Posted in Fit basics

Types of Muscle Contraction

By now you probably know that muscles are able to do only one thing – to pull bones. Muscles never push, and that is the reason that they always come in “antagonistic” pairs. For example, your biceps flexes the elbow, while your triceps extends it; you need both.

So there is only one type of muscle contraction, right? Well, not quite. It is truth that muscles always produce pulling force, but if we take into account velocity of the weight being pulled, then there are three possible cases:

  1. Muscle pulls the weight and the weight travels in the same direction. For example, this happens when a dumbbell is traveling up in biceps curl. That is what we call “concentric” contraction, or “positive phase” of a rep.

  2. Muscle pulls, but the weight doesn’t move. As if you are simply holding a dumbbell in front of yourself, with the elbow bent at 90 degree angle. This is called “static” or “isometric” contraction.

  3. Muscle contracts, but the weight travels in the opposite direction. As when lowering the weight. That is what we call “eccentric” contraction, or “negative phase” of a rep.

Now ask yourself, in which of the three cases would you be able to keep at least some minimal amount of control over a really heavy weight?

Let’s say Arnie suddenly passed you an insanely heavy dumbbell and said, Holdt itt! Even if it was so heavy that you would had no chance of lifting it without help, you would probably be able to lower it to the ground with some control and dignity, right? And if the dumbbell you received was only reasonably heavy, you would perhaps be able to really hold it still for a few moments and make the mechanism in Arnie’s jaw grind into a smile. The conclusion is that muscles are strongest in eccentric, less strong in isometric, and weakest in concentric mode of contraction.

A smart athlete is in position to exploit this knowledge in order to make their workouts maximally effective. First thing to remember is that for any particular exercise, you should use such heavy weight that you are just barely able to very slowly lift in concentric contraction on your own. This ensures that all available muscle cells will be engaged in all three phases of the exercise.

Second thing is, in comparison to the positive phase, your muscle fibers are even more heavily engaged in the isometric phase of a rep. Thus it is very smart and effective to pause the lift in the top position so that you actively hold the weight in isometric contraction for a second or two. Do not simply switch from lifting the weight to lowering it in a blink of an eye. Stop and squeeze the muscles hard at the top. Feel the burn.

Finally, muscles are strongest in the negative phase of a rep, i.e. while lowering the weight. Consequently, this is the most stimulating phase for your muscles. Never let the weight pull you down as a rag doll. Actively control the weight on the way down instead. Imagine Arnie is watching you and you would have to freeze at any moment if he suddenly draws out a mini gun and yells, Staap! … That’s the control we’re talking about.

Remember, in all three phases of each rep in every exercise you must clearly show the weight who is the boss. Or your success as an athlete will be terminated.