Mr. Jill's offers the best trainers in the county. Every trainer is ACE certified and has a college degree. We make it a point to make sure that every trainer we provide is up to date with the most current trends on fitness and nutrition. We take pride in our knowledge that we can extend to our clients. 


Jill Koval- Kahler 

Jill Is the owner and founder of Mr. Jill's Body Firm. Jill has a Masters Degree in Exercise Physiology. Jill is certified a Personal Fitness Trainer by the American Council on Exercise (ACE) and the American College of Sports Medicine (ACSM). Jill is a Certified Plant Based Eating Specialist by Cornell University. She is a committed vegan and a vegan dietary specialist. 



Livia found her passion for sport on the tennis court at the age of six. She played tennis competitively throughout high school and college. In order to improve her game, Livia ran and weight trained consistently. This sport schedule gave Livia the intense desire to pursue physical fitness as a career. Although Livia no longer plays tennis, she is now an avid cyclist. Not only does she ride four times per week for a weekly average of more than 150 miles, Livia also maintains her strength training habit of two times per week. Exercise continues to play an very important role in her life.

Livia began her career as a Professional trainer for Mr. Jill’s Body Firm in October 2000. She has been a tremendous asset to Mr. Jill’s. Aside from being one of the best Trainers in the industry, Livia is always concerned about her quality of training and the well being of her clientele. She is always well prepared in advance for each and every client session with new and innovative exercises. Even after several years of training, a client never has the same workout! Livia always gives 100%!

In Livia’s words, “It has been such a great experience working at Mr. Jill’s. It feels like family. I am very proud to be a part of the Mr. Jill’s team.”

Roxy Kahler



Professional Trainer for Mr. Jill’s for over ten years, Ian has had the privilege of training many Orange County teens, young adults, baby boomers and mature adults. He is extremely innovative in his program design. He values education and actively pursues advanced practice courses in order to enhance his already impressive academic achievements.

Ian is a graduate of Chapman University with a Bachelors degree in Movement/Exercise Science with an emphasis in Athletic Training. Ian is certified by the National Strength and Conditioning Association (NSCA) as a certified strength and conditioning specialist. Additionally, he is a certified Resist-A-Ball Core Team Instructor.


Trainer, Daniel Gustin has a Bachelors of Science degree from the University of Arizona with an emphasis in Psychology, Bio Chemistry, and Nutrition Science. In addition, Daniel is a Certified Personal Trainer with American College of Sports Medicine (ACSM) and a Certified EMT-B. He has a wonderful heart working with the special needs. Daniel is a fantastic addition to the Mr. Jill's Training Staff.



Kelly is... 


Exercise has no age limits -- you're never too old to start. This notion applies to personal fitness trainers, as well. After a successful career as a software engineering executive, Kurt retired at age 48. Reflecting on the years of spending far too many hours confined to conference rooms and airplanes, Kurt's first order of business was to improve his personal health and fitness to ensure a long and very active retirement.

Raquel Kahler

Raquel is currently a third year college student studying biology with an emphasis in genetics. She is an exercise enthusiast, health aficionado, animal lover, vegan and vegetarian cook, and blogger.
Raquel has been a vegetarian for about 4 years now, and a vegan for over a year. She grew up in an semi-omnivore household in lovely Orange County with a family that had a central focus on health and fitness. She says semi-omnivore because, "the meat we ate was limited – red meat was never found in our house, and my mom was highly allergic to seafood. We only ever ate chicken or the occasional turkey for Thanksgiving (white meat only!). Eggs weren't used that often, and milk was had with cereal. We didn’t eat this way in order to avoid eating animals; we ate this way because eggs have a lot of cholesterol, read meat is bad for your heart, and the best liquid you can possibly drink is water." In addition to Raquel's busy school schedule and keeping up with her OvenMittsBlog, we are very fortunate to have Raquel write the Mr. Jill's monthly newsletter, Fitness Facts, for the current clients of Mr. Jill's. She does a fantastic job bringing important information about health, fitness, and nutrition to the Mr. Jill's clients through the monthly newsletter.