This is a quick procedure to allow you to determine if there is any bias error in your Myo Tape. Myo Tape Reference, www.bodybuilding.com/store/acc/myotape.html Keep in mind that these measuring tapes are also made private label for other companys, so with the exception of color and logos they are all the same.
This started with the purchase of a new myo tape, as my old was started to tear at the plastic pin at the start of the tape. My new measurements were checking 1/8+ over previous measurements. I knew the new tap or the old tape were off, or a combination of both. I started by checking for tape stretch, but after lining up the tapes, there may be been at most a 1/16th off over a 2ft distance on my old tape. No big deal there. The culprit was where the plastic pin attached to the tape. They differed by 3/16". I assumed the tape itself was accurate and found a round container with a outer diameter that closely match the radius of the myotape body. I took measurements with both my myotapes, as before 3/16ths difference. I then retracted about 30inches of tape from the myotape body. I started with the 10in mark and measured around the same container previously measured. After comparing the results of this measurement with both of my myotapes and the normal measurement (using the tape pin attached to the myotape body) of the container. I was able to draw the conclusion that my new tape was measuring a 1/16th inch too big and my old tape was measuring 1/8th inch too small.
1) Find a cylinderical object or container that has an outer diameter that closely matches the radius of the myotape body. This is important, because if the object is too small in diameter, then your measurements will read big, and if your object is too big, your measurements will read slightly smaller. It is better to pick a container bigger than small though, as the maximum error is smaller if container is big as oppose to small.
2) Measure the container using your myotape using the instructions supplied with your myotape. Write this measurement down. For example, lets assume we measured 14-3/16"
3) Now retract 30+ inches of tape from your myotape. Starting with the 10-inch mark on the tape, wrap the tape around the container and take a reading of the tape at the 10-inch mark. Write this measurement down. For out example lets assume we measured 24-5/16".
4) Calculated the true measurement based on straight tape measurement. Since we took our reading at the 10-inch mark, we simply need to subtract 10" from 24-5/16". So our straight tape measurement is 14-5/16"
5) We can now determine our myotape bias error by subracting 14-5/16 from 14-3/16. Resulting in a bias error of 2/16" or 1/8".
So in this example our myotape reads an 1/8" short. Now, why this is not a true calibration in the since that you can correct the myotapes measurments, you do have a constant that you can alter your measurements with before recording them. I simply use a permanent marked and made note of the error on the myo tape body.
I all honesty there is not much need for this procedure, as any myotape, with or without error, will allow you to track gaines and losses which is the main purpose. In the case where you switch myotapes, or share measurements with others, this procedure will allow you to report accurate results and seemlessly switch myotapes without unexplained gaines or losses.
Thread: Calibrating Your MyoTape