Introduction

Every time an athlete trains or competes, the body responds as one coordinated machine: muscles contract, the heart beats faster, breathing deepens and stored fuel is released to power the effort. The branch of study that explains these responses is exercise physiology — the study of how the human body reacts and adapts to physical activity. This chapter of the CBSE Class 12 Physical Education syllabus looks first at how a fit body works, and then at what happens when that machinery is damaged on the field.

In the sections that follow you will study the physiological factors that decide the components of physical fitness, the short- and long-term effects of exercise on the muscular system and on the cardio-respiratory system, the physiological changes the body undergoes with ageing, and finally the classification, types and management of common sports injuries. Understanding this material is useful well beyond the CBSE Class 12 Physical Education exam: it explains both why training improves performance and how knowledge of the body helps an athlete prevent and recover from injury.