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Understanding the Relationship between Exercise and Muscle Contraction

Feb 13, 2010

Different types of muscle contractions occur during the various exercise methods that you take part in. It is important to understand what exercises strengthen muscles in different behaviors, making physical fitness goals easier to achieve.

Muscle Contraction

Any movement in any muscle group gets listed as a contraction, even though the exact definition of the term generally means to shorten or decrease in overall length. However, exercise based muscle contractions happen with every exerted force, regardless of the specific exercise or workout regimen. Even when we walk, we generate a force that extends muscles in a lengthening contraction, which also includes the shortening contraction when the knees lock and the legs fully extend (making the muscle fiber shorter than when in stride). Different types of muscle contractions happen due to the action you put on a body part.

Lengthening Muscle Contractions – Eccentric

Often times, you experience much more eccentric muscle contractions than the other types that occur during exercise. In most exercises involving cardiovascular activity, such as running, stepping, walking and nearly anything that involves extending, your legs result in eccentric muscle contraction. Another example that you deal with occurs during the lifting and setting of objects; setting a heavy object on to the ground in a controlled manner often requires both arms to become fully extended.

Stretching and muscle strengthening occur as a direct result of lengthening muscle contractions, which often bring about muscle soreness. Unlike concentric or muscle shortening exercises, eccentric exercise puts continual strain on muscle fibers, providing you with a burning sensation (that commonly occurs at the end of a long set of repetitions).

Shortening Muscle Contractions – Concentric

This type of muscle contraction occurs when muscle fibers get shortened. Concentric contractions happen as a result of your muscle decreasing the maximum weight load that it can normally handle. An example of a concentric exercise, the bicep curl, provides a great demonstration for you to better understand the concept of the contraction; the weight becomes hard to lift during the first phase of the lift, but then suddenly becomes much easier during the last few inches of pull when the weight nearly touches your face.

Steady Muscle Strain – Isometric

Isometric exercises and movement force muscles to hold a fixed position so that the muscle tissue and fiber does not stretch, bend, shorten or lengthen. If you hold an object of any size so that the weight gets suspended in the air, equal force gets applied in both directions so that the muscle does not experience either eccentric or concentric contraction. Anytime an equal amount of force gets applied by the muscle and the object being acted upon, an isometric contraction will occur.

Stretching and Muscle Contraction

Before, during or after exercise, you should always stretch. Although stretching commonly goes without the label of an exercise type, the act of stretching does cause muscle contraction. Muscles become passively lengthened in stretches such as sitting toe touches; the hamstrings lengthen even though the muscle group does not perform actions, such as in a jump or squat.

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