Executive Team


Glenn Seth

RKC, WKC, LMT: Owner, Master Trainer

Glenn has been training with kettlebells for more than fifteen years after serving as a US Marine, and has certifications from World Kettlebell Club (WKC), Russian Kettlebell Challenge (RKC) and ACE. He has trained with world-class athletes Valery Fedorenko and Catherine Imes. Glenn's unique teaching approach to kettlebell training focuses on flow which, along with fitness and function, give F3 its name. At F3 Training and Bodywork, rated best kettlebell workout by the Washington Post, Glenn and his team offer a progression program for new clients to advance their kettlebell practice through four stages, called the Path of the Warrior. For advanced students and local trainers, Glenn offers DC's only kettlebell certification program, The VonSeth Method. He is also a licensed massage therapist with over fifteen years of hands-on training and experience in top spas in and around DC.


Sarah Seth

MBA, HKC: Business Manager

Sarah was born in Paris but grew up in Cote D’Ivoire (her country of origin) and France until moving to the USA in 2008 to continue her studies. She became a strong advocate for fitness and wellness after she decided to adopt a healthier lifestyle six years ago, which resulted in a significant weight loss and drastic improvement in her health and wellbeing. Sarah was introduced to kettlebell training and the health and wellness industry by her husband Glenn in 2013 and it automatically turned into her passion. Having witnessed the life-changing effects of kettlebell training, she was inspired to use her business management background to assist her husband in growing their family business and sharing the tremendous mental and physical benefits of fitness training and massage therapy with their community. Sarah holds a bachelor’s degree in Business Administration from Temple University and a Master of Business Administration from University of Maryland University College. She is also a Hardstyle Kettlebell Certified (HKC) Instructor. She loves traveling and discovering new cultures with her family and is dedicated to raising a healthy, happy daughter.


Kettlebell Training


Jenny Harlett

HKC: Head Trainer

Jenny came to F3 after finding herself bored and frustrated with lack of results at the gym. That was more than five years ago, and she has never looked back. After seeing the detrimental effects of a non-active lifestyle in the health of loved ones, Jenny has become a huge proponent for helping women (and men!) build muscle strength and maintain physical and mental health throughout their lives. After working with Glenn Seth for more than two years, she jumped at the chance to become a certified F3 coach in February of 2014. She is also a HardStyle Kettlebell Certified Instructor. When she is not slinging bells and coming up with new workouts, Jenny can be found writing, traveling, and seeking out pinball games.


Coach Danny Lamas

B.A, HKC: Trainer

Danny is a certified F3 coach and Hardstyle Kettlebell Instructor. He has trained under Master Trainer Glenn Seth since 2011. He has a B.A. from George Washington University in Political Science. He was inspired to take up kettlebells as an enthusiast of author Tim Ferriss’s books on entrepreneurship, learning, and fitness. The efficiency of full-body kettlebell workouts in improving functional strength and producing rapid fat loss inspired him to become a regular at F3 for more than two years before becoming an instructor. Danny enjoys presenting clients with new and exciting challenge through consistently varied workouts.


Coach Katy Hospital

HKC: Trainer

Katy came to F3 in July of 2013, with no weight lifting experience and arms that bore a striking similarity to those of a T-Rex. A year and a half later, Katy is now a firm believer in F3 and master trainer Glenn Seth’s approach to building strength and wellness safely in a supportive environment. Katy credits kettlebell training with her improved strength, flexibility, and cardio health and has been a certified F3 coach for over a year. She also recently became a Hardstyle Kettlebell Certified Instructor.


Massage & Yoga


Lauren Newmyer


Lauren loves helping people find a deeper sense of mind/body harmony through thoughtful, personalized Bodywork and yoga sessions. Her massage style encourages a deep sense of relaxation while targeting specific muscles to effect lasting change and restore balance in the body. Her work draws upon her studies in traditional Thai massage, active isolated stretching, and myofascial release. Her yoga sessions are informed by her extensive knowledge of anatomy, and inspired by the latest trends in the growing field of yoga therapy. Lauren is a graduate of the New School for Massage Bodywork and Healing, and Willow Street Yoga Center's teacher training program.