Well, it is the way that limbs and joints are measured so that a consistent picture of the population is developed.
In the US furniture standards were first developed after World War II, when there was a large databank of physical characteristics of soldiers. The standard table height and chair height is still designed to fit the average World War II soldier. Since then, the Army has continued to keep data. They update their statistics regularly.
Data on physical size (hand size, digit length, palm girth,arm length etc) is used for everything from designing tools to making clothing. They also may be used to determine workstation or chair fit. Often, a visual is sufficient. When a good view is not available, the proper measurements can help.
It’s interesting that human populations show significant variation over historical time depending on where they dwelt. They tend to follow Bergmann’s rule: individuals in cold climates tend to be larger than those in warm climates. They also follow Allen’s rule: individuals in cold climates have shorter, stubbier limbs.
Theoretically, this has to do with “surface to air” concerns. In cold climates, you want as little skin as possible exposed to air. In hot climates, the more skin the better.
Needless to say, these are generalities. You might expect that the Chineese population is short but the Guinness World Record holder for height in women in 2010 was Yao Defen at 2.33 m (7 ft 7 1⁄2 in).
Here are some averages for the United States.
Average Heights in the US:Measured between 2003 and 2006
| Category | Average Man | Average Woman |
| All Americans 20 + | 5 ft 9.5 inches | 5 ft 4 inches |
| White Americans 20 - 39 | 5 ft 10.5 inches | 5 ft 5 inches |
| Black Americans 20 - 39 | 5 ft 10 inches | 5 ft 4.5 inches |
| Mexican Americans | 5 ft 7 inches | 5 ft 2 inches |
It’s obvious that something built to fit most white men will NOT fit most black women – or white women for that matter.
5 inches difference in height is a lot. It’s the difference between being able to see your face, neck and shoulders in a mirror and only seeing your eyes (I found this out when my brother installed my bathroom medicine cabinet. I still have a great view of my eyes.)
Even among Americans there is a wide variability. How can a manufacturer fit everyone with one product?
The Answer: He Can’t !
What’s Important in Size
For some things, size is not really a great concern – consider one-size fits all clothing (sometimes one size really does fit all – but even here there is a rage that it fits best). Choosing the average size won't work. If you do that, you've left out 90% of the population.
It’s important that some things fit very well – like shoes, a slinky dress or a ring. I put chairs and desks in the same category.
Like shoes and the dress, if you’re using them for dress down short term wear, the fit of the desk and chair may not be that important. If your’re going out for business or looking at long term use, good fit becomes imperitive.
Ill fitting shoes can give you blisters and corns, even bunions, knee tendinitis or planter fascitis over time. A badly fitting chair or desk can result in back, neck and shoulder aches. If the chair is not low enough and you aren’t using a foot-rest, there are even more potential problems.
What is a poor businessman to do?
The Business Solution
Businesses consider that a good ergonomic product should fit 80% of the population. Either through making the product adjustable or through exceptionally good design they have something that will work reasonable well for everyone except the 10% of the population that are smallest and the 10% that are largest.
This is good news for most of us. For those that are outliers you may need to resort to specialty vendors.
As far as chairs go, most good manufacturers have sizes that will fit an even larger proportion of people - just about everyone, from big and tall or skinny and tall to very petite.
Desks and tables are a different matter – and if you have a chair that fits and a desk that doesn’t, you are totally out of luck! Unfortuately, you use the two as a unit – not separately. If the chair fits but you can’t reach the desk top without hunching your shoulders, or you have to crane your neck to see the monitor you are still in trouble.
Thankfully, there are solutions, but you may need an individual office evaluation to come to the best compromise. There are ergonomists who specialize in home office or business office evaluation. Some work off photos of you in the work environment (fairly good). Some work of videos (better). The value of the evaluation depending on the ability of the person focusing the camera to include everything needed.
In dealing with ergonomics, there are many aspects of the work and the work setting that may not be obvious in pictures or video. Also, while you are demonstrating your work, it is more likely that the angle of view will not show everything needed in photo or video. In-person visits are of course the best and generally the most expensive.
If you need to economize, check your local University for students with some experience who could benefit from using your workstation evaluation for a class project or paper. Although it may not be a top-notch evaluation, your work process and workstation should improve enough to make a strong positive difference.
For some interesting experiments in Anthropometrics, go to
http://jcflowers1.iweb.bsu.edu/rlo/anthropometrics.htm
