During times of forced breathing what muscles join in to aid respiratory effort?

During forced breathing, the accessory muscles of respiration become active to assist the primary muscles. These include the sternocleidomastoid and scalene muscles in the neck, which help elevate the rib cage, as well as the pectoralis major and minor muscles in the chest. The abdominal muscles also engage during forced exhalation to help push air out of the lungs more effectively. This coordinated effort increases the volume of air exchanged during vigorous activities or respiratory distress.