This text, in its second edition, integrates biomechanics and neurophysiology to provide a theoretical framework for the study of human movement. In this edition the research has been updated and the topics expanded to include a wider range of applications. Nearly twice the size of the first edition, the book features a broader scope, an expanded and updated reference list, more study questions at the end of each chapter, and more than 500 figures and tables. The first part examines the physics of the interaction between the moving body and its environment. The second part introduces the single- joint system and helps students translate their knowledge about force and motion to a biological model. The third and final part extends the single-joint system model for a complete account of human movement.