Breathing Mechanics

Inspiration & Expiration

The diaphragm and external intercostal muscles contract. The external intercostal muscles raise the ribs upwards and outwards. This increases the volume of the chest cavity and causes air to rush into the lungs

The diaphragm and external intercostal muscles relax, the internal intercostals contract. this lowers the ribs downwards and inwards. This decreases the volume of the chest cavity and causes the air to be forced out the lungs

Inhaling and Exhaling During Exercise

During inspiration The pectorals and sternocleidomastoid muscles raise the sternum allowing the lungs to expand further

During expiration The rib cage is pulled down quickly due to the contraction of the abdominal muscles