American College of Sports Medicine 
ACSM’s Foundations of Strength Training and Conditioning [PDF ebook] 

Developed by the American College of Sports Medicine, this text offers a comprehensive introduction to the basics of strength training and conditioning based on the latest research findings. ACSM’s Foundations of Strength Training and Conditioning is divided into four parts: Foundations, Physiological Responses and Adaptations, Strength Training and Conditioning Program Design, and Assessment. The text focuses on practical applications, enabling students to develop, implement, and assess the results of training programs that are designed to optimize strength, power, and athletic performance. Moreover, the text’s clear, straightforward writing style makes it easy to grasp new concepts.