How does forced breathing differ from quiet breathing and what muscles are being used?

Forced breathing, or active breathing, involves the use of additional muscles to increase the volume of air inhaled or exhaled, typically during vigorous activities or exercises. In contrast, quiet breathing, or passive breathing, relies primarily on the diaphragm and intercostal muscles, functioning without conscious effort. During forced inhalation, accessory muscles such as the sternocleidomastoid and scalene muscles are engaged, while forced exhalation may involve the abdominal muscles and internal intercostals to expel air more forcefully.