Meet The Team



Russ Nuffer

Co-Founder, CEO

Russ is a nationally certified personal trainer with the American College of Sports Medicine and a certified Double Goal Coach by Positive Coaching Alliance. In addition to founding GrowFit, he's the Director of Fitness for The Fit Kids Foundation, a 501(c)(3) non-profit corporation that brings a free after-school fitness program to children in underserved communities. He was also on the advisory committee of Stanford GOALS, a research project aimed to improve health through sports and physical activity. With a lifetime love of sports and the outdoors, he enjoys helping people discover the fun in physical fitness and is passionate about introducing a healthy lifestyle to young children. Russ graduated from Cal Poly, San Luis Obispo with a BS in Kinesiology (concentration in Physical Therapy) and a minor in Psychology.


Ashley Schildwachter

Director of Business Development

Ashley has six years of experience teaching in urban settings with students ages 6-14. Prior to GrowFit, Ashley worked as a special education teacher and consultant in the Bay Area and in New York City. She earned her bachelor’s degree in Human Development and International Studies from Boston College and her Masters in Education from the New York City Teaching Fellows program at Long Island University, Brooklyn. Ashley was a Division I scholarship swimmer at Boston College. As a lifetime athlete and health advocate, she is inspired to work at GrowFit because she believes in the company’s desire to support the well being of youth through physical fitness. She is passionate about providing kids with a healthy and fun outlet for their energy and a space where they can make friends in a team environment.


Clare Barbella

Director of Curriculum

Clare has been instructing youth fitness classes for over eight years. She earned her Bachelors in Science in Health Education from San Francisco State University, where she developed a passion for health and teaching. In college, she volunteered her time as a Health Educator facilitating health workshops for high school teens. Upon graduation, Clare pursued a career as a physical education teacher. Additionally, Clare has taught basketball and multi-sport after school enrichment classes. She also teaches adult kickboxing classes in her spare time. She continues her professional development through the International Baccalaureate program and has recently finished her Level 1 certification.


Tracy Maxwell

Director of Sales

Tracy has 20 years experience in the sales field. She specializes in technology, market research and educational sales. Prior to joining the GrowFit team, Tracy’s work served special needs students. She brings a passion for products and services that enable children to grow, develop and become their best. In her spare time, Tracy enjoys gardening, hiking, yoga and spending quality time with her family in the Utah area.


Bernie Castro

Sports Program Manager and Educator

Bernie has taught physical education for two years with GrowFit. Prior to GrowFit, Bernie coached basketball at Bayside Stem Academy and St.Peter's School in San Francisco. Additionally, he has coached basketball at the middle school and junior high levels and has played basketball and football in high school. He is passionate about coaching and enjoys teaching youth sportsmanship and the concept of teamwork.


Devin Harris

Educator & Athletic Director

Devin has over 14 years of experience working with children. Prior to joining GrowFit, Devin was as an Outdoor Education teacher and basketball coach for both elementary and middle school students. In his spare time, he enjoys being outdoors, dancing and playing baseball. Devin is currently pursuing a degree in child development and looks forward to a long career in physical education.


Frank Ciardullo


Frank has five years of experience teaching physical education in international settings. Prior to GrowFit, Frank was an athletic director, PE teacher and coach. Additionally, he has coached and taught soccer, basketball, badminton and futsal teams at the middle school and high school level. He earned his college diploma in recreation and leisure services from Ontario College, where he followed his passion of athletics and teaching. He was inspired to teach for GrowFit after moving from Malaysia and learning the passion of the organization. He is excited about teaching and coaching and looks forward to inspiring students of all ability levels.


Winson Yip


Winson has three years of combined experience teaching and assistant teaching in elementary and middle school program settings with students ages 5 to 13. Prior to GrowFit, Winston was involved in many athletics. Additionally, he was in the volleyball club at the University of Santa Cruz. He earned his degree in environmental sciences from the University of Santa Cruz, where he found his passion for teaching and working with youth. He was inspired to work for GrowFit after realizing teaching was what he loves to do. He is passionate about being active and working with kids and looks forward to inspiring the students to love being active.


Yvonne Gragnola


Yvonne has many years of experience working with kids in elementary and middle school settings. Yvonne joined the GrowFit team in 2017 and has been a natural fit. Yvonne adds a tremendous amount of compassion to GrowFit. She currently teaches kids from 4 to 16 years old and looks forward to a long career in education.

Joe Callinan

Co-Founder, Advisor and Director of Finance

Prior to GrowFit, Joe spent 8 years as a Product Leader for a $4 billion dollar technology company. During that time he was the Product Leader for two new products, QuickBooks Self-Employed and QuickBooks Financing. Joe earned a BS and MBA from Cal Poly, San Luis Obispo and is a Certified Public Accountant.

Athena Herrera


Athena is a recent graduate at San Jose State University where she studied Sports Medicine/Kinesiology. She has worked in the fitness industry as a Certified Personal Trainer but has found her passion is working with children. She has worked as a children’s coach in Mixed Martial Arts for 8 years and is the head coach of a local high schools first ever girls wrestling team. She has a passion to make exercise and fitness inclusive and enjoyable for everyone.

Dolly Nave-Kilpatrick


Dolly has 5 years of experience teaching physical education in after school and non profit program settings with students ages 4 to 14. Prior to GrowFit, Dolly went to school for early childhood education and dental assisting. Additionally, she has coached/taught at Novato High School for 4 years at varsity level and was a cheerleader from age 4 till college. Having experience working with kids made her interested in working with them for a career. She is passionate about helping kids be active and looks forward to a long career in teaching.

Randell Manzon


Randell is going into his 8th year of combined coaching and teaching in various school and high level settings. Prior to working with GrowFit, he worked as a substitute teacher in Union City. Randell graduated from California State University-East Bay with a Bachelors of Science Degree in Kinesiology and an option in Physical Education Teaching. On top of teaching, Randell has a passion for coaching volleyball. He has coached for the last 5 years at the high school and club level. He is excited to work with GrowFit and a long career in teaching physical education.