An eccentric contraction is a type of muscle movement where the muscle lengthens as it is put under tension. While the word “contraction” often conjures up an image of a muscle shortening, it is important to note that eccentric contractions involve an extension of the muscle. These types of muscle movements are very common. For athletes, the risk of injury is often higher when muscles are being lengthened in an eccentric contraction. Injuries classified as pulls and strains often involve a muscle that was stretched too far.
The purpose of an eccentric contraction is to regulate a movement. The lengthening muscle resists the tension to keep the movement smooth and even. It also protects the joints by controlling the speed, angle, and direction of the movement. Multiple muscles usually work at the same time and can pull in different directions for highly controlled movements.
In a simple example of an eccentric contraction, a person can start with the elbow bent and the hand on the shoulder. When the arm is unfolded to straighten it out, eccentric contractions are occurring to control the movement and prevent the elbow joint from experiencing damage. If these muscles in the arm didn't create some resistance, the arm could snap out and damage the elbow joint. Eccentric contractions can also be seen in activities like walking, where the muscles work to protect the ankle and knee from injury as people complete steps.
People can injure themselves during an eccentric contraction by putting too much strain on a muscle. Weight lifting is a classic example. People who lift weights that are too heavy may strain their muscles as they stretch under resistance. Likewise, deep stretches before someone is fully warmed up can injure muscles that are stretched too far. People can reduce their risk of muscle injuries by warming up thoroughly before exercise and developing tapered workout plans that promote the development of strong, toned muscles over time.
Certain types of athletic training require the use of eccentric contractions. Working muscles in this way tends to help people develop long, even, highly toned muscles. This type of training is accomplished by creating resistance that will stretch the muscles, either with the use of exercise equipment or certain stretches and poses. Pilates is an example of a form of exercise that utilizes eccentric contractions to work the muscles in the body and help them develop strength and tone.