There are two types of muscle contractions: concentric and eccentric contraction. Concentric contraction makes more sense to most of us because it involves shortening or tightening the muscle, the action we generally associate with muscle contraction. Eccentric muscle contraction, however, while still a contraction of the muscles, is in fact lengthening them.
Our muscles contract eccentrically when we are trying to slow movement down. Hence, eccentric contraction is also known as a breaking contraction.
If you’re finding it hard to get your head around this phenomena, you’re not alone. Despite the immense advancements in modern medicine, no one has actually made the breakthrough discovery as to how eccentric muscle contraction actually works.
But we do know what it is, why it occurs, and we certainly know that after an intense workout, eccentric contraction feels quite different to normal contractions – it hurts!
When do we use eccentric muscle contraction?
Whenever we have to slow something down or control our movement, we are generally using this “breaking” eccentric contraction. The clearest example of concentric vs eccentric contraction is when you lower a hand-held barbell. When you pick up a heavy barbell with your hand and flex your elbow you are contracting your bicep muscles to raise the barbell (concentric contraction). In contrast, when you slowly lower the barbell down towards the ground, you are using eccentric contraction.
Think about this: your muscles are still contracting as you do this movement, but not enough to stop the barbell moving towards the floor. You are slowly breaking the movement.
Want more examples of eccentric contractions?
When your quadricep muscles contract eccentrically as you walk down the stairs, particularly if you are trying to step very quietly or gently. Your quadriceps are trying to control the action of your knee so that your knee doesn’t straighten too far or too quickly.
When playing tennis, the extensor muscles on the back of your forearm will do eccentric contractions to avoid your wrist flexors going into a strong, floppy flexion. Your extensor muscles help stabilise and control the movement of your wrist.
When walking, your tibialis anterior controls the action of your feet by eccentric contraction. Without this happening, your fleet would slap around like dead fish on the end of a pole.
Another profound difference: pain
Ever noticed extreme pain in your shins the next day after running down a few flights of stairs? This is because your tibialis anterior has been working hard in eccentric contraction. It is also why your wrists and forearms hurt after playing your first round of tennis in the season.
The extreme muscle pain experience the next day is known as delayed onset muscle soreness (DOMS). DOMS has been described as “muscle fever”, that distinctive and intense muscle pain that feels a little bit like you have a fever coming on.
DOMS at its strongest levels can interfere with range of movement and even daily activities. By this, we don’t mean daily activities like going for a jog or doing a pump class. We mean basic activities like getting out of bed, tying shoelaces or sitting on the toilet. Or for athletes working hard on their upper bodies, brushing teeth or combing hair will suddenly become an entirely new experience, and a painful one.
Remember, a defining feature about DOMS is that it never occurs on the day of your workout. It occurs one or even two days after exercise and you can blame it largely on eccentric contractions.
DOMS can happen after both concentric and eccentric contraction, but eccentric contraction seems to result in far worse pain. Why? No one knows for sure. What we do know is that your intense muscle pain is due to eccentric muscle contraction, and that generally, all you can do is exercise some patience and wait it out.
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