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Positioning the screen optimally is critical to minimising eye strain but also to maintaining good posture and managing back strain as one of the key reasons people lean in towards their screen is to view the screen, so let’s start with distance… &nbsp; How far should your computer screen be? &nbsp;'Arms length' is something you may have heard! &nbsp;Well, whose arms? &nbsp;Does this mean that people with longer arms have a better eye sight? &nbsp;And where does this guideline even come from and can it be used for everyone? &nbsp; Well the answer is no, of course not. &nbsp;There are a number of factors that influence optimum screen distance. &nbsp;Here are a few... · &nbsp; &nbsp; &nbsp; Visual acuity (eye sight) · &nbsp; &nbsp; &nbsp; Number and size of screens · &nbsp; &nbsp; &nbsp; Font sizes used · &nbsp; &nbsp; &nbsp; Amount of data viewed · &nbsp; &nbsp; &nbsp; Type of information on screen (images/characters/numbers) · &nbsp; &nbsp; &nbsp; Lighting · &nbsp; &nbsp; &nbsp; Number/length of natural screen breaks &nbsp; The arm's-length guideline most likely came from recommendations on monitor placement in NASA cockpits, which were associated with touch screen controls and are therefore based on reach distance. &nbsp;This guideline was extrapolated for use in other guidelines. &nbsp; &nbsp; However, the evidence for 15” screens suggests a comfortable viewing range of 45-75 cm, with an average of 60cm. &nbsp;Interestingly, if the screen is at arm’s length for most people, it naturally falls around the 60cm mark, so no need to throw the baby out with the bathwater. &nbsp; The thing is, 15” screens are largely a thing of the past and when we were using them, we didn’t have the array of applications that we have nowadays. &nbsp;Plus, dual and triple screen use was very rare, unless you worked in the investment banking world, so what should we be aiming for now. &nbsp; In general, with screen distance, further is better (up to our optimum viewing distance of around 120cm), however in order to take into account the limiting factors detailed above, follow these principles: &nbsp;Position the screen as far back as you can read the characters and maximize the font size as far as practicable for your role (you don’t want to cause RSI by increasing mouse scrolling to accommodate reduced information presented on the screen at one time). &nbsp; What about the screen height? &nbsp;Well, our optimum viewing distance is closer with a slight downward gaze, therefore a 30 degree downward viewing angle is recommended. &nbsp;A good rule of thumb is to position the top of the screen level with your horizontal line of sight.

Screen Positioning

Use of Swiss Balls in the office – Some evidencePhysio’s, doctors, orthopaedic consultants and other medical and rehabilitation professionals are frequently espousing the benefits of ‘improving your core stability’. Now, the definition of ‘core stability’, how we measure it and if training it has a positive impact on back pain more than other forms of exercise, is another topic for another time, but the question I want to consider here is, is sitting on a Swiss ball in the office beneficial? The primary reason that this is recommended by said professionals is to improve core stability and/or overall posture, as they ‘force you’ to sit correctly.So let’s look at some evidence...Improving core stability: A study in 2006 in the Clinical Biomechanics Journal [1] concluded that sitting on a gym ball produced no difference in trunk muscle activation than simply sitting on a surface without back support (i.e a bench or stool) and a more recent (2013) systematic review of a number of studies investigating the effect of dynamic sitting on trunk muscle activation in the Journal of Applied Ergonomics [2] concluded that there was no increase in trunk muscle activation with dynamic sitting in 5 out of 7 studies. Ofthe other 2 studies, one showed increase muscle activation with dynamic sitting but only in one out of eight muscles measured and the other showed increased muscle activation but also increased 'spinal shrinkage', indicating compression of the discs in the spine and increased pressure.Improving posture: A 2006 study in The Journal of the Human Factors [3] concluded that prolonged sitting on a stability ball does not greatly alter the manner in which an individual sits, yet it appears to increase the level of discomfort. (Note: a latter study showed that with a period of ‘accommodation’, discomfort levels improve, however posture still remains the same).Summary: So, is core stability improved when sitting on a Swiss ball? &nbsp;Not really. &nbsp;Is posture better, no, posture is the same and reported discomfort is greater, initially, though this improves with a period of accommodation or adaptation.So, what are gym balls for? Exercise, rehab, strengthening. They are gym equipment and can certainly help you to be fitter, stronger and more injury resistant if used as part of a targeted exercise programme, but the principle of good workplace/office ergonomics is to minimise physical demands and musculoskeletal loading and reduce effort. If someone is unfit and/or generally inactive, trying to 'force' increased activity by increasing postural demands is ineffectual at best and detrimental at worst.Note this is simply an opinion based on a small amount of research. It is not a systematic review of all the evidence and is not definitive. This is a topic, which divides opinion in many cases and any decision to use or not use a Swiss ball in the office, should be taken in the context of what is practicable in the specific office environment and following discussion with healthcare professionals, who will offer their opinion on the matter, thereby allowing a balanced view. &nbsp; &nbsp; &nbsp; References <a data-mce-href="https://www.clinbiomech.com/article/S0268-0033(05)00275-5/abstract" href="https://www.clinbiomech.com/article/S0268-0033(05)00275-5/abstract" title="Clinical Biomechanics" target="_blank" rel="noopener">1. &nbsp; &nbsp;S.M. McGill, N.S. Kavcic, E. Harvey., 2006. Sitting on a chair or an exercise ball: Various perspectives to guide decision making. Clinical Biomechanics 21(4), p.353- 360</a> 2. &nbsp; <a data-mce-href="https://www.sciencedirect.com/science/article/abs/pii/S0003687013000161?via%3Dihub" href="https://www.sciencedirect.com/science/article/abs/pii/S0003687013000161?via%3Dihub">&nbsp;Kieran O'Sullivan, Peter O'Sullivan, Mary O'Keeffe, Leonard O'Sullivan, Wim Dankaerts., 2013. The effect of dynamic sitting on trunk muscle activation: A systematic review. Applied Ergonomics 44(4), p.628-635</a>3. &nbsp; &nbsp;<a data-mce-href="https://journals.sagepub.com/doi/10.1518/001872006776412243?url_ver=Z39.88-2003&amp;rfr_id=ori:rid:crossref.org&amp;rfr_dat=cr_pub%20%200pubmed" href="https://journals.sagepub.com/doi/10.1518/001872006776412243?url_ver=Z39.88-2003&amp;rfr_id=ori:rid:crossref.org&amp;rfr_dat=cr_pub%20%200pubmed">Diane E. Gregory Nadine M. Dunk Jack P. Callaghan. Stability Ball Versus Office Chair: Comparison of Muscle Activation and Lumbar Spine Posture During Prolonged Sitting. Human Factors 48(1), p.142-153</a>

