Muscle imbalances occur when there are large differences between these characteristics which should otherwise be similar, this can be due to an adaptation or dysfunction and is categorized as either functional or pathological.
Why do imbalances occur?
The causes of imbalances will vary from person to person. A pathological imbalance may be due to an injury, which renders the muscle temporarily disabled, the duration of time in which it is unused results in decreases in muscle size and strength. On the other hand, functional imbalances may be a result of playing a particular sport, this is common amongst tennis or golf players, who often have a more dominant, preferred arm.
Imbalances are found in either the body or the joint. A body imbalance can be seen in the description of the tennis/golf player I mentioned above, where there is an asymmetry between each limb.
A joint imbalance refers to the muscles that surround a joint on one side. If muscles on one side of the joint become weaker or stronger than the other, they may cause movement dysfunction. An example of this can be seen where the muscles at the front of the shoulder joint (anterior deltoid and pecs) outgrow/strengthen the ones on the rear ( rhomboids, traps, and rotator cuff). This can cause the shoulder to be more internally rotated (rolled forward) and the individual may struggle to lift their arm up overhead, unable to achieve full range of motion (ROM).
Causes of muscular imbalances:
- Natural development
- Being left or right-handed
- Crossing your legs a particular way
- Carrying a bag on the one side
- Sleeping on one side more than the other
- Having poor posture
- Playing sport
- An unbalanced exercise program
- Exercising with improper form
Are imbalances always an issue?
Although ‘imbalance’ may sound like it has negative connotations, it is not necessarily a bad thing. For example, in sports such as baseball, tennis, and soccer, players will develop more muscle size and strength in their dominant limb, this will allow them to generate more power, coordination, and strength when hitting the ball. It is important to understand, that having an imbalance does not necessarily mean you will have issues associated with it. Many people live their whole lives with one limb shorter, stronger, weaker, or tighter than the other, and never have any problems. A perfect example is Usain Bolt. Bolt was born with severe scoliosis where his spinal curvature was greater than 40 degrees. The severity of his scoliosis resulted in one of his legs being 1.27cm longer than the other. As you can imagine, being a sprinter, the length of your legs matters, being able to run on them correctly is essential! Due to the discrepancy in limb length, he spent the majority of his sprints on his left (longer) leg as opposed to his right, yet he ended up running 9.58s for the World Record. Bolt is an example of what the human body can do, highlighting its amazing ability to adapt, despite the muscular imbalances that he had.
What problems can imbalances cause?
Determining whether or not you have an imbalance can be difficult, most of the time it is identified by a physiotherapist or doctor after an injury, or symptoms have occurred that bring it to the fore. Although some people may go their whole lives never having an issue, others can have ongoing problems that hinder their ability to complete activities of daily living and require extensive rehabilitation. Research conveys that high levels of asymmetry between sides of the body have been associated with an increased risk of injuries, chronic lower back pain (LBP), and postural problems. Furthermore, if the imbalance is pathological and beginning to inhibit function, this can cause joint dysfunction and negative changes in movement patterns.
How do you fix a muscular imbalance?
The first step to rectifying an imbalance is ensuring that it is diagnosed correctly in the first place. You may be able to do this yourself if it is obvious, or if you are unsure but notice something is up, get someone who is qualified to help you out.
Some ways to begin correcting muscular imbalances:
- Ensure it is correctly identified
- Fix the underlying problem
- Do more work on the opposite side
- Let the weaker side dictate your workout volume
- Start with the weaker side
- Use unilateral exercises
Whatever the imbalance is, doing the above consistently is essential, as correcting it can take time, especially if it is something you have had for a while.
It is pretty common to have some form of imbalance, and it will depend on the effect it has on you as to whether or not it is an issue. Lifestyle habits such as being right or left-handed, playing a sport that favors one limb, sleeping on one side more than the other, or crossing your legs a particular way can cause discrepancies. However, this doesn’t mean you need to stop playing out of fear of injury, change sleeping sides, or start writing with the opposite hand, as you may never have an issue that requires attention. If you have an imbalance that hinders your ability to complete activities of daily living, and shows large differences in your strength or range of motion, I would do something about it sooner, rather than later. Not only is rectifying an imbalance important at that point, but it could be a sign of an underlying issue that is yet to be diagnosed or needs to be managed before it causes other issues up the chain.
Green, B., Bourne, M., van Dyk, N. and Pizzari, T., 2020. Recalibrating the risk of hamstring strain injury (HSI): A 2020 systematic review and meta-analysis of risk factors for index and recurrent hamstring strain injury in sport. British Journal of Sports Medicine, 54(18), pp.1081-1088.
Malliou, P., 2004. Effective ways of restoring muscular imbalances of the rotator cuff muscle group: a comparative study of various training methods. British Journal of Sports Medicine, 38(6), pp.766-772.
Renkawitz, T., Boluki, D. and Grifka, J., 2006. The association of low back pain, neuromuscular imbalance, and trunk extension strength in athletes. The Spine Journal, 6(6), pp.673-683.
Śliwowski, R., Jadczak, Ł., Hejna, R. and Wieczorek, A., 2015. The Effects of Individualized Resistance Strength Programs on Knee Muscular Imbalances in Junior Elite Soccer Players. PLOS ONE, 10(12), p.e0144021.
Victora Ruas, C. and Vieira, A., 2017. Do Muscle Strength Imbalances and Low Flexibility Levels Lead to Low Back Pain? A Brief Review. Journal of Functional Morphology and Kinesiology, 2(3), p.29.
Yeung, S., Suen, A. and Yeung, E., 2009. A prospective cohort study of hamstring injuries in competitive sprinters: preseason muscle imbalance as a possible risk factor. British Journal of Sports Medicine, 43(8), pp.589-594.
Please note that the health-related information contained on this website is provided for general information purposes and is not intended to be a substitute for professional medical advice or for the care that patients receive from their healthcare professionals. This information is not medical advice, and for advice on your specific needs, you should always consult your medical practitioner.