The 4 types of muscle contraction and the different types of force.

✓ The first is concentric contraction, which means the reduction of muscle insertions. It is the one most commonly used in bodybuilding and strength training.

In biceps curl, I do forearm flexions. This movement is characterized by a shortened muscle.

✓ The second type of contraction is the opposite: eccentric contraction. This is the lengthening of the muscle.

In the biceps curl example, the eccentric movement begins with both forearms close to the chest falling toward the hips. With this type of contraction, we gain more force than with a concentric contraction.

It is easier to slow down a load than to lift it. We will see the impacts on training later. When we do classic bodybuilding exercises, we do both movements, concentric and eccentric. We focus on the load in the concentric phase, since in the eccentric phase we could have worked 25 to 30% more.

If we are doing 80% of our 1RM (maximum repetitions) then in the eccentric phase we will be at approximately 50 – 60% of our maximum eccentric phase.

✓ Third type of contraction, isometric. How can we define it? The goal is to hold a load at a certain angle. In the biceps curl, we must hold a certain muscle contraction.

We also call this static work. The advantage of this type of contraction is that we gain strength at the precise angle on which we are working (plus or minus 10 degrees). The biggest disadvantage is that you lose speed.

For static exercises, such as abdominal or lower back strengthening exercises, this type of contraction is primarily used since that is primarily how they work on the field.

✓ The last type of contraction is plyometrics. This system is found in sports such as running, throwing and jumping movements. What happens with plyometrics?

There is a sudden stretch of the muscle, a rapid eccentric contraction, which is immediately followed (spring concept) by a concentric contraction.