Staff & Expert Contributors

“Creating champion athletes through the application of sport science, expert collaboration, and the ruthless pursuit of excellence.”

Jesse Rodriguez

Jesse is a Registered Dietitian with experience in clinical nutrition, sports dietetics, and entrepreneurship . He holds a Bachelor’s of Science in Nutritional Science with the addition of a CSCS certification from the NSCA. Jesse swam for the El Salvador National Team and competed at the international level. Before beginning his profession, Jesse has interned at USC with the Strength and Conditioning program and UCLA as the lead intern for Sports Nutrition. As part of the Ruthless Performance team, Jesse provides nutrition consulting to variety of clients in effort to to promote health and help reach clients goals. During his free time, Jesse enjoys reading, swimming, strength training and staying up-to-date on the latest nutrition research. Lastly, Jesse is a member of the Academy of Nutrition & Dietetics, National Strength and Conditioning Association, and Collegiate & Professional Sports Dietitians Association.


John Matulevich

John is the owner of Ruthless Performance. Previously, John was a collegiate Strength & Conditioning Coach (NCAA D2) and record-holding powerlifter (4 WR’s/ 9 SR’s – RPS). John specializes in sports performance, exercise physiology, and injury prevention. He is regularly featured in various print and online publications including EliteFTS, Stack Media, and Muscle & Strength. John is the Strength & Conditioning expert contributor to Swimming Science where he works to bridge the gap between the fields of coaching and kinesiology. Through Ruthless Performance, John consults for various businesses, teams, and individuals ranging from adolescent through the professional level. John is also active in health policy, business administration, and throughout his local community.