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).
Certain trunk and core muscles participate in the breathing process, as well. You might say they do double-duty as both posture and breathing support. These most important of these muscles are: The diaphragm muscle, which is the principal muscle of breathing, contracts in order to take air into the lungs, and it relaxes in order to let it out again. When the diaphragm contracts, it moves down from the bottom of your rib cage towards your abdominal region.