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Description of How Exercise Affects the Muscles

Apr 24, 2011 | By Hannah Mich
Description of How Exercise Affects the Muscles
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Adaptations or changes in skeletal muscle after exercise have been observed and studied extensively, especially since the 1960s. These changes occur because of supply and demand -- the greater the demand, the stronger and more efficient your muscles. Muscle adaptations range from an increase in blood flow to hypertrophy or growth of your muscles. Strength and endurance training affect your slow-twitch and fast-twitch muscles differently as well.

Neuromuscular

The neuromuscular system is the interaction between your muscles and the nerves that innervate or control them. Repetitive exercise such as running stimulates the neuromuscular system, causing more individual muscle fibers to be activated and better timing of muscle contractions. This results in improved strength and coordination. Neuromuscular improvements occur early on in an exercise program, but can taper off without proper exercise progressions such as increasing resistances with strength training.

Hypertrophy

Strength training causes muscle growth or hypertrophy, especially when you exercise with high resistance and low repetition. When your muscles increase in size, your body is not building more muscle; instead, individual muscle fibers that make up your muscles are getting bigger in size. The University of New Mexico reports that muscle hypertrophy takes six to eight weeks, when you strength train two to three days a week. Furthermore, fast-twitch muscles increase in size more so than slow-twitch muscles.

Mitochondria

With endurance or aerobic training, muscles, especially slow-twitch, need oxygen to create energy. In each muscle cell is an organelle called a mitochondria that takes oxygen and uses it to make energy. Prolonged endurance training leads to an increase in mitochondria in muscle cells. More mitochondria mean an increase in oxygen uptake from your muscles' cells and more energy. With more energy, you can exercise harder and longer.

Blood Vessels

Exercise, both strength and aerobic training, increase blood flow to your muscles. Increased blood flow gets nutrients and waste to and from your muscles quickly, allowing them to function more efficiently. Prolonged training increases the number of capillaries supplying blood flow to your muscles, therefore further increasing blood flow and improving muscle function.

Glucose

During exercise you use or contract your muscles constantly, which increases the transportation of sugar or glucose in your bloodstream to your muscles and other organs for energy. This increase in glucose uptake in your muscles during exercise also replenishes your muscles' fuel or glycogen stores more quickly after exercise. Exercise, therefore, increases your muscles' energy output during exercise and helps your muscles recover faster after exercise.

References

Article reviewed by demand68117 Last updated on: Apr 24, 2011

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