CrossFit OverWatch Coaches 

With over 60-years of combined CrossFitting and coaching, CrossFit OverWatch's team is dedicated to making sure that you reach your personal goals in a safe and effective manner.  Our coaches follow the CrossFit methodology of constantly varied functional movements performed at high intensity. All CrossFit workouts are based on functional movements, and these movements reflect the best

aspects of gymnastics, weightlifting, running, rowing and more.

Our Coaches are Masters of helping you to modify to your ability!

Jimmy Greninger

  • Owner/Founder of CrossFit OverWatch

  • BA degree in Psychology from CSUN  (California State University Northridge)

  • CrossFit Level 1 Coach

  • National Academy of Sports Medicine

  • (NASM CPT)

  • USAW LV1 (under Coach G. Pendlay)

  • API Caveman Certified Instructor

  • UFC LV5 Certified Head Ultimate Trainer

  • BioDensity Certified

  • DotFit Nutrition/ Supplements Certified

  • CPR/AED Certified

  • CrossFit Football Cert (Inaugural class) 

  • CrossFit Running/Endurance Cert

  • CrossFit Mobility Cert (under K. Starr)

  • CrossFit Nutrition Cert (under R. Wolf)

  • CQC Scientific Fighting Congress Member (under Hock Hochheim)

  • CA and NV State Athletic Commission Credentialed

  • Self proclaimed Ping Pong Champion of the Universe!


 Jimmy is Owner and Operator of The HANGAR/CrossFit OverWatch. Jimmy was a highly recruited 2 sport Athlete and enjoyed successful Div1 Football career and a shot in the NFL before getting injured. In 2006 Jimmy found CrossFit through his childhood friend, Jeremy Jones, founder of Diablo CrossFit and was instantly engulfed into the CF lifestyle. Jimmy embraced his love for Coaching and started teaching CrossFit in 2006 and received his CF LV1 in 2008. Coach Jimmy became a Professional UFC MMA Trainer/Corner man and has worked with some of the biggest Super Stars and Champions of the UFC and StrikeForce. Coach Jimmy has also prepared and trained several active Marines, Poolees, NAVY SEALs, ARMY Rangers, Green Berets, Para-Jumpers, SWAT and NFL players. Jimmy Created/designed and implemented the “DUT” Training Program that is run in all UFC Gym locations (over 100) World Wide. He has helped to build some of the largest CrossFit, Fitness and Nutrition programs in California. Jimmy is co-editor of the published “CaveMan Diet Handbook” and Author of the “30-day Paleo Challenge.”  He is a proud Father of 2 little boy BEASTS!

Jenna Graham

  • CrossFit Level 1 Trainer

Jenna is HUGE wrapped up in a little package. She has had a passion for sports and outdoor activities her whole life.  Jenna grew up playing soccer, volleyball, field hockey and softball.  Jenna played field hockey all the way through college and played for UC Berkeley.  Jenna transitioned towards cycling and climbing as her primary outdoor activities.


Captain Jenna, enjoys working for the City of Mountain View Fire Department for over 15 years.  Jenna truly loves the thrill of driving a fire engine for a living in addition to providing medical care to all of her patients.  Jenna found CrossFit to be the perfect match for the strength and fitness requirements of her profession.

Jenna has been involved with CrossFit for many years, but just over the past year made more of a commitment to CrossFit as her primary strength and conditioning.  

Lori Santo

  • Rock Steady Boxing Certified


Coach Lori lives in San Jose and became involved with Rock Steady Boxing from a personal level, having someone in her life living with Parkinson's. 
Her interest in RSB stems from her personal goals in working out to stay healthy and eating clean. After hearing about the Rock Steady program, she found herself wanting to learn more about why it was so effective and wanted to include that in personal training on a one-on-one level.  After training in Indianapolis, IN, as a certified RSB Coach, in those few days she realized the passion she had in working with Persons with Parkinson's (pwP) was something she had to get involved with! 
Today, she commits her time to RSB East Bay working with our Parkinson's clients as Coach and many will meet her during the Assessment phase of their decision to "fight back" against Parkinson's!


Cale Crawford

  • CrossFit Level 1 Trainer

Cale Crawford is well known as being the "Gentle Giant" at Crossfit OverWatch. Cale's gentle demeanor and low key approach makes him a gym favorite at OverWatch.  Cale currently oversees the 5AM classes at OverWatch. Cale and Jimmy have been training together since back in the day at the first ever UFC Gym

(10+ years!).

Jose Ayala

  • CrossFit Level 1 Trainer

Jose grew up playing Football and Basketball in High School. He was also the Athletics Director at Walnut Creek Intermediate and Foothill middle School where he implemented a modified version of our OverWatch program for the kids. Jose has been an avid CrossFitter for 6+ years at OverWatch.  Most days you will find Jose under the barbell looking to perfect his lifts. CrossFit is a natural fit for Jose since he served 8-years in the Marine Corps. Jose's always down for a "quick Murph" or a 2 mile tire drag when the Raiders lose! Jose's "2ndWOD" and weekend "Partners" programming are Gym favorites.

Jose proudly serves our community as an active duty EMT.

​        Tiffani Yarnell

  • CrossFit Level 1 Trainer


Tiffany grew up playing multiple sports.

She played club soccer for 12 years and boxed for 8 years. Tiff has been doing CrossFit for 5 years and has been at CrossFit OverWatch for over 3 years. She's noticed a huge difference in herself not only strength, but also speed, power, and overall appearance. She began doing CrossFit because She was looking for a challenge and hated walking around the gym without any idea of what to do next. "I can’t pick a favorite workout but I LOVE Chipper style workouts, I guess that makes me a glutton for punishment."

Her goal is to make it to the CF games and she would love to help out members reach their own fitness goals. 

   Will Travato

  • Crossfit level 1 Trainer

Coach Will came to us as newbie to both the CrossFit world and here at OverWatch. He has embraced the lifestyle full force ever since starting a little over 3 years and ago. Having played competitive soccer since the age of 9, Will was a quick fit to CrossFit's high intensity driven workouts.  He is rapidly gaining experience Coaching, as he is one of those "can't stay away from the gym" types and is a member favorite here! Will is motivated to improve and learn on his own fitness capabilities as well as help others here at OverWatch. Will is a huge fan of AFAFP workouts as he loves pushing for the best time and of course enjoys a little friendly competition ;)



Tel. (925) 785-1272

1990 Olivera Rd Ste#D
Concord, CA 94520





Mon-Thursday class: 5am open gym w/ Coach

6,9am and 4,5,6pm

Friday class: 5am open gym w/ Coach,

6,9am, 4pm, 5pm

Saturday class: 8am and 9am

Sunday class: 8:30am and 9:30am


Rock Steady Boxing (Parkinson's Group Only)

Monday, Wednesday, Friday "online classes"

Additional T and Th "In Facility" classes: 

10:30-11:30 and 12pm- 1:00pm (RSVP only)




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(925) 785-1272

1990 Olivera Rd Ste#D.

Concord, CA 94520

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