A concentric contraction is a type of muscle activation that causes tension on your muscle as it shortens. As your muscle shortens, it generates enough force to move an object. This is the most popular type of muscle contraction.

In weight training, a bicep curl is an easy-to-recognize concentric movement. When you lift a dumbbell toward your shoulder, you may notice your bicep muscle swell and bulge as it shortens. This type of movement is one of the main ways to strengthen your muscle and encourage hypertrophy — an increase in your muscle size.

Though effective, this type of contraction alone will not produce strength or mass results compared to workouts that combine different muscle contractions. There are three main types of muscle contractions:

  • eccentric
  • concentric
  • isometric

Besides concentric contractions, muscle contractions can be split into two other category types: eccentric and isometric.

Eccentric

Eccentric contractions are lengthening movements of your muscles. During this muscle movement, your muscle fibers are stretched under tension from a force greater than the muscle generates. Unlike a concentric contraction, eccentric movements do not pull a joint in the direction of a muscle contraction. Instead, it decelerates a joint at the end of a movement.

Using the same bicep curl exercise, the force to bring a dumbbell back down to your quadricep from your shoulder is an eccentric movement. You may notice your muscle elongating as it’s activated. Combining eccentric and concentric muscle contractions produces greater results in strength training, as it increases muscle strength and mass. However, you may be more prone to exercise-induced injuries during eccentric movements.

Some movements or exercises that display eccentric movements include:

Isometric

Isometric movements are muscle contractions that do not cause your joints to move. Your muscles are activated, but they are not required to lengthen or shorten. As a result, isometric contractions generate force and tension without any movement through your joints.

The best way to visualize this contraction is through the act of pushing up against a wall. When you perform any of these actions, the tension applied to your targeted muscle is consistent and does not exceed the weight of the object you are applying force to.

Common movements that demonstrate isometric contractions include:

  • plank holds
  • carrying an object in front of you in a steady position
  • holding a dumbbell weight in place halfway through a bicep curl
  • bridge holds
  • wall sits

Concentric muscle contractions involve movements that shorten your muscles. In exercise, concentric movements target muscles to perform action. The heavier the object is you’re trying to lift or move, the more strength that is generated.

Concentric movements are effective in producing muscle mass. However, you will need to perform twice the amount of repetitions to produce the same results as a combined eccentric and concentric workout.

Common concentric movements and exercises include:

Concentric contractions are essential to building muscle. However, they can cause wear and tear on your joints, increasing your risk of injury and overuse. Concentric movements depend on joint movement for proper function, but repeated exercises and contractions can lead to strain and soreness.

Before and after performing any exercise, be sure to stretch to loosen your muscles and reduce strain. If you begin to experience muscle pain that persists longer than a few days or weeks, visit your doctor. This could be indication of a more serious injury.

Concentric contractions are muscle movements that shorten your muscle fibers when performing an action. Essential to increasing muscle mass, concentric movements help to increase strength. But, results are not as sufficient as workouts that combine all three types of muscle contractions.

Over time, repeated concentric contractions can lead to injury. If you begin to experience pain or weakness after performing a concentric exercise, consult with your doctor.