Science-Backed Strength & Personal Training in Downtown Boston
Founded on exercise science and behavioral psychology — designed to eliminate guesswork, build consistency, and help Boston professionals get strong safely.
The concept of First Guess Fitness was first conceived when Justin and Patrick were working together at another gym. Although we had a beautiful environment, great equipment and highly qualified coaches, we knew there was something else missing.
Clients still lacked clarity outside of the gym and there wasn't a sense of community that we know plays an integral part in keeping clients engaged and wanting more.
So we set up First Guess Fitness, first as an online learning platform that covered all the fundamental knowledge you needed to make real progress. We shared what we had learned about exercise, nutrition, mindset and accountability and set about going beyond the hour on the gym floor to helping people create more clarity, consistency and confidence.
As our success grew, we were presented with an opportunity to open up a physical space in downtown Boston and we snatched the opportunity to give First Guess Fitness a physical home and create a space where fitness is fun and the community is amazing.
Meet the Coaches
Patrick Jennings
Head Coach
Patrick is a strength and lifestyle coach who helps clients create lasting change by focusing on who they become — not just what they do. His philosophy is simple: where you are physically, mentally, and spiritually is a reflection of your thoughts, behaviors, and beliefs. If you want to change your life, you start by changing yourself. His journey into coaching began after college, living across the USA, France, and Australia. While working at a boutique fitness studio in Australia, he fell in love with helping people grow. That path led him back to the U.S., where he earned his Master's in Exercise Science and spent the next decade coaching in studios across the country before opening his own gym. Patrick approaches coaching with empathy, humor, and a genuine interest in every client's story. He believes self-belief is one of the most powerful — yet most overlooked — tools for transformation.
Rome
Strength & Conditioning Coach
Rome is a personal trainer and former collegiate athlete focusing on strength and conditioning, athletic performance, and functional fitness. His coaching style focuses on helping people move better, build strength, and become more confident in what their bodies can do. Whether working one-on-one or leading a group, Rome brings an energetic, supportive approach that challenges clients while meeting them at their individual fitness level.
Justin Kompf, PhD, CSCS
Behavior Change & Exercise Coach
Google Scholar profile →Justin has been coaching since 2009. From 2013 to 2017 he worked as a college strength coach while completing his master's in exercise science. Around that time he became more interested in behavior change, helping people who never exercised get started. So he moved to Boston in 2017 to begin his PhD. In 2021 he began a postdoc at Brandeis University but a little more than a year in he was asked to serve as the fitness director for a telemedicine weight loss clinic. That clinic was subsequently acquired by WeightWatchers. Justin had been personal training in Boston throughout his career there and when the opportunity to start a physical location came up he jumped at it! Justin focuses on the intersection of behavior change and exercise prescription. He believes everyone can become a consistent exerciser with the right support structures.
Scout 🐕
Chief Morale Officer
Scout doesn't really do much coaching. In fact, he is adamant that you give him treats. He mostly sleeps and appreciates belly rubs. Most members say he is their favorite coach.
Meet the Founder & Head Coach
Patrick Jennings
Founder & Head Coach
- Master's in Exercise Science
- Over a decade of coaching experience across the U.S. and Australia
- Co-founder of First Guess Fitness in Downtown Boston
- Expert in lifestyle change, habit building, and sustainable strength training
Featured In & Backed by Research
Justin's work and expertise have been featured in national publications and leading research organizations.
The First Guess Fitness Method
Progressive Resistance Training
Clear, progressive resistance training tailored to everyday adults — programmed around your body, your schedule, and your goals.
Habit Architecture
Habit architecture designed for busy schedules without burnout, built on behavioral psychology so consistency becomes automatic.
A Private Studio Space
Our private 30 Court Square studio means no crowds, no waiting for equipment, and coaching that's fully focused on you.
Experience Science-Backed Coaching in Boston
Train with a team founded on exercise science — and see what consistent, expert-guided strength training can do for you.
Looking for personal training in Boston? First Guess Fitness is a top-rated private fitness studio in Downtown Boston at 30 Court Square — offering 1:1 personal training, semi-private training, strength coaching, and online coaching.
Neighborhood pages: Back Bay · South End · Financial District · Beacon Hill · City Hall · Faneuil Hall · Government Center · Downtown Crossing · Pricing