“To Arm Rest or Not to Arm Rest… This is the Dilemma!”

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November 2015: Ergonomic chairs

During my presentation last week at the National Ergonomics Conference and Exposition where I presented “Chair Fit or Failure”, an audience participant asked me what my opinion was on the use of armrests while I was demonstrating how to measure a person in a chair for best fit. Before I could answer, he gave his opinion. “I usually remove them. Don’t they encourage leaning on them and isn’t that unsafe?”

I wasn’t surprised by his comment because many people think the same way and I have heard this from others over the years. But is this really true? Is it bad to use your armrests? I call this an “ergonomic myth or half-truth”. Let’s break down the history and research on chair armrests and the validity on whether they are good to rest on and use or not.

Historically, armrests have been on chairs for hundreds of years. Think back to the King and Queen’s throne where their typical sitting posture always included the use of armrests to rest the upper extremities. Typically, the Board of Directors all sit at the board room table in chairs with armrests. Or the chair at the head of a table often has armrests. In these cases, armrests act as status symbols for executives or the head of the household. So, if they are bad for us, why would we be using them for so long for hundreds of years ingrained in our culture?

Recent research in the last 25 years has validated the importance and use of armrests at a computerized work station. The research is quite clear on the value of armrests and in my clinical ergonomics experience, they are critical and important in the prevention of musculoskeletal disorders to the upper extremities. But there is one caveat… THEY MUST FIT TO BE BENEFICIAL!

The research cites a number of studies justifying the benefit of armrests with computer use.

Peter Opsvik, a Norwegian industrial designer best known for his innovative and ergonomic chairs and author of “Rethinking Sitting” articulates in his book, “ how when we are seated, our arms require both freedom to move and lots of opportunities for support”. He further states three primary reasons why our arms need support:

1. To ease the load placed on the back by the weight of our arms and hands.
2. If we are to use our hands to carry out an activity, some form of support can in many cases reduce the strain on the muscles that results from holding our hands in the area where the activity is to be carried out.
3. Having support for our hand and underarm can also provide more strength and precision for the work that is to be done.
Mr. Opsvik also states too much support can also lead to passivity and can be detrimental. “When we sit we instinctively try and find a place to put our arms and if we don’t have armrests, we use our laps. But if the chair has armrests, these are a natural place to find support”. He recommends the support be vertical beneath our shoulders to take body weight off of our backs.

In another study by Rani Lueder, “Impact of New Input Technology on Design of Chair Armrests: Investigation on Keyboard and Mouse”, from the 1996 Proceedings of the HFES Annual Meeting, the study investigated the effects of a mouse input device on the design of chair armrests. This study found height and rotational adjustable armrests provide superior forearm support during mouse use. For keyboard work, armrests reduced neck and shoulder fatigue. This finding validates Mr. Opsvik’s findings above in statement #2 and #3. Mouse use is a precision task and benefits from forearm support for better hand accuracy.

In 1999, Ms. Lueder also wrote with Paul Allie in “Chairs with Armrests: Ergonomic Design Issues”. In this review, Ms. Leuder identifies a number of important reasons to use armrests.

1. Armrests relieve loads on the neck, shoulders and arms.
2. Armrests may help promote good postures.
3. Armrests alleviate stress on the back by reducing about 10% of user’s body weight.
4. Armrests alleviate stress on the lower limbs and help to facilitate rising from a chair cutting hip forces in half.
5. Armrests help prevent excessive pressures on the seat.
6. Armrests stabilize posture and help us do our work.

Dr. Alan Hedge of Cornell University wrote in 2002 for “Work Healthy” online newsletter further reiterating the benefits of chair armrests by noting how armrests can reduce the static loads on muscles of the neck, back, shoulders and arms especially when the arms are extended forward or abducted sideways. He also states that finger forces are lessened when a user’s arms are supported while keying. Dr. Hedge concurs with Lueder’s findings that chair armrests help to stabilize the body when seated and are critical in rising from a chair to reduce knee and hip joint muscle forces.

Dr. Hedge also suggests with keyboarding and mouse use, armrests are not a substitute for a good quality keyboard tray system. It is acceptable to occasionally rest the arms at the elbows but be cautious of resting the forearms on the armrest for any prolonged period of keying and mouse work because this can compress the finger flexors or ulnar nerve. Armrests should be used for intermittent, light support with these tasks.

In one final study I want to point out by Fred Gerr in 2004, “Epidemiology of musculoskeletal disorders among computer users: lesson learned from the role of posture and keyboard use” states, “It appears that lowering the height of the keyboard to or below the height of the elbow and resting the arms on the desk surface or chair armrests is associated with reduced risk of neck and shoulder MSDs”.

Now that you know the facts on armrest use, I’ll return back to the comments from the audience last week. It might be the person asking me about armrests had not been exposed to a chair with good fitting armrests. That’s because, in my opinion and experience, most employers aren’t buying chairs with armrests that fit even 50% of their workforce. So they remove them. If armrests are fixed in position or limited in height, width, and/or pivot, then they most assuredly won’t fit correctly and can’t be used properly by a majority of employees resulting in awkward side leaning or interference so often reported. When this happens, the most reasonable action is to remove them eliminating any possible benefits reported.

The bottom line is fully adjustable armrests (height, width, pivot and forward/back glide) on a good ergonomic chair are an important part of an ergonomically correct work environment promoting a healthy and productive workforce.

Thank you for reading WIN NEWS blog.


