What Is Isometric Muscle Contraction?

How Isometric Exercises Can Benefit You Without Stressing Your Joints

A rock climber scales a wall.
A rock climber scales a wall. Henn Photography/Getty Images

An isometric muscle contraction, or static exercise, is one in which the muscle fires but there is no movement at a joint. In other words, the joint is static; there is no lengthening or contraction.

In this type of muscle contraction, there is no change in the length of the muscle, and there is also no movement at the joints, but the muscle fibers still fire. A solid example of an isometric exercise includes pushing hard against a wall.

While the muscles are still being utilized, and potentially stressed, and thus firing, but there is no movement at the joints. Joint movement would occur in an exercise such as a bicep curl. In such an exercise, the muscle fibers are utilized and there is also movement at the joints, as the arm bends and then returns to starting position.

Benefits of Isometric Exercises

There are a variety of benefits of isometric exercises. The benefit of isometric exercises include that they can be used for rehabilitation as well as general strengthening without placing stress on the joints. This is an important aspect of isometric exercises, because exercises that require joint movement can place a lot of stress on individual joints, especially over time with repeated usage. Isometric exercises are much easier on the joints in both the short term and the long term. They still cause the muscle fibers to fire, without the additional stress on the joints.

For this reason, isometric exercises are often used in rehab routines for individuals that have had joint problems or issues.

Some sports require a high level of static muscle strength. Gymnastics, yoga, rock climbing, and downhill skiing, for example, all have static strength requirements. These exercises require a lot of strength, if not a lot of joint movement.

It is important to note that if you feel any sort of joint pain while exercising, you should consult a doctor.

What is a Muscle Contraction?

An isometric muscle contraction is one of the three different types of muscle contractions, which are also commonly known as muscle fiber activations. These occur when a muscle fiber or group of fibers is signaled by the brain via nerves to activate and increase the tension within the muscle. This occurs when the muscles are stressed, such as during exercise like weight training. The muscles in a human body are made of bundles of muscle fibers that contain thousands of smaller structures called myofibrils, which is where the actual contraction occurs.

An isometric muscle contraction is one of the three potential types of muscle contractions. The other two types of muscle contractions are:

  1. Concentric Muscle Contraction: In typical weight training exercises, this is the actual lifting phase of any given exercise. Muscle fibers are shortened during concentric muscle contractions and strength is developed.
  1. Eccentric Muscle Contraction: In typical weight training exercises, eccentric contraction is the phase where the muscle returns to the original starting position of the exercise. During this type of contraction, the muscle fibers are stretched, rather than shortened.

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