David Barr, CSCS, has been involved in the field of strength and conditioning for more than two decades, working with athletes ranging from young children to NHL players later inducted into the Hockey Hall of Fame.

His research background includes work for NASA at the Johnson Space Center as well as clinical research on the effect of protein and amino acid supplements on muscle growth and recovery. He has also gleaned unique insight from his time working for the American College of Sports Medicine (ACSM) and the National Strength and Conditioning Association (NSCA), where he was an instructor for the top-tier certification, the Certified Strength and Conditioning Specialist (CSCS).

Barr has published peer-reviewed research as well as dozens of print and online articles for Bodybuilding.com, T Nation, Elite FTS, and others. He has also published four books and four textbook chapters, including the protein chapter of NSCA's Guide to Sport and Exercise Nutrition, Second Edition. He served as a technical advisor for Muscle & Fitness magazine, where he provided insider tips and tricks from the fitness models, bodybuilders, and figure competitors he worked with.

Barr is currently a master instructor for Pain-Free Performance Specialist Certification (PPSC), which allows him to travel the world helping personal trainers and strength coaches achieve lifelong pain-free performance.