Why do our shoulders get stiff?

5 min readMar 21, 2023


stiff shoulders

Continuing our journey, today we explored another article originally posted on our Japanese blog, on note.com — Sunbears Official【公式】 — written by Yuriko Hiroura and translated & adapted by Yuge Zhao! This time, we discuss a very important topic, given the transition to more busy lifestyles in today’s world.

So, have you ever wondered why our shoulders get still?

After working on a computer for a long time, many people have experienced such pain at the base of the neck or in the shoulders when they look up, a problem that has become increasingly common worldwide. For example, a study from the UK showed that the prevalence of shoulder complaints in the UK is estimated to be 14%, with 1–2% of adults consulting their general practitioner annually regarding new-onset shoulder pain. Do you know why our shoulders get stiff?

Causes of Stiff Shoulders

The most common cause of shoulder stiffness is muscle strain, but it can also be caused by other factors such as eye strain, lack of exercise, cold, stress and internal organ tension. Muscle fatigue, in particular, is said to be caused by the fact that when humans first evolved to walk on two legs, the body formed a support structure to keep it upright, in which the neck and shoulders were very prone to being under tension to support the head. In addition, in recent years, with the high involvement of smartphones and computers in people’s lives, it has become increasingly easy for us to stay in the same position for a long time to use these devices.

You are reading this article on your smartphone or computer. Imagine your current posture. Are you hunched over, with your neck stretched forward?


Tension-Prone Muscles

The trapezius is a well-known muscle of the shoulder. Firstly, its structure dictates that it is easily tensed. When humans evolved from quadrupedal to bipedal walking, the legs became more burdened, and the arms were freer. Furthermore, it is not the bones but the muscles that primarily keep the arm attached to the trunk, allowing the shoulder to move more freely than the hip joint. The trapezius muscle was primarily given this connecting role. It connects the scapula (arm) to the clavicle (torso), but at the same time, this muscle is under constant tension from the shoulder to the neck, as it constantly pulls on the heavy arm to prevent it from falling off.

Straight Neck

In addition to muscles naturally prone to tension, postural problems are a significant factor in shoulder stiffness. These days, we spend more and more time looking at screens, whether at work or in private. When you check your laptop or smartphone, you will inevitably be in a posture where you are staring at the screen. And when hunched over, the face is more likely to move forward naturally to maintain balance. If this forward-leaning posture continues, the cervical arch will gradually collapse, causing the neck to straighten.

A straight neck is a condition in which the neck’s bones are straight or inversely curved.

People’s heads are heavy, but if you continue to live with your head stretched out, your neck will atrophy, blood circulation will be affected, and pain around your neck and shoulders will worsen. Don’t underestimate it as just stiffness in your shoulders or neck, but take care to correct your posture when you take your eyes off your phone or computer. Try stretching with your chest open, accompanied by relaxed breathing, and take a few minutes to stretch the neck.

stretching exercise

Sedentary Inactivity

Some may say, “I know my posture is bad, but I’m mindful of changing my posture”. However, the root of the problem is the hidden danger of sitting too much. How long do you think office people stay seated each day? On average, people in the United States spend up to 7.7 hours a day sedentary, while in Japan, people are even more sedentary than 9 hours (9.4 hours for men and 8.8 hours for women). This excessive sitting may increase the risk of diseases such as diabetes, impaired blood circulation, heart disease and mental health problems.

The point is that prolonged sitting weakens the anti-gravity muscles (such as the erector spinal and rectus abdominis) that maintain this posture, making it difficult for them to work. Blood flow is also reduced, making the neck more prone to stiffness, back pain and hardening of the hips and thighs. In other words, being sedentary can lead to a ‘negative spiral’ that makes poor posture increasingly difficult to heal.

Specifically, bad postures can be improved by relaxing the tense muscles and strengthening the weak ones. However, until then, simply standing up every 50 minutes can bring about a significant improvement in accumulated damage. If you spend a lot of time sitting continuously, give it a try gradually.

You can find many simple stretches and exercises on Youtube, such as exercises to help your upper back become more flexible and sternocleidomastoid relaxation techniques to prevent your face from moving forward, so give them a try! Getting into the habit of stretching and exercising is also recommended, even if it is for 5 minutes a day.

Reference List

Guyver, P.M., Bruce, D.J. and Rees, J.L. (2014) Frozen shoulder–A stiff problem that requires a flexible approach. Maturitas, 78(1), pp.11–16.

Hyogo Medical University (2019) Health Center News [online] available from https://www.hyo-med.ac.jp/department/health-center/news/center_news/center2019autumn.pdf

Park, J. H., Moon, J. H., Kim, H. J., Kong, M. H., & Oh, Y. H. (2020) Sedentary Lifestyle: Overview of Updated Evidence of Potential Health Risks. Korean journal of family medicine, 41(6), 365–373. https://doi.org/10.4082/kjfm.20.0165




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