How to Know if You’re Measuring the Right Body Part

Jun 16th, 2017


When it comes to developing almost any product to be worn or used by humans – whether it is the development of a virtual reality headset, a seatbelt, a truck cab or anything else – it is important that you do due diligence to make sure the product will work properly; it will only work properly if the product’s fit doesn’t impede its function.


Believe it or not, it can be easy to mis-identify what needs to be measured. When I was visiting my grandkids in Minnesota over the holidays, we were deciding who should be in the backseat of the car between the two car seats. As I had the smallest derriere, I was shooed to the backseat. This didn’t work so well because the car seats were wider at the top than their base, and my shoulders were quite smashed between them. Quick measurement guess = an uncomfortable car ride!


The Not-So-Obvious Measurement


Measuring body parts for use in product design can be complicated… if you don’t know exactly what you are doing. A common mistake is measuring the wrong body part. Remarkably, this can happen fairly frequently, and ill-fitting products are hitting store shelves all the time as a result.


The right body part to measure for some products might seem obvious. And sometimes, it is. For example, for virtual reality headsets, one of the key things to measure is the diameter of potential customers’ heads. But for other products, what may seem like a sure-thing simply isn’t.


Here’s an example. Someone once called me asking for data on hip dimensions. They were designing a rescue boat that needed to fit a certain number of people. This person figured that hip dimensions would be best to measure since he was thinking only about the seat itself. However, this was an incorrect assumption, and one that could have led to boats that could not properly fit their intended number of occupants, had this measurement gone forward. Bideltoid breadth, the dimension from the side of one upper arm to the side of the other, is actually wider, and that was the right measurement for this particular project.


More to Consider than Which Body Part


Let’s say a product developer worked with a physical anthropology expert and is positive they have the correct body part to be measured for a particular product. Are they on track to developing a product that fits just right? Possibly, but there can be more to it. Not only do developers have to consider body dimensions, but they also have to consider body capabilities, such as reach and effective reach.


As an example, let’s say someone is developing an assembly line, including belt, bin attachments and controls. The developer has probably determined how far a worker can reach in order to appropriately place the bins and controls on the conveyer belt. Measuring arm reach is a starting point, but in this case, because of the product’s intended use, it isn’t enough. Heavier employees will be standing farther away from the conveyer belt because of their protruding stomachs, so their effective arm reach would not be the same as their arm reach. Both must be accounted for in order for the product to work well for all its intended users.


Recreating Measurement Offers Additional Challenge


Once you have good data about the population you are designing for from anthropometry experts like those at Anthrotech, you are well on your way to developing a product that fits. Still, there can be another challenge. Once a prototype is developed, it is usually a good idea to test it on living, human test subjects. Measuring the critical dimensions on test subjects will ensure there is a representative range of people to match a target population. However, it is vital that you use exactly the same techniques to measure the test subjects as were used when the target data were originally collected. If the measurement is done incorrectly, then you really aren’t measuring the right dimension in the right way, and the results will be inaccurate.


Certainly there are challenges when measuring populations for product development. There is much room for error, and errors in this area result in poorly-fitting products. The good news is that anthropometry experts have faced these challenges time and time again. We know exactly what we’re looking for and can help product developers pinpoint the right body part – accounting for the ways that body part will be moving when using the product – and ensure that any and all measurements completed are uniform and accurate.

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