Stability Balls in the Office

Breaks 31 Jul&nbsp; How important are breaks from your computer?“Take breaks. &nbsp;Little and often. &nbsp;Ideally every 20-40 minutes”. &nbsp;This is a familiar mantra espoused by health and safety professionals; therapists and others concerned with the well-being of colleagues and clients using computers for long periods in their occupation. &nbsp;Why? &nbsp;Does the evidence support the dogma?Sitting has been demonised over recent years, with hyperbolic statements like ‘sitting is the new smoking’, being used to grab headlines and sell standing desks; however, it is not without reason that this concern has risen. &nbsp;Sedentary lifestyles have been linked to a number of serious health conditions, including ‘all-cause mortality’, and although these risks reduce with exercise, the ill-effects of sitting for more than 8 hours per day, are not sufficiently compensated by exercise and those that sit for 9-11 hours are at particularly high risk. &nbsp;This is, and should continue to be, the main drive for incorporating breaks from computers, to reduce overall sitting time in the day, with a goal of getting below 8 hours (including the commute and sitting at home); however, we typically consider breaks more often, in their role in preventing aches and pains or musculoskeletal (MSK) disorders.This is because symptoms such as back pain are immediate and people are more easily influenced and concerned by short term risks than, comparatively, more serious but slower developing, long term issues. &nbsp;So, we will focus on this here and the questions I want to explore are:&nbsp;<ul><li>Do breaks prevent MSK disorders in those that have no issues (are pain free)?</li><li>Do breaks reduce symptoms in those that have MSK disorders already?</li><li>Does the activity undertaken during breaks, make a difference? </li><li>Is there an optimum frequency and/or duration of breaks?&nbsp; &nbsp;</li></ul>So, let’s look at some evidence…One great source of evidence is the Cochrane Library, which is an independent group that publishes ‘systematic reviews’. &nbsp;This means that they explore the research on a given topic, and evaluate this in terms of the quality of the studies and the results, and then provide some conclusions. &nbsp;In 2019 they carried out a review of the impact of differing work break schedules on the prevention of MSK symptoms in healthy individuals. &nbsp;A full text of this review can be found <a data-mce-href="https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD012886.pub2/epdf/full/en" href="https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD012886.pub2/epdf/full/en">here</a>. &nbsp;I would recommend jumping to the plain language summary, starting on page 4. &nbsp;Essentially, my main takeaways from this are…In healthy workers (and this is key, the studies only included people with no symptoms), there is no significant difference in the incidence of MSK disorders when additional breaks are taken, though, interestingly, additional breaks (30 second passive breaks every 20 or 40 minutes) may improve productivity and work performance. &nbsp;The frequency of additional breaks (high or low), also made no difference and when comparing the type of break (active or relaxation), again, no differences were found. &nbsp;None of the studies reviewed looked at the length of breaks specifically.&nbsp;Remember, these conclusions don’t mean that breaks do not prevent MSK disorders, just that there is no high quality, repeatable clinical evidence for this, at the present time. &nbsp;Some studies, including one from the International Journal of Research and Public Health in 2018, demonstrate increased discomfort with sitting at a computer, surmising that hip and thigh discomfort generally becomes significant at around 90 minutes and lower back pain at around 2 hours. &nbsp;There is evidence that this impacts cognitive function and productivity, but no evidence that this leads to long term issues. &nbsp;A longer study in the American Journal of Industrial Medicine, spanning 4 weeks, looking at data entry workers, who were given an additional 4 breaks of 5 minutes duration, per shift reported reduced discomfort and eyestrain and also showed an improvement in data-entry speed so that overall productivity was maintained. &nbsp;There are no long-term studies investigating