A quick post about the way muscles move during an exercise. I’ve seen many guys in the gym talking about about things related to this topic and they seemed a bit confused. Therefore i have written it out briefly and in a simple way so everyone knows what happens when you lift weights etc. Its fairly straight forward!
For the sake of demonstrating this i’m going to choose a Bicep Curl, i’m not particularly a fan of the exercise, as i mainly perform Compound movements, however it is excellent for grasping the concept.
Concentric Contraction: Muscle shortened. Muscle Shortens against a resistance. The two heads pull together.
Eccentric Contraction: Muscle Lengthened. Muscle Lengthens against resistance.
So you have your dumbell in hand, and you start to curl it upwards, this is the Concentric part of the exercise. Then as you go back down this would be the Eccentric part!
A useful thing to know would be that in the Eccentric Contraction, microscopic tears happen, these tears then heal later during the Repair & Growth Phase! Making them bigger. This is muscle growth! So it makes sense if you train for Hypertrophy (Muscle Growth) you should be performing your repetitions at a controlled pace and not trying to get as many reps out as possible like you see people doing. Perhaps they are training for something in specific of course so don’t judge them!
Concentric & Eccentric: Moving contractions. These are called Isotonic.
Static: (Held still, such as a Plank). Isometric.