View Full Version : Re: marker placement in gait analysis

Dr. Chris Kirtley (kwok Kei Chi)
07-11-1999, 12:00 PM
Dear Janina,

My final year students did this last year. They looked at 20 people
tested repeatedly in the same session (with the same marker placement)
and then again in a different session (with a new marker placement).
You'll find the standard deviations, coefficients of variation and
intra-class correlation coefficients, and a detailed description of the
marker placement (with pictures) at:


Basically, they found that sagittal plane angles and kinetics are OK,
but that some of the frontal and transverse plane angles and most of the
kinetics in these planes were unreliable.

Our method for standardised placements involves using a mirror
(described by Jeremey Linskell in Dundee) to confirm that the thigh
marker is co-aligned with the hip joint (trochanter) and knee joint
marker. These days I also do a check VCM plot after a single trial to
see if any minor adjustments (usually of the thigh marker, but also
occassionally the knee AP placement) are needed.

You'll find an extensive discussion of these topics at:


and the data from my students' experiments are on the CGA normative data
page at:

The US mirror at http://aisr1.lib.tju.edu/cga may be quicker for you.

Best wishes,

Dr. Chris Kirtley MD PhD
Dept. of Rehabilitation Sciences
The Hong Kong Polytechnic University
Hong Kong
Special Administrative Region of The People's Republic of China

Tel: +852 2766 6755 (lab 4830) Fax: 2764 1435
Home: http://www.polyu.edu.hk/~rs/kirt/index.htm
PolyU Gait Lab: http://www.rs.polyu.edu.hk/gaitlab

Clinical Gait Analysis: http://www.polyu.edu.hk/cga
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