Dr. Sarah Sarkis is a licensed psychologist, certified executive coach, and the Senior Director of Performance Psychology at Exos. At times you’ll also find her moonlighting as a writer and podcaster. With over 20 years of experience, she has had the opportunity to explore every corner of the human psyche, helping her to guide individuals to new personal heights. Currently, she’s applying her passion, expertise, and focus to helping CEOs, athletes, professional coaches, and other executives achieve moonshot dreams and soar past goals. Part shrink, part coach, part Jedi of the unconscious, Dr. Sarkis leverages her knowledge, experience, and insight as a leader within the Exos Performance Innovation Team.
Dr. Chris Bertram is an experienced applied neuroscientist and human performance coach with over 20 years of experience and expertise. He guides top entrepreneurs, executives, and athletes on maximizing learning, building resilience, and optimizing performance under pressure. As the Senior Director of Applied Neuroscience at Exos, Dr. Bertram leverages his work with high-consequence athletes into data-driven performance strategies for business professionals. He’s also been known to write here and there, with over 70 scientific publications across the spectrum of human performance, featured in The Globe and The Mail, The Toronto Star, The Vancouver Sun, The New York Times, Inc. Magazine, and on the Golf Channel. Recently, Dr. Bertram even authored a book chapter on "Flow State as a Countermeasure to Mental Fatigue" and is featured in the documentary "FLOW." His role at Exos and broader impact make him a driving force in maximizing human performance.
Over the last eleven years, Michelle has dedicated most of her career to partnering with top executives and rising leaders at Fortune 100 companies to tap into their optimal performance. Additionally, Michelle has supported celebrities and executives from around the world as they actualized their wellness journey and worked toward overcoming obstacles, such as anxiety and addiction, at a world-renowned treatment facility.
Michelle is passionate about coaching from a holistic mind-body perspective in order to cultivate sustainable high performance in her clients. Since beginning work with Exos in 2015, Michelle has piloted and led Exos’ Mindset Series, managed and mentored internal and external teams, and supported various professional resilience projects. Michelle’s propensity to lead and connect to those around her has allowed her to work with an array of individuals. With that said, her true strength lies in her ability to meet people where they are and help them towards their goals
Michelle obtained her bachelor’s degree in health promotion and nutrition with an emphasis on stress management, as well as a master’s degree in health promotion and exercise science. She is a Mindfulness Coaching School trained group coach, a certified yoga and Pilates instructor, a NASM (National Academy of Sports Medicine) certified trainer, and an Advanced Les Mills group fitness trainer and coach.
Stefan Underwood is a highly accomplished performance specialist and Senior Vice President of Methodology at Exos, bringing with him nearly two decades of experience in human performance. His passion is helping individuals excel, and he’s known for his expertise in working with elite tactical and NFL combine prep populations. These days you’ll find him applying his knowledge to the business world and sharing his insights globally as a presenter in Exos Education.Stefan leads his diverse team of experts in neuroscience, psychology, coaching, dietetics, and sports science, fostering collaboration through his empathetic leadership style. If that wasn’t enough, Stefan is also currently pursuing a graduate degree in organizational psychology. From his broad competency and ability to inspire high-performance individuals and teams to his unwavering dedication to unlocking optimal human performance, Stefan is always pushing for more within the Exos Performance Innovation Team.
Sloan is an experienced mental skills coach who has supported a wide range of populations, including youth, high school, and collegiate student-athletes. Sloan has developed tailored mindset curriculums for teams, coaches, and parents in addition to coaching individuals through their own tailored weekly mental performance sessions.
Sloan is passionate about using psychology and experiential learning to develop mental strength and resiliency not only in athletic performance but also within professional and family life. She is eager to build relationships that empower others towards achieving their goals, living their values, and strengthening their growth mindset.
Sloan holds a master’s degree in applied sport and exercise psychology from the University of North Carolina Greensboro and a bachelor’s degree in exercise and sport science from the University of North Carolina at Chapel Hill. Additionally, she holds a UNC Business Essentials Certificate through UNC Kenan-Flagler Business School and is a Certified Mental Performance Consultant through the Association for Applied Sport Psychology.
For more than a decade, Dai has supported high-performing teams and individuals in the United Kingdom, Germany, and the United States. He has coached everyone from emerging leaders at Google, Adidas, and the U.K.’s most prestigious multinational law firms to top athletes in the English Football Association and the Premier League’s Elite Player Performance Plan.
Dai’s signature strength is his ability to help the broader population cultivate resilience and adaptability in the workplace. He does so by translating the core principles of human performance and guiding emerging leaders on a path toward sustainable behavioral changes, in turn helping emerging leaders understand how and what it takes to actualize their potential — regardless of age, experience, or genetic capabilities.
Amanda leads the Exos performance innovation team bringing the most cutting edge solutions to Exos clients and helping to pioneer the industry of human performance for almost 20 years.
