Overview of Eccentric Muscle Contraction

Braking Builds Bigger Muscles

Female hiker jumping downhill
Hagephoto/Getty Images

When you think of muscle contractions, most people think of causing a muscle to contract and shorten, such as during a biceps curl. However, another type of muscle contraction can occur in which the muscle lengthens as it contracts. This is called an eccentric muscle contraction. This is a type of muscle activation that increases tension on a muscle as it lengthens. Eccentric contractions typically occur when a muscle opposes a stronger force, which causes the muscle to lengthen as it contracts. It is sometimes called a braking contraction, negative work, or negatives.

Exercises That Cause Eccentric Contractions

Common exercises that cause an eccentric contraction include going down stairs, running downhill, lowering weights, and the downward motion of squats, push ups or pull ups. Eccentric contractions are common to many sports in which you need controlled or resisted types of movements.

Eccentric contractions are associated with the onset of delayed muscle soreness. Eccentric muscle contractions also appear to be associated with greater muscle strengthening than when using concentric contractions.

How Does a Muscle Contract While Lengthening?

Exactly how the muscle fibers work during eccentric contraction is still not well understood. Researchers think they understand concentric contraction, but the mechanism of eccentric contraction is still a mystery. Eccentric means "away from the center," and in eccentric contraction, the muscle is lengthened.

During an eccentric contraction, the muscle is activated and it is trying to shorten, or contract. But there is an opposing force, such as a heavy weight in your hand, that is overwhelming it to make it lengthen instead. As a result, the muscles and tendons act to control and slow down the action, but not to get it moving in the opposite the force. You are able to lower the weight with control rather than it simply pulling your hand towards the ground.

We use eccentric contraction constantly in daily activities. Walking is a combination of concentric and eccentric contractions. Your foot would simply flop down and slap the ground without the eccentric contraction of the shin muscles making it a controlled motion. When you are walking downhill, the quadriceps at the front of the thigh contract eccentrically to bend your knee. Moving your arm to put down objects is another example.

Your Muscles as Springs and Shock Absorbers

Eccentric muscle contraction produces negative work. This is because work is force times displacement, and the force the muscles are producing is in the opposite direction of the motion that happens. The muscle stores some of this mechanical energy and some of it is turned into heat. If there is a stretch-shorten contraction sequence, the muscle and tendon store elastic strain energy, which can then be used in the shortening concentric contraction. There is an optimum frequency to make use of this, a natural running or hopping pace where you get the most benefit from this stored energy. If you go slower, you use more energy on the concentric contraction without the assist of the stored energy.

Building Muscle With Eccentric Contraction

Eccentric exercise can rapidly condition and build muscles. For example, hiking downhill for the first time can result in lots of muscle pain in the quadriceps, especially the next day. But it only takes a few repeats for the muscles and tendons to become stronger and stiffer so the same hike or even longer downhills no longer cause delayed muscle soreness.

Athletic training commonly uses plyometrics and eccentric exercises to build muscle and power. Running, sprinting, jumping, hopping and throwing a ball all use eccentric muscular force enhancement to deliver power.

Pilates exercises also often employ eccentric contractions, resisting the springs in the reformer and gravity in body weight mat exercises. Eccentric exercises are commonly used in rehabilitation, such as for ACL damage.

Was this page helpful?
Article Sources
  • Eccentric Muscle Contraction. KenHub.