You guys are doing so many exercises. Most of the time you focus on strengthening and build your skeletal muscles. When we take your main upper arm muscle which is called biceps brachii muscle, fitness trainers instruct you to isolate the muscle and do its action with some resistance to strengthen it. So, they utilize exact action to these workouts to build your biceps. In this article, let’s discuss about the types of muscle contractions. By knowing the science behind the muscle contractions, you are able to reach your fitness goals with less time than you expect.

What is a skeletal muscle?

First and foremost, we have to get some time to get the basic knowledge about muscles. There are mainly three types of muscles in the human body. They Skeletal muscles, Smooth muscles, and cardiac muscles. Among these three types, Cardiac muscles are only situated in your heart. Then smooth muscles are located most of the time at the covering of internal organs. However, we can not control the actions of both these muscle types. But skeletal muscles are so different from these two types.

Skeletal muscles are made of skeletal muscle cells. Skeletal muscle cells are long and cylindrical, they are commonly known as muscle fibers. A muscle fiber is composed of many fibrils, which give the cell its striated appearance. These muscle fibers contain multiple nuclei and you can consciously control the muscle actions.

Every skeletal muscle fiber is innervated by a motor neuron at the neuromuscular junction. This is another specialization of the skeletal muscles.

Types of muscle contractions

You clearly know that if you want to move an object, you have to shorten your muscle in which responsible for the exact action. The force which is generated by the shortening of muscle is called muscle tension. Sometimes, this muscle tension is increased without moving the object. So mainly we can identify two types of muscle contractions. They are isotonic contractions and isometric contractions.

Isotonic contractions                                                                                                                      

In Isotonic contractions, where the tension in the muscle stays constant, a load is moved since the length of the muscle changes. According to the changing of muscle length, there are two types of isotonic contractions.

  • Concentric contractions

In concentric contractions, the length of the muscle is reduced. Muscle is shortening. We can take the dumbbell biceps curl as an example. Here, biceps brachii muscle is contracting, and weight is brought upward with increased muscle tension. As the biceps contracts, the angle of the elbow joint decreases as the forearm is brought toward the body. It is key to mention that during the movement muscle tension is constant.

  • Eccentric contractions

Like concentric contractions, you also can activate the muscle by lengthening it. So, in the dumbbell biceps curl, you should lower the dumbbell by elbow extension in a really slow and controlled manner because the gravity also projects the same direction. It is significant to follow the real technique to get the benefit of eccentric contractions. Eccentric contractions also used for maintaining movement and balance of the body. During eccentric movements, muscle tension is maintained in a constant value like concentric contractions.

Sometimes concentric contraction is named as positive work and eccentric motion is considered as negative work.

Isometric contractions

This is an uncommon type of muscle contraction. Because you can’t see any movement, but the muscle contracts. Isometric contractions are also called static contractions. Isometric contractions involve sarcomere shortening and increasing muscle tension, but do not move a load. Especially in an isometric contraction, we apply the resistance that can not overcome. So, you try to move it. Your muscles are working to do that. However, the object is stable.

What is Isokinetic?

Isokinetic means constant speed. Isokinetic contraction is a fairly new concept. After creating an electromechanical device, it could control the rate of movement. So, In Isokinetic exercise, the rate of movement does not change. The static cycle is a good example of this type of contraction.

When we come to a conclusion of types of muscle contractions, Actually, the name contraction suggests you a shortening of the muscle, but it is not a correct term for study the types of muscle contractions. Now, you clearly know that both eccentric and isometric muscle contractions are not shortening of muscles.

Credits for featured image: Photo by Andrea Piacquadio from Pexels

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