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  • Running Coaching and Training

  • TRX and Body Weight Exercises

  • Functional Training

  • Injury Prevention


With over a decade of experience working with clients ranging from Olympians to first time exercisers, from mountain climbers to those recovering from severe stroke, Sean has a strong desire to improve the lives and health of every client he works with. 

Energy and persistence conquer all things.
— Ben Franklin

He believes that achieving good health is a multi-faceted process, with exercise, nutrition, recovery and most importantly mental attitude all working together in harmony. Because of this, every client he works with receives a comprehensive assessment covering all aspects of health including body measurements, structural issues, muscle imbalances, nutrition/sleep/stress questionnaires, core strength, and movement patterns. He then uses this information to construct a personalized, all-encompassing health plan that includes strength training, cardio, nutrition, stress relief, and recovery and is dedicated to initiating change. One of his favorite things in the world is when a client tells him that he has changed their life in a dramatic and positive way.

Sean graduated from American University in Washington DC with a Bachelors of Science in Health Promotion and a Masters of Science in Health Promotion Management.  He maintains two of the top training certifications, NSCA-CSCS and NASM-CPT and additionally is certified for TRX suspension and TRX Group. His education is fundamental to his approach as a trainer. Sean believes training and coaching is both an art and a science and draws heavily from all the great teachers he has had throughout the years.

He learned early in life the benefits of hard work. Growing up in New Hampshire he was a 4X state champion in Track and Field and a 2X state runner-up in Wrestling, finishing 4th at the New England Wrestling Championships his senior year. In College he was a 4X Division 1 All-American at AU, finishing 4th at the NCAA Championships 1500m. While working on his graduate degree he was also the Assistant Coach of both the Men’s and Women’s Track and Field and Cross Country teams. In this position he was in charge of middle distance development and strength training for the entire program.  After finishing his education he was recruited by legendary running Coach Frank Gagliano to join the Nike Farm Team, a pro team training for the Olympics out of Stanford University. Eventually the team moved to Eugene Oregon and became the Nike Oregon Track Club Elite.  Running for Nike he competed in the 2004 US Olympic Trials in the 1500m, making the semi-finals. He represented the USA at the 2006 Penn Relays DMR USA vs The World, anchoring the team to a second place finish behind Team Kenya.  The same year he was 3rd at the USA Indoor National Championships in the 1500m. He is a sub-four minute miler with a personal record of 3:58 and a 1500m PR of 3:38. He was the 273 American runner ever to break the four minute barrier.

After retiring from competitive running Sean focused his energy on another great love of his, training and coaching others.  For his own personal exercise he switched to Rock Climbing and has climbed at locations all over the world. Including classic spots like Yosemite and Fontainebleau France, and from the mountains of Peru and Nepal to the beaches of Tonsai Thailand and Rio de Janiero. He also enjoys parkour and competed on the TV show American Ninja Warrior, successfully navigating the course without falling but ironically failing to advance on time. He has recently relocated to San Francisco from Washington DC, where he worked out of Mint health club, of which he was also the Fitness Director.

Sean's clients include:

  • Olympians: Track and Field

  • First Time Exercisers

  • Advanced Level Mountaineers and Climbers

  • Post-Rehab Clients

  • Weight Loss

Sean has been lucky enough to work with many great clients and hopes that you will be the next!


  • National Strength and Conditioning Association | Certified Strength and Conditioning Specialist

  • National Academy of Sports Medicine | Certified Personal Trainer

  • TRX Suspension Training

  • TRX Group Training

  • National Academy of Sports Medicine Performance Enhancement Specialist

  • American University | Master of Science in Health Promotion Management

  • American University | Bachelor of Science in Heath Promotion


Sean O’Brien is an exceptional athlete turned trainer who understands the needs and demands of a professional, but has the knowledge, desire, and passion to work with individuals of all levels, ages, and abilities. He is creative, meticulous, and delivers an attainable, yet highly challenging workout. Sean has an excellent understanding of the human body and is committed to educating his clients while simultaneously motivating them through each individual exercise. He has traveled across the globe and brings a wealth of knowledge of different practices into his client’s routines. He mentored me both physically and emotionally through injury and I returned to the track faster than when I left. He is the most dedicated, attentive, and devoted trainer I’ve ever worked with.
— Julie, 2012 US Olympian 5000M
Sean was incredibly patient and never gave up on me; with his encouragement, I eventually started to see results and grew excited about the potential for change. I lost a substantial amount of weight and dropped 3 dress sizes. But even more importantly, my confidence and interest in health and fitness have improved immeasurably. Sean varies my training sessions enough to keep me interested and motivated. He’s also very good at modifying exercises for my body’s limitations (Including an ankle injury that I’ve had for years), while keeping them challenging and improving those weaknesses. Rather than focusing on quick weight loss, Sean has taught me to focus on my overall health, including strength training, core strength, and flexibility. As a result, I’ve noticed substantial improvement in all of those areas and my outlook on health and fitness has never been better.
— Terri