View Full Version : Measuring body surface vibrations

Jacob Havkrog
01-25-2001, 10:02 AM
Dear Biomechanics list.

I would like to measure vibrations on the surface of the human body, and I
would very much like pointers, hints and comments on how to do that.

My name is Jacob Havkrog and I have a MSc degree from Aarhus University,
Denmark in computer science and mathematics. I've worked some years as a
software developer, but have now moved to England to study full time to
become a teacher of the Alexander Technique. Its a 3 years training course
and I'm in my 2nd year now.

In short, an Alexander teacher helps people to improve general body
functioning by improving the proprioception and posture. The main tool is
the teachers hands that are gently registrating the pupils body when quiet
or guided through simple movements like standing from a sitting position.

While the AT is well-recognised as a scientifically based method, I am still
struggling with understanding how an AT teacher can feel things in another
persons body, and especially how the teacher can influence a pupils
proprioception only through a gently touching hands.

What a teacher feels with his hands are vibrations in the body, small
posture adjustments that happen automatically all the time. It is quite easy
from the vibrational quality of a movement to judge if it is performed well.

This is what I would like to measure. Put in other words, I would like to be
able to record the 3-d trajectory of one or more points on a human body
while going from a standing to a sitting position, or other simple
movements. AND this measurement must be of a sufficient precision that
vibrations in the range of 1-100 Hz (?) and an amplitude down to 0.1 mm.

These figures (frequency and amplitude) are my guesses, what I'm looking for
is vibrations in a range that a sensitive human hand may feel. I believe
that such kinds of measurements can be of great value in the understanding
of the Alexander Technique.

Thanks for any reply. I will edit and post the replies if there is anybody
is interested.

Here is a link to the main regulatory body of the AT:


Jacob Havkrog, Brighton, UK

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