Comments

Your Comments

Steven Garske

Greetings. Please allow me to join in the “To Arm Rest or Not to Arm Rest… This is the Dilemma! I enjoyed all of the previous comments and thought I would add a few comments from my clinical experience in ergonomics (25 years) as a physical therapist (30 years). There is no absolute rule regarding use of arm rests. The choice to support or not support depends on the individual situation including posture, available support, task, duration, required movement patterns and many other factors. If the client has enough mobility to place his/her spine into a neutral position (neither flexed, nor extended) and can rest their shoulder blades back and down on the back of their rib cage, then the weight of the arms can be distributed into the rib cage instead of the neck/spine. If they can maintain this position while performing their desired tasks, then this would make them a good candidate to function without arm rests. Of course lack of endurance to function in this posture could be a factor that requires support

If the client is not able to get into or function in the neutral position, then they will need support such as arm rests that fit them appropriately to offset the weight distributed into these areas while still allowing them to work. Alison did a nice job of pointing out the necessity of having a properly fitted chair. Arm support must also fit for rest, but also allow efficient movement of the required tasks. Time, reach distance, fine motor vs. gross motor movement patterns and equipment have to be considered too.

Arm supports, desktop, keyboard trays and other surfaces can encourage leaning (vs. just support), which can cause problems of compression at the ulnar nerve at the elbow, median nerve at the carpal tunnel and/or neurovascular entrapment at the pectoralis minor, (a muscle under the large pectoral muscle that originates from ribs 3-5 an attaches to a piece of bone (coracoid process) that is part of the shoulder blade). This can cause symptoms in one or more of the 3 nerves that travel all the way down to the hand and can mimic carpal tunnel syndrome or cubital tunnel syndrome or radial nerve entrapment. Having arm rests can have a “magnet effect”, encouraging clients to lean on something just because it is there.

Regarding the car seat evaluations and situations that arise including sitting in a “bucket seat” which is like sitting in a hole, encouraging the pelvis to tip back and causing the spine to flex and the head and shoulders to go forward. This situation must be addressed before arm support as you must take care of the foundation first. Forward extending head rests are a postural problem causer. I often recommend clients try placing a vertical support against the back between the shoulder blades to move the rib cage forward, the shoulder blades and shoulders back while causing less forward head position. Of course, this not meant as a substitute for medical advice and should be cleared by the client’s health care professional before implementing.

Thomas Rowell

The chair arm comment is very interesting. Recently I did a number of “car ergo assessments” (yes, you read that right). I found a Jeep with a petite female driver provided NO arm support. I found a Ford F150 with a large male driver could only support his left arm on the door arm-rest. In both cases the drivers had very long commute to work (an hour or more each way). I suggested they both take bath towels and roll them up to make a mock arm-rest. This is only intended as a temporary trial to see if good arm support provides relief from upper back and shoulder discomfort. If the towel works they should go find a similar size and appropriate shape pillow to place under their elbow and proximal part of forearm. They should be cautious not to inhibit steering function. I have been an advocate of properly adjusted arm-rests for 25 years with adult arms weighing 10-12 pounds why would you statically load the shoulders for 8-10 hours per day while working at a keyboard and mouse? Proper fit is key. We must also take personal preference into account. Some people simply don’t like arm-rests. If you don’t like them, lower them out of the way. Thanks for the article!

Alison Heller-Ono


In reply to Elizabeth, Thank you for your correction and thoughtful comment regarding Queen Elizabeth and her husband Prince Philip. I appreciate the correction… no disrespect intended to either party. It didn’t even dawn on me that I misrepresented Prince Philip as King… my use of their image was to show the history and use of armrests over the years and the hierarchy/status symbol of chairs

In reply to Kathy Espinoza. Thank you, Kathy! Keep reading and commenting… love to hear from my readers!

In reply to Mac Reynolds. Hi Mac, Thank you for reading WIN NEWS and your comments. I haven’t studied vehicle seats much but I’ve done hundreds of chair fittings. I like your comparison though. In a vehicle, the right side typically has a console used for arm support and the door has the left armrest typically, but it would be interesting to see how the vehicle designers determine placement, length and positioning of these supports.

Elizabeth Murphy

Prince Philip is not the “king” of England. At the moment, and for the past 65 years, the UK has had a queen: Queen Elizabeth II. Philip is her cousin and husband, and he has a bunch of titles, but not king. The last king was Elizabeth II’s father. Nice summary of the literature. Thanks!

Mac Reynolds

Very interesting reading this comment on arm rests and there was no mention of arm rests in the automobile. I use the arm rests in my car all the time with the express purpose of taking the load off my shoulders and back when driving. I can’t say that it helps my driving posture very much because the Head Restraint prevents me from using a more upright (not erect, just upright) posture. The arm rests in cars is needed by everyone, in my opinion, but its design is complicated by safety, ergonomics and comfort. In the US, the Head Restraint is a good example of the difficulties imposed on design by the desire to build a car interior that is safe rather than one that is ergonomic, comfortable and safe. I think that arm rests might possibly encounter the same problem, but currently there are no digital human models in use by the industry that sit in a seat to simulate the driver in position to operate the car. Either the DHMs are used for seat design to calculate pressure distribution or they are used for ergonomic reach and vision. All of these ergonomic models depict drivers sitting, just not seated. There is only one model that includes the seat, reach and vision in the optimization needed to design (or evaluate) a vehicle interior for the driver. And, I regret to say that it does not include an armrest. I greatly appreciate the current discussion because it points out the value of arm rests in any seated workstation.

Alison Heller-Ono

You’re absolutely right, Cindy! Thank you for pointing this important benefit out. I did mean to include this as well. With an aging workforce, weak knees and hips as well as obese workers, armrests are critical to help us lower ourselves into the chair as well as rise from the chair effectively by giving us something to hold onto. In addition, this keeps the chair from rolling out from under us preventing a fall! Thanks for your comment and for reading WIN NEWS, Cindy!

Cindy Burt

Alison: Very nice synopsis of the value of armrests. They are also very useful to help weaker individuals get into and out of the chair more safely.



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