You can elect to use a 52-53-week tax year if you keep your books and records and report your income and expenses on that basis. If you make this election, your 52-53-week tax year must always end on the same day of the week.
Forced Inhalation. Involved in the mechanics of breathing; The muscles involved in this type of breathing are the diaphragm, the external intercostal muscles, and the accessory respiratory muscles (activated when respiration increases significantly).
When the diaphragm muscle contracts, it pulls the bottom of the lungs downward, causing them to fill, while the ribs flare outward to the sides. The chest and abdominal muscles are not used in diaphragmatic breathing.