Dive into the fascinating world of medical exercise therapy, where science and movement intersect to reveal the secrets of our muscular system. Starting with a gripping introduction to evidence-based exercise therapy, this chapter navigates through the complex anatomy and vital functions of the skeletal muscle. Learn how muscle and fat mass influence body weight and discover the diversity and uniqueness of muscle types. With a deep dive into muscle physiology, a window opens to the world of the sensorimotor system, the processes of muscle contraction, and the vital energy provision processes that drive our movements. Be fascinated by the workings of muscle spindles, Golgi tendon organs, and other key receptors that make our myofascial system a marvel of nature. Explore the differences between muscle fiber types and their specific roles in our body. Deepen your understanding of the various forms of muscle work and how they shape our physical performance. Immerse yourself in the world of training-related biomechanics, explore the essence of torque in strength training, and learn how biomechanical principles can help you avoid injuries and achieve your training goals more efficiently. In conclusion, the difference between the open and closed system in training is discussed, an essential aspect for optimizing your training routine. This chapter promises not only a profound understanding of the basics of medical exercise therapy but also exciting insights that will revolutionize your perspective on movement and health. Get ready to expand your knowledge and elevate your training practice to the next level.