Your Muscles and Their Functions

Mrs. Stec- Physical Education

Types of Muscles

Any movement depends on a specific muscle. Each of these muscles are grouped in a category. There are three different category, which depend on its function.

Cardiac Muscle: striated tissue what forms the walls of your heart. The heart is the most important muscle in your body. Without it, well, you wouldn't be moving too fast! A cool fact is, your heart contacts 100,00 times a day! These contractions are done involuntary.

Smooth Muscle: responsible for movements of the internal organs-intestines,lungs, and bladder. These are also done involuntary.

Skeletal Muscles: attached to bones, there are more than 600 of these muscles. These muscles are voluntary, which means you control them. Check out the picture below for the major skeletal muscles.

                      Resistance training has little effect on involuntary muscles.

Skeletal Muscles

Two-thirds of the muscle you have are skeletal and they account for 40% of your body weight! Skeletal muscles work together to produce two actions, these are called contraction, the shortening of a muscle and extension, the stretching of a muscle. Right now, make a muscle! You should have seen this action when you did that. When you flex, you see a bulge, which is caused by a contraction. When you release, you then shorten the muscle and is now extending.

Types of Contractions

Dynamic- a type of muscle contraction that occurs when the resistance force is movable, such as a weight. This contraction has two phases a concentric phase, which is shortening, and then a eccentric phase, which is the muscles being released and becoming longer.

Example: Armcurls with a dumbbell are an example of an exercise that uses dynamic muscle contraction.

Static- a type of muscle contraction that occurs absent of any significant movement. So, flexing your arm is considered static.

Example: Pushing against a wall or other immovable object.

For a muscle to contract, it must receive a signal from the brain. This signal is carried by nerves, which are pathways that deliver messages from the brain to other body parts. The muscle fiber is the specific structure in the muscle that receives this signal.

Skeletal muscles are connected to the bones by fibrous cords of tissue called tendons. These bind the two together allowing the muscles to move efficiently. Bones are connected to one another by bands of tissue called ligaments.

How do my Muscles Grow?

Scientists do not fully understand exactly how and why resistance training builds muscles. However, several theories...

Muscle Hyperplasia- an increase in the number of muscle fibers, due to weight training.

Muscle Hypertrophy- a thickening of existing muscle fibers,not to an increase in their number. Researchers say that a person is born with his/her full number of muscle fibers. During resistance training, chemical and physical changes occur inside the muscle fiber that can cause hypertrophy.

Usually the goal of resistance-training is to increase your strength. With training and a healthy lifestyle, can and will improve your muscle strength. But, there are other factors, which include heredity, muscle size, and nerve function.

Heredity, is the total of physical and mental traits that you inherit from your biological parents.

Muscle Size, the larger the muscle, the greater its potential for strength.

Nerve Function, before a muscle can contract, it must receive a message from the brain, which come from nerves. Regular resistance training improves the ability of nerves to carry messages to a muscle. The messages will then arrive faster and cause more muscle fibers to contract. The result is improved strength.

Why are my muscles sore?

Have you ever felt a sore muscle? Yes, you have! It is common in the beginning stages of any new exercise program, especially resistance training.

Theories include, microtears, which are microscopic rips in the muscle fiber and/or surrounding tissues or during an intense exercise, a muscle may not receieve all the oxygen it needs. The last thing could be, that waste products build up around the muscle, resulting in muscle pain.

Soreness is not a serious problem, it is usually normal. There is a difference though between pain and soreness. Here are steps to take to relieve the soreness...

-Proper warm-up/cool-down

-Reduce weight or complete a lighter workout

-Drink water! Before, during, and after! Eat a proper diet.

-Give them a break! They need to repair before reworking out.