Exercise PrescriptionExRx.net began in 1999 as a resource for exercise professionals, coaches, and fitness enthusiasts. Our online content, tools, products, and services are used and endorsed by universities and schools, government and law enforcement agencies, medical institutions, and private organizations and providers, as well as individuals seeking science-based exercise information and practical fitness assessment and exercise prescription tools. Our site features comprehensive exercise libraries (over 2000 exercises), fitness assessment calculators, and reference articles.