate to email me!

Meet the Coaches

Jason Grubb

Jason Grubb

Owner | Coach

Jason is a competitive CrossFit athlete who loves the Colorado outdoors. As a husband and father of four kids (from teenagers to a toddler), he aims to stay healthy and fit for the long run. He fully intends to engage in sports, hiking, backpacking, and fly-fishing with his kids well into their adult years. Jason was a competitive gymnast through his teenage years and enjoyed running and cycling through his twenties and thirties. He discovered CrossFit at age 38 and fell in love with the community, the challenge of the workouts, and the results.

Jason doesn’t consider anything from Apple, REI, or Macallan an indulgence. He prefers shorts to jeans and would love to never wear a suit again in his life – if at all possible. Colorado has always been, and will always be his home.


  • CrossFit Level 1 Certificate
  • CrossFit Level 2 Certificate
  • CrossFit Gymnastics Certificate
  • CrossFit Weightlifting Certificate
  • Adult CPR/AED and Child CPR
Erin Murphy

Erin Murphy

Coach, Personal Trainer, Nutrition Coach

Erin found CrossFit while studying Exercise Science at Fort Lewis College in 2013. Originally from the Chicago area, she explored several areas of the country and taught kids in Thailand, before happily making Denver and 5280 CrossFit her home. CrossFit provides the wonderful combination of competition, community, nutrition, and fun that keeps her motivated. Helping people of all backgrounds, ages, and abilities thrive and see that fitness can be something they enjoy, is what makes coaching her happy place. She plans to use CrossFit as a way to stay strong and healthy throughout her life and wants to help others do the same.

Nothing puts a bigger smile on her face than pistol squats, outdoor adventures (in the sun or snow), and feeling her best, although she does struggle with eating copious amounts of peanut butter, spicy foods, and enjoying a good beer. Nobody’s perfect, right?!


  • CrossFit Level 1 Certificate
  • CrossFit Level 2 Certificate
  • Precision Nutrition Level 1
  • CrossFit Kids Certificate
  • CrossFit Movement and Mobility Certificate
  • Adult CPR/AED and Child CPR
Spencer Kemp

Spencer Kemp

Coach, Personal Trainer, Barbell Coach

While serving in the US Air Force, Spence discovered a passion for all things fitness. After separating from the military, he worked as a personal trainer for several years. While working at a conventional gym, he was intrigued by a video circulating the internet of the Hero WOD called “The Seven.” Having never done CrossFit before, and not having a coach to advise heavily scaling the workout, it took him 1 hour and 17 minutes to complete. Freshly determined to improve, Spence began studying the sport of CrossFit. Within a few months he knew that he his passion for fitness had evolved into a passion for constantly varied functional movements done at a high intensity. Specifically, Fran, Squats, Muscle Ups, and Snatches. His PR “The Seven” time is now 27:15.


  • CrossFit Level 1 Certificate
  • CrossFit Level 2 Certificate
  • Adult CPR/AED and Child CPR
Callie Moore

Callie Moore

Yoga Instructor

Callie started practicing yoga in 2002 in Austin, TX. Her connection to mind, body, and health through the practice inspired her to start her journey as a teacher. She completed her first 200-hour teacher training in 2008 in Boulder, CO to deepen her knowledge. Additionally, she completed advanced trainings at Corepower in 2013 and has been teaching ever since. Callie has also led numerous teacher trainings for both new and seasoned teachers.

She has a passion for health and a desire to help people live to their fullest potential!


  • Level 2 Power Yoga Certification

(Re)Discover Health and Fitness

We combine the best and most effective elements of conditioning, body weight movements and weightlifting to create an easily tailored fitness experience for people of all ages and fitness levels.

We incorporate many common, everyday movements into training. Think of moving from sitting to standing up, picking up something from the ground, or putting luggage in an overhead compartment. Those movements (and many others) are combined into varying combinations to form high-intensity workouts. These workouts are quick, potent, very effective, and never boring.

We believe and know that nutrition is critical to optimizing human function, and 5280 CrossFit is here to help you implement a personalized nutrition plan that works for you and your life.

(Re)Write Your Future

Your future ‘self’ is not set in stone. You have the power, starting now, to move in the right direction.

We believe that safety, efficacy, and efficiency are the three most important and interdependent facets of a great fitness program. CrossFit is, quite simply, a sport—the “sport of fitness.” We’ve learned that harnessing the natural camaraderie, collaboration, and fun of sport or game yields a potent intensity that cannot be matched by other means.

Overall, the aim of CrossFit is to forge a broad, general and inclusive fitness supported by measurable, observable and repeatable results. The program prepares our members for any physical contingency—not only for the unknown but for the unknowable, too.


“The magic is in the movement, the art is in the programming, the science is in the explanation, and the fun is in the community.”

– Greg Glassman, Founder of CrossFit

Your path to success starts with a New Client Consultation:

We'll take a tour of the fitness center and chat to discover:

  • Your short and long term goals.
  • Your bright spots (what are you already doing right).
  • The best path to your specific goals.

Click here to schedule your New Client Consultation.