Aerobic Muscles

In the human body, most muscles are made of a combination of aerobic and anaerobic fibers (the exceptions are some of the jaw muscles that are all anaerobic). The aerobic fibers are uniquely different from their anaerobic counterparts. Aerobic fibers are sometimes called “red” because they contain structures called mitochondria, which contains the iron-protein, red-pigmented compound myoglobin. It is here, through myoglobin’s action in the mitochondria, that oxygen is successfully used in the energy-generating process. The more these muscles are trained, the more mitochondria and myoglobin is produced, and the more oxygen will be utilized to help produce energy. The fuel for the mitochondria’s powerful endurance energy is fat.

Also unique to the aerobic muscle fiber is that it is generally fatigue-resistant. This is because the availability of fat for energy is quite vast even in lean athletes. Over time, aerobic muscle fatigue is due to the brain and metabolic aspects. Even after ten hours of racing, there can still be unused glycogen in the anaerobic fibers—unless you used it inadvertently during the event (often the result of too high an effort such as running too fast at the start of a marathon). If this small reserve is still intact, it is quite useful for your final effort, and, even more important is that it helps maintains a relatively high amount of fat burning throughout your training and competitive period.

广告：个人专属 VPN，独立 IP，无限流量，多机房切换，还可以屏蔽广告和恶意软件，每月最低仅 5 美元

Another important characteristic of the aerobic fiber is its high concentration of blood vessels, which contributes to its red appearance. Blood coming into the fiber brings oxygen and nutrients, including vitamins, minerals, and fats. On its way out, blood carries away by-products such as carbon dioxide and lactate.

Aerobic muscle fibers are also home to important immune system functions, specifically, that of controlling chemical free radicals through antioxidant activity. (In order for this to happen, antioxidant nutrients must be provided by the diet.) Athletes who are often ill with colds, flu, and other indications of poor immune function typically also have reduced aerobic function.

The aerobic fibers are the most commonly contracted part of a muscle, even in everyday action. Your physical activity at work and home, and doing everyday chores requires aerobic muscle activity. They are also the muscles that support the body’s joints, bones, and other areas to help prevent and correct injuries.