Definition of Eccentric Weight Training

A bicep curl with a dumbbell.
A bicep curl with a dumbbell. berekin/Getty Images

Eccentric muscle action is a lengthening of the muscle while contracting. It is a braking force or is in opposition to an action that shortens the muscle. If you have your arm bent in a biceps curl and straighten your arm from the curl position, the movement is eccentric. When you curl your arm, the movement is concentric, which means a shortening under contraction of the target muscle, in this case the biceps.

Also Known As: Negative training, negative work. The muscle is absorbing mechanical energy by lengthening while under load. This energy is released by elastic recoil and heat, raising body temperature.

Eccentric muscle contraction was originally called excentric (by Erling Asmussen in 1953), meaning away from the center of the muscle. This evolved into eccentric.

Examples of Eccentric Contractions in Exercise

  • Lowering a weight during a curl
  • Downward motion of squatting
  • Downward motion of a push-up
  • Lowering body during a crunch or roll up
  • Lowering body during a pull-up

Why Perform Eccentric Weight Training?

Some weight training advocates say that specific eccentric training can help build muscle size and strength superior to results from standard concentric-eccentric movements. A justification for this is that eccentric muscle contraction is stronger than concentric contraction, which allows you to enlist heavier weights. To accomplish this, you may need to employ a helper or spotter to assist with the concentric part of the lift, and then you do the eccentric part alone.

While an eccentric contraction uses less energy and requires less oxygen consumption than a concentric contraction, eccentric emphasis exercise may boost resting energy expenditure. Researchers found a 9% increase in resting metabolism for three days after a full-body eccentric emphasis workout. This could be due to muscle repair processes brought about by such workouts.

Eccentric exercise is often used in rehabilitation and physical therapy. Rehabilitation after anterior cruciate ligament (ACL) damage uses eccentric exercise. Eccentric exercise may also be recommended for the elderly to build muscle strength while not taxing the heart and lungs. Eccentric strengthening may be used in hope of reducing the risk of Achilles tendonitis and calf strain.

Eccentric Emphasis Training

In this variation of resistance training, the concentric part of the exercise is done with a one-second load, such as lifting a weight in a biceps curl for one second. Then the unloading is done over three to five seconds to give maximum emphasis to the eccentric move. For example, slowly lowering the biceps curl over three to five seconds.

Delayed Onset Muscle Soreness with Eccentric Exercise

Muscle soreness after a workout may be increased with a greater volume of eccentric work. Research continues into what causes this. Eccentric exercise may stretch and strain the sarcomeres, causing both contractile and noncontractile tissue damage and the unrestrained release of calcium ions within the sarcomere. Researchers and exercisers note the repeated-bout effect: performing eccentric exercise may produce delayed onset muscle soreness, but then repeating the exercise a week later results in less soreness.

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