PDA

View Full Version : Re: Effect of frontal and transeverse plane crosstalk on Sagittalplane kinematic and kinetic data



David Smith
10-20-2006, 08:58 PM
Barthi

Would you like me to email a paper I wrote for my MSc applied biomechanics
on a similar subject. It looks at normal V's Genu valgum gait and the errors
and limitations associated with the gait analysis.


There can be massive errors associated with 2D saggital plane gait analysis
when compared to 3D analysis. This includes qualitative and quantitative
analysis. When the gait style is unusual this is much more compounded ie CP
and hemiparetic gait where there is lots of frontal and transverse plane
motion going on.


The knee is one of the most difficult joints to reliably characterise in
terms of kinetics and kinematics and the system and protocols of analysis
must be extremely robust and reliable and leave little room for ambiguity.
2D analysis cannot achieve this even though it can still give some useful
data.

I'm just writing another paper on the limitations of gait analysis in
general if you would like to view that when its finished?

Two books I have found very useful are:

Gait analysis in normal and pathological gait, Perry J (Rancho Los Amigos)
Slack Inc.

Biomechanics and motor control of Human movement Winter D A wiley
Interscience New York.

In 3D analysis a lot of effort goes into identifying joint local axis and
characterising joint centres of rotation, The location and centre of
rotation defines the motion of the segment for a certain Joint angular RoM.
This is not usually the case in 2D analysis where the joint axis is usually
assumed to be aligned with the global axes frame of reference.

For instance 3D analysis might identify 30dgs of knee flexion but also 45dgs
of hip external rotation. What would the knee flexion look like from the
saggital plane point of view, perhaps 15dgs flexion?? and how would you see
the external hip rotation if the foot was internally rotated by 20dgs. Then
what if also the knee local axis is 10dgs rotated in the frontal plane how
will this affect RoM of the shank segment perhaps some apparent adduction in
relation to the thigh. But this is not adduction in terms of the local knee
axis. The same problems only more so appear in the ankle, STJ and MTJ where
the local axes are extremely oblique.

Gait analysis is a minefield of illusion waiting to trap and confuse the
unwary.

Cheers Dave Smith

----- Original Message -----
From: "Bharti Rajput"
To:
Sent: Friday, October 20, 2006 4:23 PM
Subject: [BIOMCH-L] Effect of frontal and transeverse plane crosstalk on
Sagittal plane kinematic and kinetic data


> Greetings Mailbasers,
>
> Was wondering whether anyone has some ideas on what effect
> frontal/transverse plane crosstalk can have on Sagittal plane kinematic
> and
> kinetic data. e.g. the effect of knee abduction and adduction on ankle
> dorsiflexion and plantarflexion.
>
> Much appreciated,
>
> Bharti Rajput.
>
>
>
> Bharti Rajput
>
> PhD Research Candidate
>
> Institute of Motion Analysis & Research
>
> Section of Orthopaedic & Trauma Surgery
>
> Ninewells Hospital & Medical School
>
> Dundee
>
> DD1 9SY
>
>
>
> brajput@aol.com
>
> b.rajput@dundee.ac.uk
>
> 0044 7711 621 456
>
>
>
>
>
>
> ---------------------------------------------------------------
> Information about BIOMCH-L: http://www.Biomch-L.org
> Archives: http://listserv.surfnet.nl/archives/Biomch-L.html
> ---------------------------------------------------------------