You may have heard the term “eccentric contraction” and references to eccentric training, but you may not have a clear idea of what this concept means. Gaining a better understanding of eccentric contractions and their role in strength training can help you fine-tune your workout and get better results. It’ll also help you understand why you feel so sore after doing certain types of training.
What is an Eccentric Contraction?
There are two phases to a weight training exercise. These are called the concentric phase and the eccentric phase. When you do a biceps curl, you contract and shorten muscles in your upper body to slowly bring the weight up to your chest in a controlled manner – hopefully using good form. This is called the concentric phase of the exercise since you’re actively shortening the muscles. At the top of the movement, you pause briefly, which engages the muscles isometrically. Then you slowly lengthen the muscles to bring the weight back down in a controlled manner. This is called the eccentric phase of the exercise or eccentric contraction.
Many people think the bulk of the work is done during the concentric phase of an exercise when you’re contracting and shortening the muscle. In actuality, your muscles are exposed to greater tension during the eccentric phase as you resist the downward movement. During this phase your muscles have to develop tension to keep the weight from falling too quickly. This added tension stimulates muscle fibers and leads to further growth.
The Advantages and Disadvantages of Eccentric Training
Some bodybuilders do a form of training called negative or eccentric training where they emphasize the eccentric phase of an exercise. This is done to challenge their muscles differently, to stimulate new growth or break out of a plateau. To train negatively or eccentrically, you slow down the lengthening or eccentric portion of an exercise. Instead of lowering the weight in a few seconds, you actively resist the downward movement and reduce the speed of the eccentric phase so it lasts 5 to 10 seconds or more. This is more challenging than it sounds, but with increased challenged comes new growth. That’s the benefit of negative or eccentric training.
There’s also a downside to negative training. When you do this type of training, you need more recovery time since eccentric training places greater demands on muscles. In fact, emphasizing eccentric movements leads to greater microscopic tearing of muscle fibers, inflammation, and soreness. It doesn’t feel good, but it can stimulate greater gains in strength and mass. Because of the greater demands, it places on muscles, it’s not a good idea to do this type of training more than once a week. You also need to do a longer warm-up to prepare your muscles for the additional stress eccentric training places on them.
The Bottom Line?
Now you know what an eccentric contraction is and how it can help stimulate gains in strength and muscle size. It’s a good plateau-buster, but don’t overdo it, and don’t be surprised if you’re sore the next day.
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New Physiol. Sci , Volume 16, p. 256.
Med. Sci. Exerc. 2011 Jan; 43(1): 64-73.
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