Book excerpt: Structure and Function of Exercising Muscle -- Fuel for Exercise : Bioenergetics and Muscle Metabolism -- Neural Control of Exercising Muscle -- Hormonal Control During Exercise -- Energy Expenditure -- Fatigue, Muscle Soreness, and Muscle Cramps Fatigue and Its Causes -- The Cardiovascular System and Its Control -- The Respiratory System and Its Regulation -- Cardiorespiratory Responses to Acute Exercise -- Principles of Exercise Training -- Adaptations to Resistance Training -- Adaptations to Aerobic and Anaerobic Training -- Prescription of Exercise for Health and Fitness -- Exercise in Hot and Cold Environments -- Altitude, Hyperbaric Environments, and Microgravity -- Training for Sport -- Nutrition, Body Composition, and Obesity -- Ergogenic Aids in Sport -- Children and Adolescents in Sport and Exercise -- Aging in Sport and Exercise -- Sex Differences in Sport and Exercise -- Cardiovascular Disease and Physical Activity.