This section explains the respiratory system and the mechanism of breathing. The respiratory system has the ability to remove oxygen (O2) and carbon dioxide (CO2) that the body needs both at rest and during intense exercise. Breathing is the process of overcoming the forces encountered during inspiration (the elastic structure of the lungs and chest and airway resistance) through the body’s responses. While breathing is a passive process during expiration, it is an active process during inspiration. The skeletal muscles are designed to create movement in response to movement. However, this is not the case with the respiratory muscles. Respiratory system muscles are highly effective in resisting forces and overcoming elastic loads. Stretching is the process of elongating muscle fibers by mobilizing connective tissue. Having a strong respiratory mechanism depends on chest mobility, sufficient and healthy respiratory muscles that can create lung volumes, and the ability to move for adequate pulmonary ventilation. The purpose of this study is to explain the respiratory system and the stretching mechanism.