Being able to measure people and bikes is a core skill for those of us involved in bike sizing and fitting.
Why are we measuring? To record and document “before” and “after” changes; to project recommended bike sizes and models; to advise on fit components.
A bike can be described by its measurements, and the changes are relatively small from one size to another, and from one shape or model to another.
A person and their fit position on a bike can be described by measurements as well. Again, small changes can make for a big difference, which is why it is important to be able to measure consistently, accurately and reliably.
Much of the responsibility for accurate measuring has been passed onto technology. i.e., we believe what we see on a screen with data flow from video analysis and motion capture. However these systems are not infallible, and it helps to be practiced with hands on measurements, which are required if you are using an analog tool like the Fit Kit. A practiced human is more accurate than a poorly calibrated machine, and has the ability to interpret the numbers and have a good idea if a measurement is “off”.
As cycling season starts to get underway in much of the northern hemisphere, you may be dusting off your Fit Kit tools and getting ready to use them. Now is a great time to practice locating the key body measurement points, and getting a refresher in using the tools. Practice on different body types. Practice on other staff. Repeat the measurements on the same person 3 or 4 times over a few days, recording the information separately each time, and then comparing the variation at the end. You should be within a few mm each time.
If there is wider variation, explore why there are inconsistencies. The subjects clothing and posture, and your instructions and technique can all contribute to variation. Reduce the variations and improve the reliability of obtaining repeatable results. Measure twice, cut once is a good motto to keep in mind.