Sports and exercise physiology is the scientific study of how the body's systems (like the cardiovascular, respiratory, and muscular systems) respond to and adapt to physical stress from exercise and sports. It's about understanding both the immediate (acute) and long-term (chronic) effects of physical activity to improve human health, physical fitness, athletic performance, and to aid in rehabilitation for injuries and health conditions. 

Focuses on the fundamental physiological responses to exercise, serving as the foundation for understanding human physical capabilities and adaptations to different types of physical stress. This is the application of exercise physiology principles specifically to optimize athletic training, enhance sports performance, and guide preparation for competition.