Amanda joined Exos in 2003 and holds a Master’s Degree in both sports/clinical nutrition and exercise physiology. She has worked with professional, elite and youth athletes across elite sports, professional and collegiate sports teams, military operators and forward thinking organizations to optimize their human performance systems.
Amanda speaks nationally about the importance of improving nutrition for performance and overall health but is known as a leader beyond nutrition and more broadly about how to bring an integrated high performance program to life. She has contributed to many sports and fitness based publications, has edited various sports nutrition books and educational texts, and now serves as an ambassador to the Collegiate and Professional Sports Dietitians Association after serving on their Board of Directors for six years.
With Exos since 2020, Greg Hill is the company’s chief people officer. By advocating for and supporting the development of Exos team members, he leads people operations, talent acquisition, and culture development. Exos’s culture has been recognized as a certified Great Places to Work and Best Employer in Sports by Front Office Sports.
His 30 years of experience includes leading people and workforce strategies for Equinox, SoulCycle, Starwood (Sheraton, St Regis, W Hotels, Westin) and Hyatt Hotels. He is the former chairman of the American Hotel & Lodging Association’s Labor Council and has a B.S. in Human Resources from Niagara University.
One of the world’s foremost experts on performance, Mark is the founder and president of Exos. In his role he focuses on elevating performance globally, overseeing the continual Exos evolution to raise up all of the company’s clients. He’s a global keynote speaker and the author of six books and numerous research articles.
His 30 years of experience includes being the founder and president of IMG Academy’s International Performance Institute and serving as a performance and nutrition coach for Washington State University, University of Idaho, and Georgia Tech. Mark has also served as the performance director of the NFL Players Association for 22 years.
John is a Senior Vice President that leads the team responsible for the training and continuous improvement of the coaches and practitioners at Exos. Coaching for over 20 years, he joined Exos in 2006 and has supported professional athletes, tactical personnel, performance practitioners, and youth athletes from around the world. He has had the opportunity to lead multiple teams and projects over his 18 years with Exos but his team's responsibility; the training and developing coaches and practitioners, is the most important and fulfilling.
Leron has 10 years of experience as a sports dietitian. Through her career, she has worked with military special operations, professional athletes, and consulted for pro sports teams. Leron also spent four seasons as the Director of Performance Nutrition for the San Francisco Giants. She believes that optimal nutrition — achieved achieved through balance, simplicity, and sustainability — is pivotal to performance, whether you’re a professional athlete, Navy SEAL, or high-performing executive.
Dr. Michael Duffy Jr. joined Exos in 2024 as a Mental Performance Coach, committed to helping high-achieving individuals and teams win at work. With over a decade of experience applying evidence-based coaching psychology and positive organizational behavior, Michael brings the science of wellbeing into organizations to enhance resilience, engagement, performance, and team culture through personalized 1:1 coaching, dynamic group facilitation, and tailored programs. He specializes in cultivating mindsets and systems that empower individuals to perform at their best while fostering cohesive and thriving workplace cultures.
Before joining Exos, Michael founded and launched a successful wellness venture, blending his passion for health with his expertise in human performance. He later earned a Master’s in Applied Positive Psychology and Coaching from the University of East London, followed by a PhD in Work Psychology from Sheffield University Management School. An active speaker and thought leader, Michael presents at national and international conferences, delivers guest lectures, and co-authors articles for academic and industry audiences. Whether delivering keynote speeches, conducting research, coaching individuals, or collaborating with organizations, Michael is driven by a commitment to excellence, innovation, and meaningful change.
Brent Callaway is Exos’ Vice President of Sports Performance. With over 15 years of coaching elite athletes on the intricacies of human performance across a broad spectrum of sports, he is responsible for their NFL Combine prep program, NFL/MLB/NBA off-season programs, and their NBA pre-draft program. He also oversees performance staff and programming for all of Exos’ international assignments which has included the Chinese Olympic committee, Athletico Paranaense Football Club, the Shanghai Research Institute for Sport Science, Los Angeles Galaxy Football Club and the Portland Timbers.
Eric’s fast-paced, dynamic coaching style is grounded in his Northeast roots. He believes in making the most of every moment, whether it’s shaving seconds off a PR or maximizing the benefits of a short workout. With over 17 years of experience, Eric has coached professional athletes in the PGA, NHL, NBA, NFL, and UFC as well as youth and tactical populations. His expertise spans strength, speed, yoga, Pilates, rehab, mindset, and nutrition.
Karla is a registered dietitian and a certified specialist in sports dietetics who began her career as the sports dietitian for the Arizona State University athletic department, where she supported over 500 student athletes, 21 teams and contributed to two Women's Softball NCAA Championships. Karla believes in the power of personalized care, inspired by her favorite Mark Verstegen quote: "You don't have to be a professional athlete to be treated like one."
What began as an athletic career evolved into a career of helping others find their fire and be leaders in their own unique environments. Kersten - a former professional basketball player with a Masters concentrated on psychophysiology - is passionate about finding the levers that make each individual’s top performance sustainable and creating a whole life that supports what matters most.
