If you are going through physical or occupational therapy to recover form an injury, then you are probably hearing some terms that you are not familiar with. This article will help clear up that confusion and give you a new perspective as to why you are performing those exercises. Understanding the purpose behind the exercise not only gives you something to think about while you’re working away at therapy but will help you long after therapy if you work out!
There are three types of scenarios where the muscle produces tension which involve muscle shortening (concentric), muscle lengthening (eccentric), and where the muscle stays the same length (isometric) (Matte, 2019). Let’s start with Isotonic movements. This type of movement is the one you will be most familiar with. Isotonic movements consist of eccentric and concentric movements. Concentric movements are associated with the shortening of the muscle belly (Kim et al., 2015). In other words, the bicep would perform a concentric movement causing the elbow to flex or bend as the muscle shortens. An eccentric movement would be the triceps muscle belly response as the elbow flexes. As the bicep contracts to flex the elbow, the triceps muscle lengthens. This would be an eccentric movement (Kim et al., 2015). Examples of concentric strengthening would include anything that involves joint movement with resistance. Running, walking, lifting, pushing and pulling!
The strengthening that we have been talking about so far involve movement of joints and shortening and lengthening of muscle bellies. Now we are going to talk about isometric strengthening that takes place without the need for joint movement, shortening, or lengthening of the muscles (Matte, 2019). If you have ever performed a plank hold before, you have performed isometric strengthening. Another form of this would simply involve maintaining proper posture while sitting at a desk! According to Matte (2019), isometric strengthening does have potential to raise blood pressure, so this is not recommended if you have hypertension. Examples of isometric strengthening techniques would involve yoga, plank holds, postural re-education, wall sits, and hollow body holds.
This is also used in rehabilitation settings for individuals with shoulder, wrist, or elbow pain. Applying gentle resistance to muscles without stressing them with repetitive concentric/eccentric movements could allow the patient to strengthen comfortably and build confidence in their body. As the confidence builds and the soreness dissipates, the patient can progress to more isotonic movements such as internal rotations, bicep curls, or wrist curls!
For more information on eccentric strengthening check out our previous blog post on eccentric strengthening!
If you are having pain in your hand, wrist, or elbow check out our diagnosis database to learn more about what your symptoms are telling you!
References
Kim, M. K., Choi, J. H., Gim, M. A., Kim, Y. H., & Yoo, K. T. (2015). Effects of different types of exercise on muscle activity and balance control. Journal of physical therapy science, 27(6), 1875–1881. https://doi.org/10.1589/jpts.27.1875
Matte, M. (2019, August 26). Isotonic vs. isometric muscle exercises. LIVESTRONG.COM. https://www.livestrong.com/article/449913-isotonic-vs-isometric-muscle-exercises/.
