Concentric contraction is one type of muscle contraction that happens as a result of isotonic exercise. Isotonic exercise is simply a range of movement combined with a fixed weight or resistance load. One very simple example of isotonic exercise is an individual lifting an item off of a table.

As a kind of "one half" of isotonic exercise, concentric contraction is a specific muscle response that can be combined with its opposite, eccentric contraction, in order to perform many common activities.

Concentric contraction happens when a muscle is actively working on an object. People refer to instances where a muscle group is able to manipulate a smaller weight load as a concentric contraction.

In contrast, an example of an eccentric contraction is when a muscle group is not actively handling a weight load, but just passively responding to it by distributing the weight to muscles and joints. This happens when weight is too much for a muscle group to actively move in the desired direction, but it also happens when the individual makes the decision to move the item along with gravitational force, rather than against it.

Some simple examples include walking up and down stairs, where walking upstairs results in concentric contractions, and walking downstairs results in eccentric contractions. There are also free weight activities like the bicep curl; concentric contraction happens when the user pushes the dumbbell up against gravity, and eccentric contractions happen when the dumbbell is lowered.

One reason that many trainers and fitness experts consider concentric contraction important is that it works with common principles of progressive resistance for free weight or fixed weight training. When users of free weights or fixed weight machines keep working on sets of lifts with heavier and heavier weights, they are increasing muscle capacity and muscle mass, usually at a pretty good rate. Concentric contraction is the essential muscle response that facilitates this development.

Another philosophy that makes concentric contraction important is the idea that a combined menu of concentric and eccentric muscle training can bring about a quality result. Some experts point out that diversified concentric and eccentric muscle training helps the body to respond to a wide variety of resistance challenges, where just one or the other may produce more limited results. Concentric contraction is also part of the duality for exercises known as plyometrics, where an explosive movement results in more muscle building.

Concentric contractions in muscle work are generally easy to add to a fitness schedule. The fixed and free weight options in most gyms make it easy to step into a weight lifting environment in between other activities like running on treadmills or ellipticals, swimming and more. Many of these gyms provide trainers who can advise on the right mix of activities for a particular body type and body condition. Learn more about the various types of common exercise that produce good muscle results, and put them to work to strengthen and tone for a healthier future.