Concentric Muscle Contractions to Build Strength

Man doing bicep curls
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When you consider what it means 'to use your muscles,' you might imagine the bulging muscles of a weightlifter straining to lift a heavy barbell, or someone flexing their biceps muscle in a show of strength. In both of these examples, what you are imagining is the action of a concentric muscle contraction. This is generally the type of muscle contraction that many people focus on when lifting weights at a gym in order to build strength. And this type of contraction is one in which the muscles do, in fact, typically bulge.

A concentric muscle contraction is a type of muscle activation that increases the tension on a muscle as it shortens.  A simple way to visualize this contraction is to do a biceps curl with a dumbbell. As you do this exercise slowly, you will see the biceps muscle will be activated, and shorten as you raise the dumbbell is lifted from the full-extended (downward) position by the thigh, to a fully contracted position to finish near the shoulder. Concentric contractions are a central aspect of the growth and development of muscle—as muscle contracts, it shortens, and this activation begins the process of muscle strengthening and hypertrophy.

Exercises That Cause Concentric Muscle Contractions

Although weight lifting is the most common exercise we think of that works muscles concentrically, there are many ways to activate your muscles as they shorten.

Typical examples of exercise that causes concentric contractions include the lifting phase of a bicep curl, the upward motion of a full squat or the upward motion of a pull-up. But you also use a concentric contraction in endurance sports and everyday movements. Concentric contractions are common to sports in which you need to generate a lot of power or explosive force. Sprints, running uphill, cycling, climbing stairs, and just getting up out of a chair all cause the quadriceps to contract concentrically. Carrying groceries, or a baby causes the biceps and forearms to contract and shorten. Doing curls or sit-ups cause the muscles of the abdomen to contract concentrically.

Other Types of Muscle Contraction

A concentric muscle contraction is one of the three types of muscle contractions, which are also known as muscle fiber activations. The method by which muscles increase in strength and size is a complex physiologic process that requires both muscle activation and rest. These occur when a muscle fiber or group of fibers is signaled by the brain via nerves to activate and increase the tension within the muscle. The actual contraction of the muscle occurs within very small structures called myofibrils, within the bundles of muscle's fibers. The method by which muscles increase in strength and size is a complex physiologic process that requires both muscle activation and rest.

There are three ways that a muscle fiber can be activated. A concentric muscle contraction is one of the three potential types of muscle contractions.The other two types of muscle contractions are eccentric muscle contractions and isometric muscle contractions. These other types of contractions are described briefly below:

  • Eccentric Muscle Contraction: During eccentric muscle contractions, the muscle fibers are stretched out. The muscle returns to the starting position of the exercise during eccentric contractions, such as a fully-extended arm.
  • Isometric Muscle Contraction: Isometric contractions do not cause any joint movement. An example is pushing against a wall. In such a situation, there is no lengthening or contraction of muscles. For this reason, isometric exercises are typically utilized in rehab programs, as the tension applied to the muscle remains consistent throughout the exercises, which can help a muscle to develop.

Overuse Injuries

While concentric muscle contractions are central to building strength, they can also cause some wear and tear on joints and overuse injuries. Isometric muscle contractions, on the other hand, place less stress on the joints because there is no actual movement in the joints. Concentric muscle contractions call for much joint movement, often repeatedly when weightlifting exercises are performed. These repeated contractions, and thus wear on the joints can build up and lead to joint issues and problems over time. Isometric exercises are recommended for individuals looking to rehabilitate, or simply looking to extend their joint longevity.

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