breaks or the lack thereof in the prevention of MSK disorders.What about for those already in pain?Another systematic review of research conducted in the Journal, Applied Ergonomics, in 2018, showed that there were some positive benefits of breaks for managing discomfort though the quality of the research was low. &nbsp; Better quality research demonstrated that active breaks, including postural change was more effective in managing pain and discomfort than passive ‘relaxation’ breaks and, encouragingly, that breaks had no detrimental impact on productivity. &nbsp;It should be noted that the maximum study length was 2 hours with break times ranging from 20 seconds to 30 minutes, so whether or not this information can be extrapolated over a day, week or months, is unclear.Is there an optimum frequency and duration?This is a tricky one as there is little research looking at this. &nbsp;One study in the International Journal of Industrial Ergonomics, done back in 1997, looked at a couple of break schedules over the course of a working day, measuring stress via ‘psychophysiological monitoring’ (sweating; temperature etc.) as well as discomfort and muscular strain. &nbsp;They concluded that more frequent shorter breaks (7-8 minutes every 50) were more effective in the morning, but longer, more infrequent breaks (15 minutes every 100) were better in the afternoon. &nbsp;They also noted that stress measures may have increased as a result of the rigidity of the break schedules, so some flexibility over when breaks are taken is probably useful.&nbsp;To summarise…&nbsp;The research seems to be pretty clear: that taking breaks improves productivity or at least does not cause any detriment, so if for no other reason, than to improve your productivity, you should try to incorporate breaks.If you are currently pain free, then a lack of breaks will likely lead to some physical discomfort, but this is unlikely to be a major factor in any long-term musculoskeletal difficulties. &nbsp;Age, lack of exercise, nutrition, genetics, poor sleep and other factors are far more relevant. &nbsp;The speed of onset and severity of symptoms will be affected by the ergonomics of the workstation, including the adjustability and comfort of your chair and the height of your screen and you should move whenever you experience symptoms. &nbsp;These are most commonly felt in the hips, buttocks and lower back but also the upper back, neck and shoulders. &nbsp;Upper limb problems are less common but can be equally severe and debilitating if ignored early on.If you have persistent symptoms, then breaks are more important. &nbsp;Short frequent breaks in the morning and longer, less frequent breaks in the afternoon seem to be preferable and you should incorporate movement. &nbsp;The ability to work in different postures, such as standing (sit-stand desks) may be of benefit, but this does not negate the need to move.Regarding the frequency of breaks, the optimum is unclear as there is little research looking specifically at this and it is probably related to a number of factors, including individual attention span; the nature of the work and how well it lends itself to breaks; visual demands of the work and duration of the shift, among other factors. &nbsp;As above, letting symptoms be your guide is probably not a problem with regards to managing musculoskeletal strain, however there are productivity benefits to taking more regular scheduled breaks.The most important reason for taking breaks is the prevention of long-term health issues associated with sedentary behaviour – sitting for more that 11 hours per day. &nbsp;If you have an hour commute to and from work and sit for at least an hour in the evening at home, then you only have to remain seated for 8 hours in the office to hit the 11 hour mark. &nbsp;Given that many office roles exceed an 8 hour day and the lunch hour is now closer to 30 minutes on average and is typically spent seated for the majority of the time, finding ways to not be seated at work is critical. &nbsp;This is probably the best case for purchasing a height adjustable desk, but justifying the cost as a preventative strategy is usually far more difficult than if managing acute difficulties that are immediately impacting quality of life and work...

Evidence for Breaks

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