Over the last few years, technology has advanced greatly. Computers and smartphones now play a significant role in our everyday life. In 2014, it was estimated that 42% of US population 18 years or older possess a tablet computer. We think of these portable devices as a convenient way to stay connected with our work wherever we go. However, the potential for its use-related injury has not been evaluated until recently. While desktop manufacturers provide a guideline to set up the desktop correctly, there seems to be no manual for what the correct posture for using a tablet computer is.
By investigating the head-neck postures during tablet computer usage, researchers were able to explain the correlation between owning a tablet computer and having neck/shoulder discomfort. The extensors of the neck are vulnerable to fatigue, often due to the gravitational moment of head mass during flexed postures. There were some studies that back up the relationship between flexed posture and neck pain. Most of the time, tablet computer users seem to put them in lap, which puts a lot of gravitational of head mass on their neck.
Given the choice, most of the time, tablets users choose to put the tablet in a low position to their head, either in the position shown in Table Low position or Self-selected position. Comparing those with the Neutral position, much more gravitational demand is required. Surprisingly, research shows that the common posture of tablet users result in 3-5 times mechanical demand on neck muscle compared to neutral posture. To understand this clearer, we can examine a simplified model showing the force of head mass exerting on neck muscles.
Gravitational demand on the neck is calculated as (Whead x rhead)/Mmus
Thus, it makes sense as you lower your head, rhead, which is the distance between the head’s center of mass and the neck spine, increases, leading to an increase in gravitational demand. Using all these data, a succinct figure was generated through the study.
What the figure shows is the extremely high gravitational demand when the tablet was used in any postures other than neutral, especially in lap low position. What the figure also shows is that there seems to be no significant difference between reading and typing in respect to the effect on gravitational demand. However, I believe the tasks people do on tablets affect their preferred posture. A quick survey about which posture is preferred when reading, typing, watching movies might contribute to the study.
So what’s the take from the study? Using tablet computers is potentially harmful to your neck muscles, leading to possible long-term neck pains. Because of its convenience, tablets are usually used in wrong postures as compared to desktops. As such, one should be careful in choosing postures when using tablets. A temporary convenience and comfort might have the price of a long-term pain.
References:
Anita N. Vasavada, Derek D. Nevins, Steven M. Monda, Ellis Hughes, David C. Lin.Gravitational demand on the neck musculature during tablet computer use.Ergonomics, 2015; 1 DOI: 10.1080/00140139.2015.1005166
Taylor & Francis. “Tablet use: significance of usage position, potential for neck damage.” ScienceDaily. ScienceDaily, 13 March 2015
What I find interesting is that people are very quick to blame neck and back injuries on technological advances and tend to forgot that there are cervical/thoracic injuries associated with reading books. In terms of how people look at and position themselves when using tablets is very similar to physical books (that is the point of tablets, after all). Ultimately, posture is the biggest factor in determining whether or not there is added stress placed on your neck and back, so education of proper posture will be the most effective in reducing these types of injuries.
ReplyDeleteAs I sit here, writing this comment after, I acknowledge my position and realize that it is exactly what this article describes and now I worry about my long term side affects because of it. I think that technology has many many negative side effects on our population but also many positives and if neck and back pains become an issue, not to sound snobby, I think there will be a cure by the time I need one if I do.
ReplyDeleteI think the possibilities of neck and back injuries due to being on computers all day are well documented, and yet people still go on ignoring them because these technologies are so ingrained in our daily life that it's seen as a necessary evil. What's more disturbing is seeing young people with rapidly growing bones and muscles succumb to these challenges. Our youth are using their technologies more and more now and it's causing serious changes in their development. This could lead to unforseen problems in the future. We need to be careful with our technologies and use them in moderation.
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