There was some interest in the replies I received to this query, so there
follows a summary. Many thanks to all who replied; delays in responding are due
to me catching up after a lengthy holiday, during which I considered ankle
proprioception in the context of trekking and climbing in Nepal!

Firstly, I shall describe more fully the work I am involved in. I am attempting
to measure movement at the ankle in order to assess ankle proprioception by
means of a repositioning test. As far as I am aware, there are only two reports
of measurement of ankle proprioception that have permitted (and measured)
movement in three dimensions (Feuerbach et al, 1994; Abboud et al, 1999) - I
should be very interested to hear of any other such work. I am using a Northern
Digital Polaris system, which works with collections of markers, referred to as
tools, rather than individual markers. The output of the system is given in
quaternion format (the recent BIOMCH-L discussion was of considerable interest
to me!), but I am planning to convert the results into standard roll, pitch and
yaw angles. I shall be investigating dorsi/plantarflexion and
inversion/eversion, but I need to place the "tools" such that the combined,
coupled movements about the ankle joint complex can be meaningfully described.
I should be delighted to continue to hear from anyone with similar interests,
or who can give pointers to previous work that I may not be aware of.

Kind regards,


************************************************** ****************

Original query:

I am using an optical tracking system to measure movement at the ankle joint. I
am interested in describing rotation at the ankle about a physiological axis of
rotation, and would be grateful for any advice on placement of markers on the
shank and the foot in order to do so.


Chris Monk

Chris Monk
Clinical Bioengineer
Department of Medical Physics & Bioengineering
Southampton General Hospital
Tel: +44 (0)23 80 795085
Fax: +44 (0)23 80 794117

************************************************** ****************


We have published a paper 2 years ago using an electromagnetic 3D goniometry
system, it might be of help to you, the reference is:
*The Development of a Three Plane System for the Measurement of the Ankle/Sub-
Joint Complex in Gait*, The Foot (1999), 9, 31-39. G C Rendall, R J Abboud

Dr Rami J Abboud, BEng, MSc, PhD, MIEEE
Master of Orthopaedic Surgery (MCh Orth) Course Director
Foot Pressure Analysis Laboratory/Clinic Director
TORT Centre, Orthopaedic & Trauma Surgery Department
Ninewells Hospital & Medical School, Dundee DD1 9SY, Scotland, UK.
tel:++44-(0)1382-496276 (Int. 36276), fax:++44-(0)1382-496347



The subject of my Master's thesis involves using optical trackers to
determine the location of ankle joint axes using optimization. I was
wondering what research and applications you are looking at. I've
attached a couple of short papers i just wrote which describes a little
about the trackers i use and my research.


cam shute


Dear Chris I have designed one electromechanic machine
wich is able to follow the physiological movements of
the leg ankle and foot.I was reading your mail, but I
can not understand which movement are you making
reference at.You call it "rotation". could you be
motre specific about the description of the reference
axis?.I would like to exchange information with you.


Dear Mr.Monk,

There has been a lot of publication from our lab using optical
tracking system Optotrak (Northern Digital Inc). If you have any
questions don't hesistate to ask.
Shortly: Put a marker on a foot one behind the toe and the other
below the ankle. The third marker should be placed at the ankle
joint and the fourth on the shank. Using the cosine sentence an
ankle angle can be computed.

Best regards,

Imre Cikajlo

Imre CIKAJLO univ.dipl.inz.el.
Laboratory of Biomedical Engineering and Robotics
University of Ljubljana, Faculty of Electrical Engineering
Trzaska 25, p.p. 2999, 1001 Ljubljana, SLOVENIA
tel: +386 1 4768 485
fax: +386 1 4768 239


Dear Chris,
you may find some help by going through the
Leardini A, O'Connor JJ, Catani F, Giannini S. Kinematics of the human
ankle complex in passive flexion; a single degree of freedom system.
J Biomech. 1999 Feb;32(2):111-8.
in case your is an in-vitro study, or
Leardini A, Benedetti MG, Catani F, Simoncini L, Giannini S. An
anatomically based protocol for the description of foot segment kinematics
during gait.
Clin Biomech (Bristol, Avon). 1999 Oct;14(8):528-36.
in case your is an in-vivo study.


Alberto Leardini, DPhil
Movement Analysis Laboratory
Centro di Ricerca Codivilla-Putti
Istituti Ortopedici Rizzoli
Via di Barbiano 1/10, 40136 Bologna ITALY
tel: +39 051 6366522
mob: 0347 3237634
fax: +39 051 6366561


Dear Chris

I noticed your mailing on the BIOMCH-L board, but I have been
unable to retrieve your posting.

I thought you might like to visit our website to see what intruments
we manufacture for ankle measurements, as it could be of
interest to you.

If you have any questions, or if you would like to receive a
copy of our product brochure and price lists, please let us
have a postal address.

Kind regards
Mary Wilding
Sales Office Manager
Biometrics Ltd
Tel: 01495 200800
Fax: 01495 200806
Date: 12 April 2001




We're looking at ankle torque range of motion of diabetics. So we're also
working on getting a joint angle around an axis of motion for each torque at
a time step. One idea I'm trying is to strap a plate to the bottom of the
foot and place my sensor there. Then collect data. I'm looking at how
"circular" the path is. I have several simple methods to do this. One I get
it working if you're interested I'll send it off to you. I'm using a
Polhemus system for the motion and our lab custom made force wand for
getting a force (into torque). Labview collects the wand's signal and I'm
working a on a custom VI with Visual C++ to display it all in real time.


David Giurintano
Paul Brand Biomechanics Lab
National Hansen's Disease Programs
1770 Physicians Park Drive
Baton Rouge LA 70816
(225) 756-3740 (v)
(225) 756-3745 (f)


You may find something helpful from the following artical:

Liu W, Siegler S, Hillstrom H, and Whitney K: Three dimensional, six-degrees-of-
freedom kinematics of the human hindfoot during the stance phase of level
walking. Human Movement Science, 16:283-298, 1997.


Dear Chris,

In this paper they developed a four-rigid body model of the foot and ankle.

" A System for the Analysis of Foot and Ankle Kinematics During Gait"
IEEE Trans. on Rehabilitation Engineering, vol. 4, N. 1, March 1996
Kidder, Abuzzahab, Harris and Johnson.

I f possible I would like to know your progess if you to try implement
it, and I would like to know what system you will to use.

I am usig ProReflex cameras (Qualisys) and would like to build this model.

Best regards,



How many cameras do you have? Really, the only consideration is that they
not the three markers on each of the shank and hindfoot not be collinear.
For example, shank could be anterior mid-tibia, anterior distal tibia, and
above the malleolus, while hindfoot could be posterior heel and two on the
side of the heel. Do you want a medial or lateral view? What activity will
subjects be performing? How do you intend to analyze the data? I am
intrigued by your goal of representing a physiological axis of rotation, and
wondered how you were going to mathematically represent this.


Samuel Lee, M.Sc.
Research Engineer
Hospital for Special Surgery
Department of Biomechanics & Biomaterials
New York, N.Y. 10021 U.S.A.
(212) 774-2382

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