Before thinking about which exercises, frequency and intensity should be used in strength training programs to achieve muscle strength, promote a healthy lifestyle, hypertrophy or improve athletic performance, we should understand firstly how a muscle contraction happens. The aim of this book is to provide you with a basic to advanced understanding about several physiological systems involved in muscle contraction: physiological adaptations for exercises, especially strength exercises; molecular responses; methods of training; nutrition and muscle performance; muscle recovery; benefits of strength exercises to human health; and which drugs are commonly used for doping in different sports. Chapter One of this book will review all of the most important cells, structures and processes involved in muscle contraction, such as neurons cells, synapses, motor units, general and molecular mechanisms of muscle contraction. Chapter Two will describe the most important bioenergetics pathways of energy supplies required for muscle contraction. After understanding how muscle contraction happens and how energy is supplied, the reader will discover principles, methods and physiological adaptations of skeletal muscles to strength trainings within Chapters Three, Four and Five. In particular, Chapter Four will provide a friendly and detailed account of molecular adaptation in skeletal muscles to different exercises, discussing differential gene expression and the effects of different exercises in different populations and disorders. This book also points out a very important and detailed factor concerning cryotherapy in Chapter Six, one of most common strategies used to promote muscle recovery. Specific orientations regarding nutrition and muscle performance are presented in Chapter Seven, while doping and different drugs used to increase muscle performance in several sports introduce Chapter Eight. Finally, Chapter Nine describes the benefits of strength training to diabetic, hypertensive, obese and myopathic patients. We strongly believe that all knowledge within this book is essential for all professionals working to promote the health of patients and increase physical performance of athletes or their clients, as well as for all people linked to sports and physical activity in some way.

Muscle function has been used to measure the healthy and functional capacity of patients, sportsmen and athletes. The knowledge about muscle function and how to properly evaluate it can be determinant factors for the success of therapies during the treatment of many diseases, as well as improving muscle performance. Handgrip strength is a measure of maximum voluntary force of the hand. It has been reliable, valid and an objective parameter to evaluate overall muscular strength, and for this reason, it has been used as a predictor of physical disability. There are several techniques to treat and rehabilitate muscle function such as the proprioceptive neuromuscular facilitation technique (PNF), functional training and traditional muscular strengthening. Physical exercises produce unquestionable health benefits, and when used properly, physical exercise can treat or become an adjuvant therapy for many diseases such as cancer, diabetes mellitus and patients with chronic heart failure. In addition to all the health benefits of exercise, new techniques of rehabilitation and the improvement of muscle performance were included in this book through the use of muscle strengthening associated to technological therapies, such as phototherapy (laser and light-emitting diodes), for muscle repair and performance. During your reading, this book will provide you with concepts, techniques and new perspectives about physical exercises that will become differential knowledge for health professionals to treat patients and/or make champions using powerful tools: physical exercise and technology.