Getting Oxygen from the Atmosphere to the Muscles - Football Fitness

For any human to live, let alone function properly, the cells within their bodies require oxygen. Luckily for humans oxygen is present in the atmosphere around the Earth, however it is not the only gas present. 78% of the atmosphere is nitrogen, 21% oxygen, 0.9% argon and 0.03% carbon dioxide. These figures mean that 4/5th’s of the gas in the atmosphere is unusable by the human body. Therefore the body must separate them before the desired gas can be delivered to the cells. Once the oxygen is delivered to the cells it can be used to release energy for compulsory (heartbeat) and voluntary (walking / running) actions and movements.

The process the body undertakes to get the air into the body and separate in accordingly is known as breathing and is overseen and controlled by the respiratory system. The function of breathing can be split into two phases; inhaling and exhaling. During the inhaling phase the body brings air in, separates the oxygen and delivers it to the cells, while during the exhaling phase the used (now carbon dioxide) and unwanted (nitrogen) air is removed from the body. For the body to complete both phases of the breathing process the body requires 3 separate but related parts of the respiratory system; the air passages, the lungs and the diaphragm.

Air Passages

The air must get from the atmosphere to the lungs. In order to achieve this there must be a pathway it can take. Such a pathway does exist and is created by a number of linking tubes that run from the airs entry points (the mouth and nose) to the lungs. Tubes along the pathway are:
The larynx (voice box) – air passing over this produces the voice.
Trachea (windpipe) – which is the main path for the air to travel down. Cartilage rings keep the tube flexible and always open.
Bronchi – are the name given to the two smaller tubes the trachea is split into as it nears the lungs.
Bronchioles – finally the air passes though smaller tubes connected to the bronchi so that it can enter the lungs.

Air can be sucked into the body through either the nose or the mouth. Air that is brought into the body through the mouth tends to be cooler, dirtier and drier than that through the nose. This is because the nose has hairs and mucus within it that moistens the air, filters out the larger dust particles and warms the air so that it is of a similar temperature to the body temperature of the individual. Once the air is in the bronchioles it is now entering the lungs.

Lungs

The lungs are two large sac like organs within the chest region. They are constantly moving expanding and contracting due to the breathing process so are heavily protected by:
The pleural membrane - a smooth, moist, slimy lining that encases the lungs and prevents friction.
The ribs – Bones that form a cage around the lungs.
The intercostal muscles – Muscles in between the ribs to aid contracting and relaxing. The lungs are positioned at the bottom of the trachea and are comprised of millions of alveoli. The alveoli are the main components of the air exchange process. Each is covered in many capillaries, through the walls of the alveoli the new oxygen enters the bloodstream and the used air (carbon dioxide) is removed. The blood then delivers the newly oxygenated blood to the muscle cells through the circulatory system. If too much carbon dioxide is allowed to remain in the body then the result could be fatal.

The lungs (and the alveoli in particular) can be trained to complete the exchange more efficiently and effectively, this is achieved through regular exercise and training. This is because the lungs are forced to work at different capacities depending on the individuals activities.

If the individual is just resting and breathing normally the lungs will have a basic amount of air inside them, known as the Tidal volume. When exercise or an activity is undertaken the breathing is increased as more energy (and therefore oxygen) is required by the muscle cells. This increased amount of air is known as the Vital capacity. When the vital capacity is required, over a prolonged period of an exercise programme, more alveoli become involved in the exchange process, so that the body can supply the required oxygen. These alveoli are then still incorporated in the exchange process when resting, and therefore more alveoli completing the tasks mean less work completed by each one.

Even with the biggest exhale as possible the lungs will still not release all the air in them. Instead they retain approximately 3 litres to ensure they can operate properly. This remaining volume in the lungs is known as the residual volume.

Although the air is transported to the lungs by the airways and transferred into the blood through the lungs there is still one integral element to the breathing process and that is the diaphragm.

The Diaphragm

The lungs themselves are not a pair of muscles and can not move on their own. Therefore they are unable to generate the motion required to suck air through the airways into themselves. This process is the role of the diaphragm and the intercostal muscles.

When inhaling the diaphragm pulls downwards and the intercostals contract, (by contracting the ribs are pulled closer together). Both these movements result in the volume of the chest cavity increasing and the air pressure lowering, which in turn leads to the air from the atmosphere being sucked in through the mouth or nose, down the airways and into the lungs.

When exhaling the diaphragm returns to its usual dome position and the intercostals relax (allowing the rips to drift further apart). Therefore the opposite result to inhaling is achieved – the volume of the chest cavity decreases and the air is pushed or forced out of the body (through the same airways it came in). Once the air has been released the body will then inhale again.

Each of the 3 components outlined above are essential to the breathing process and getting the oxygen into the blood, as none can work in isolation. As a soccer coach it may not seem essential to have an understanding of this process, but this process is essential to performance and life. Therefore an appreciation and a basic understanding should be obtained so that players can be educated on the process.