Wednesday, January 06, 2010

What You "SEE" Is Mostly Artifact! What's Underlying Skin Makes the Difference!

What you see in motion analysis is mostly


When you watch a human pedal, you are observing the motions? Not really!

True one can claim that the analysis becomes a scientific investigation, but it's not what it seems.

Commercial system can achieve accuracy, however the body is not rigid bodies and anything placed on the skin surface moves relative to the underlying bone during activities "Soft Tissue Artifact".

It is being proven to be a major source of errors in skin marker-base joint motion analysis. It is especially destructive in rotational and translational component of the knee where detecting deficiencies is key!

This is why we didn't come up with a Soft Tissue Artifact system for our dealers 8 years ago!!!

It doesn't matter the "cool factor", skin is moving a lot! Think about the short over the hips!

It is very important to know that the many tissues under the skin are limited in stretch! Even the compression of the joint and the shearing and its tension needs to be better understood!

We are very close bringing you that much needed information. Life is short and we want you to ride for the rest of it! That means we all have different levels of needs.

All the guess work needs to go away, even if the shops who make money off of it don't like it.

We intend on myth busting this stuff!

Too many people pay for a fit because its the only show in that shop, are told its the best, get the wrong fit, then later wonder what they got? They did pay for a fit service and they did spend a few hours on the fit, but what was done?

Was the bike sold to them because it fits or because it needs to be sold? It's more about closing the deal! Don't let them go to the next shop!

A very real issue! Who really knows the pedal strokes? This is not like walking or running! But many of these ideas that don't hold water for pedaling are being coached. It's not the same game and the muscles are not used the same.

That is why we used a $40,000 Noraxon sEMG tool about 6 years ago to go within and obtain better understanding, then later wanted all the dealers to Dartfish to teach the stroke. The problem here, is who is looking at the Dartfish and how do they see things?

All of our engineers didn't trust what has been written. Books are more about "good ole boy" than you know.

Today the tools and science is light years ahead of those books and under funded schools. Most of things that are taught in school is used as a base. Most schools don't have the money in the dept., to have the leading edge tools.

This happens a lot, someone goes to a school and they learn and earn a degree with great passion and they will "go to war" with what they know to be true, well informed on old tools that are not up to speed.

This is a major problem with 3D, the problem with anything placed on the skin to track motion. Things move a lot!

The preparative procedure like placing any thing on the highly mobile skin is going to look cool, but the skin marker-based stereophotogrammetry technique for human motion

analysis accuracy is mainly limited by soft tissue artifact, which reflects the non-rigidity of human body segments during activities.

It is critical to understand the 4D behavior and characteristics of soft tissue movement (line-of-pull, rotations, and range of motion)

in terms of the positional and orientation's change between different joint locations vs. skin locations.

Inter-marker movement exhibited similar patterns (bone shapes) and has inter-subject similarity, which is contrary to the prevailing opinion.

This insight allows us to perform better compensation strategies over skin marker-based motion analysis.

Wait until we release this year some very useful inter-marker analysis!

The game will change again!

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