CGA FAQ, Marker attachment methods...

from BIOMCH-L March 2005

Dear all,
Here are the recommendations I received regarding appropriate clothing for
elderly women study.  I would like to thank everyone for their insights.

Hyun Gu Kang
From: Christopher Barr <>

One of the researchers in our lab uses a full body lycra suit on elderly
women, and this seems to be accepted by the vast majority of them.  It just
depends on how you "sell" the idea to them.  Some actually quite like it as
it can be quite flattering, making them look thinner.  Depending on how you
have your marker setup it is more accepted if they can wear a t-shirt over
the top half..  I also recall a talk by a local clinician who said that
using figure hugging lycra (she used cycling shorts) reduces error from
skin movement.

Also, we attach cluster markers with straps made out of wetsuit material
and a velcro backing - which appears to reduce errors due to skin movement,
although I am not sure if this has been quantified.
From: Randall Jensen <>

Your question addressed some interesting points and I shared it with my
colleague (Barb Coleman) who works with our senior fitness program. She
noted there may be modesty as well as physical issues and had a few
suggestions below:

1) Some subjects will be comfortable with the sports bra and bike shorts,
but might prefer keeping a tee shirt on until right before the test. If
they aren't out in "public", it may not be as much of an issue.

2) The sports bra issue might cause problems simply getting it on and off
due to limited flexibility of the arms and shoulders.

3) How about using a leotard? In some cases the name itself would be more
socially acceptable and dance clothing is something they have seen and
heard of for years.

4) Another alternative to bike shorts might be some sort of capri pants.
The longer aspect may again be more acceptable for modesty sake.
From: Katherine Whitcome <>

My research in part addresses posture and gait change in women during
pregnancy. In collecting 3D motion capture data I had my subjects wear
two-piece spandex attire. I needed access to landmarks along the vertebral
column as well as elsewhere on the body so I tried to minimize the presence
of fabric since it was likely to alter the position of the markers during
movement (good fit is important).  I bought very inexpensive jogging suits
(bra style and shorts) at Target and Walmart - I think each piece ran about
$6-$7.  The spandex was comfortable for the women and easily accommodated
changes in segment mass as the pregnancies advanced.

None of the women were opposed to wearing the "gait suit" - they were
fantastic about everything.  Before I had them formally consent to the
study I sat down with them and in my explanation of the expectations I
showed them photos of the lab - other subjects (with faces obscured) and
reconstructions from Vicon.  They had a chance then to see just what the
spandex suit looked like and in seeing other women it was easier for them
to visualize themselves dressed in the suit performing the tasks.

If you intend to work with healthy older women - you will hopefully find
that those willing to consider the study are confident and comfortable
enough to show more of their bodies than other women of that generation.
There is of course in your case a sex difference between researcher and
subjects that may be cause for more modesty on the part of the women if you
ask them to wear skimpy clothing. Since my subjects and I are women that
issue did not surface for me.

There is alot of "fashion" choice when it comes to work-out style clothing
now.  Your older women may feel more comfortable in the legging style pants
with a hem at the calf rather than the shorts that I used.  I don't think
you can beat the low price of the big box store work-out attire - so if it
works for you and your subjects, you'll save $$.
From: "Gutekunst, David J Mr USARIEM" <>

I don't have much advice on brand or material for full-body suits, since
in my experience testing older adults it seems unlikely that many
subjects will be interested in wearing a full-length lycra suit.  Of
course, that could have been due to the gender difference, as Ms.
Whitcome mentioned in a reply I just saw posted.  For clarification, my
master's work (at Wake Forest) was in a gait lab specializing in knee OA
in older adults; my current work with the Army doesn't really focus on
elderly women! :)

Given the wide variation in body size and dimensions among older adults
(extremely frail to morbidly obese) I wonder if it could become rather
costly to have suits to fit all body types.  Perhaps if your study
population is entirely non-obese then lycra body suits would be a more
appropriate option.  But you might consider the relatively simple and
low-cost option of purchasing athletic shorts which can be partially
rolled up for marker placement.  In many ways a loose style like
basketball shorts works best, since they are easiest to roll up.  Our
subjects seemed more willing to have their shorts partially rolled up
than to wear form-fitting lycra.

You didn't mention which marker system we'll be using.  In my work with
older adults we used the Helen Hayes marker set and therefore did not
have a greater trochanter marker, but if you are using a GT marker then
you might be pushing the limits of how far the shorts can be rolled
before the subject is self-conscious.

For the upper body, T-shirts or preferably the A-shirt style (more
commonly known by the politically incorrect term "wife beater") should
allow for marker placement.

A final bit of advice regarding self-consciousness of older adults,
whether you decide to go with lycra bodysuits or rolling up athletic
shorts: be sure to limit access to your lab space during testing so that
subjects don't have to worry about visitors or hordes of class-bound
students lumbering past.  And it may sound odd, but something as simple
as showing a stick figure reconstruction and explaining that the motion
capture cameras don't take actual "pictures" can help put your subjects'
minds at ease.
From: "Michael Orendurff" <>

     We have used underarmour clothing.  They are very tight, hold markers
well and aren't too hot. Try
From: Jennifer Baird <>

I have just completed my data collection for my master's thesis, which
included a group of women 65 years and older.  I also purchased spandex
shorts from wal-mart.  The shorts have a long inseam.  I had them wear a
t-shirt on top which was tucked into the shorts.  I collected full-body
kinematics, and this worked well.  They knew in advance they would wear
these clothes.  A few wore there own spandex leggings, which worked fine,
also.  In addition, I have curtains around the collection area so other
people coming into the lab can't see the subjects, which made them feel
more comfortable.
From: Denise Stilling <>

When doing elderly gentlemen with a posture/gait study related to
Parkinsonism --- we used a lycra -- cotton (black) above knee legging type
of short (not the satin spandex light reflecting biker short material) and
they fit really snug so that the material and markers didn't move when the
subject walked.  We used T-shirts for the top (again stretch cotton and a
size too small so it didn't move) but tank tops should be fine allowing for
bony landmarking.

I had an experiment where I had participants wear a sleeveless t-shirt
and asked that females wear their own clothing under it.  I specified
what I wanted fot their own clothing as soon as they responded to my
notice for participants - and allowed then to decline if they wished.
I also gave them a picture of a subject (who approved of me using the
picture) to show what people whould be wearing amd what I would affis
to joints. You might want to do things this way.

Older women would probably be more comfortable if their stomachs and
the top of their thighs are covered.  I do not think that they mind
having the rest of their legs uncovered.

I am not sure what body landmarks you are using for reflective
markers?  Do you need to put a marker on a body part that women would
prefer was covered?  If you do, can you cut a hole in an inexpensive
shirt or shorts (that you provide) and put a marker in the hole so that
the woman is covered?

AS far as room temperature goes,  I would think that young people are
more uncomfortable in a warm room than older people.

Hyun Gu Kang
Graduate student in Kinesiology - Movement Science
Nonlinear Biodynamics Laboratory
Bellmont Hall 530/540
University of Texas at Austin

1 University Station Stop D3700, BEL 222
Austin TX 78712

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