About Us

Learn More About Who We Are

ALLIE JACKSON

Co-Founder/Head Coach

Allie brings over a decade of experience in the health and fitness industry, blending high-level coaching with a deeply personal, client-centered approach. Before founding Mainstay Performance, she worked across a wide range of fitness settings—including commercial gyms, collegiate facilities, and government recreation centers. Over the years, she’s coached everyone from executives and athletes to stay-at-home parents and people returning to exercise after time away.

What unites her clients isn’t just their goals, it’s their drive to feel stronger, more confident, and more in control of their health. Allie is passionate about meeting people where they are, whether that means designing a plan for a busy professional balancing long hours, guiding someone new to strength training, or helping a former athlete rediscover their rhythm. Her mission is to make fitness sustainable, empowering, and aligned with the season of life you’re in, so you can thrive both in and out of the gym.

Qualifications:

- M.S. Exercise Science and Health Promotion

- Certified Master Health Coach

- Certified Personal Trainer

- Certified Nutrition Coach

- Certified Pre- & Postnatal Fitness Coach

- Registered Yoga Teacher

HARRISON MARICK

Co-Founder/Executive Coach

Harrison’s journey into health and wellness began as a collegiate athlete, where he first developed a deep appreciation for how training and recovery could fuel performance, both on the field and beyond. What started as a way to gain a competitive edge evolved into a lifelong commitment to movement, mindset, and sustainable habits. Today, Harrison serves as an executive for a multi-million dollar software firm, where he applies the same Mainstay principles he once used as an athlete to stay sharp, focused, and resilient in high-pressure environments.

In addition to his business experience, Harrison brings several years of personal and group training expertise to the table. His unique perspective, balancing the demands of leadership with the discipline of fitness, makes him especially attuned to the needs of busy professionals, former athletes, and those looking to reclaim consistency. Alongside Allie, he’s excited to help others build strength that lasts and create routines that support both peak performance and long-term health.

Qualifications:

- B.A. in Mathematics and Statistics

- CEO at Tiber Software

- Former Collegiate Athlete

- Certified Strength and Conditioning Specialist (2020-2023)