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John C. Laughlin
10-15-1997, 05:09 AM
Thanks to all who replied to my original query. I recieved many useful
replies.

Original Post:

Does anyone know of any biomechanical or gait analysis research
involving tripping while walking. I am interested to know average trip
distances or steps taken with respect to walking speed before falling
and also the influence of sex or weight (especially obesity). I would
also like to know if there is any research done on the causation of
trips with unknown causes (i.e. tripping for no apparent reason).

Thanks,

John


Here is a summary of the responses (there were many so this post is
quite long!):


John,

Check with Mark Grabiner at the Cleveland Clinic.
grabiner@bme.ri.ccf.org

Bob Gregor


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


Dear John,

I have looked at tripping from a motor control perspective (eg,
intersegmental forces, reflexes). I applied a tripping perturbation to
normal subjects as they walked. However, although subjects exhibited a
tripping response, they did not fall, that is, they recovered from the
perturbation successfully. The following two papers will give you some
ideas of the mechanics and reflexes that are involved:

Eng, J.J., Winter, D.A. & Patla, A.E. (1997). Intralimb dynamics
simplify
reactive control strategies during walking. Journal of Biomechanics, 30,
581-588.

Eng, J.J., Winter, D.A. & Patla, A.E. (1994). Strategies for recovery
from
a trip in early and late swing during human walking. Experimental Brain
Research, 102, 339-439.

Hope that is helpful,

Janice Eng

__________________________________________________ __________________
Janice Eng, PhD, PT
Assistant Professor
School of Rehabilitation Sciences
Faculty of Medicine
University of British Columbia
T325 - 2211 Wesbrook Mall
Vancouver, British Columbia, Canada
V6T 2B5
Tel: (604) 822-7571
Fax: (604) 822-7624
E-Mail: JENG@REHAB.UBC.CA

************************************************
I have managed to find something on "stumbling" some time ago at
http://www.medizin.fu-berlin.de/biomechanik/Reship1e.htm#topic
but there are some changes to the site since. Try to search for it.

I am also interested in any other info on tripping forces etc. I would
appreciate it if you could refer me to more info if you have any.
Thanks.

***********************************************
John,

There is an ongoing study at the VA in Palo Alto concerning balance.
They
have done a lot of controlled tripping studies.

Good luck,
Mark Richter

************************************************** *
John,

I would be interested in what you get back on this subject. I do have
one reference for you
though:-

Hip Joint Loading During Walking & Running, Measured in two Patients.

Bergmann et al.

J. Biomechanics Vol 26. No 8. pp 969 - 990. 1993

During the work done for this paper they recorded the patients stumbling
and make reference to
this as the hip forces become extremely large.

Hope to hear from you,

Simon L. Smith

Univercity of Durham, England.
S.L.Smith1@durham.ac.uk

************************************************** **************
John:

> Does anyone know of any biomechanical or gait analysis research
> involving tripping while walking.
At University of Michigan, our Biomechanics Research Laboratory has been
devoted on trip and fall research for several years. This lab is
directed
by Dr. Albert Schultz and Dr. James Ashton-Miller.
Related publications could be found in our web page:
http://www.engin.umich.edu/dept/meam/brl/

>I am interested to know average trip
> distances or steps taken with respect to walking speed before falling
> and also the influence of sex or weight (especially obesity).
Is your term "trip distance" defined as the distance from trip
initiation
to when the trip is recovered or finished (people lay on ground)?

>I would also like to know if there is any research done on the causation of
> trips with unknown causes (i.e. tripping for no apparent reason).
Do you mean a trip that is caused without an obstacle or a trip
happened that people don't remember what caused?

Cheng Cao, PhD
Research Fellow
Department of Mechanical Engineering and Applied Mechanics
The University of Michigan, ANN ARBOR
(810) 997 4565

************************************************** **
Mr. Laughlin:

We have been carrying out research dealing with slips/falls. Our major
efforts have been in the area of the effects of envrionmental, job-task
and personal risk factors in modifying the potential of slips/near falls
and falls in industrial workers. Some of our publications are listed in
our lab's Home Page.

If you need to discuss these further please feel free to contact me.

--
------------------------------------------------------
Amit Bhattacharya, Ph. D., CPE; Biomechanics Ergonomics
bhattaat@uc.edu Research Laboratories
Ph: (513) 558-0503 Dept of Environ Health
Fax: (513) 558-2263 University of Cincinnati
Cincinnati, OH
45267-0056

(http://www.uc.edu/~bhattaat/welcome.html)
------------------------------------------------------
************************************************** ************
John:

I am currnetly involved in a study of tripping while walking in healthy
young adults and will shortly be looking at patients who have had a
reconstructed anterior cruciate ligament. To induce tripping I have
developed a treadmill that reverses direction extremely rapidly and then
returns to the original speed and direction (all within about .2
second).
thus far we have videotaped 8 individuals, but the analysis has not
gotten very far.

V, Dietz and colleagues did a similar study using a similar method in
the 1980's. He published three reports, much of them containing the
same data. In the reports, there was little attention paid to the
kinematics, rather, the EMG was emphasized. That's why I think it is
worth repeating. And also because I want to compare the data with the
patients. I am also considering study elderly individuals who tend to
fall for no apparent reason. By the patients, our subjects wear a
safety harness while tripping. Thus far, all but one have been able to
successfully recover from the trips. The tripping itself is induced
at randomly selected hell-strikes.

The Dietz references are:

Gollhofer et al. Compensatory movements....Int. J. Sports Med.
7:325-9,1986.
Berger et al. Corrective reactions to ......J. Physiol. 357:100-25,
1984.
Dietz et al. Corrective reactions to Neuroscience Letters 44:131-5,
1984.

Let me know if you need more information. I could probably send you a
tape of one of the subjects if you want to see it.

Joel A. Vilensky, Ph.D.
Indiana University School of Medicine
2101 Coliseum Blvd., E.
Fort Wayne, IN 46805

(219) 481-6738
************************************************** *************
Hey John:

Here is the abstract to three articles I found with Medline. I hope
this helps.


1
UI - 97229003
AU - Chou LS
AU - Draganich LF
IN - Department of Surgery, University of Chicago, Illinois, USA.
TI - Stepping over an obstacle increases the motions and moments of the
joints of the trailing limb in young adults.
SO - Journal of Biomechanics 1997 Apr;30(4):331-7
AB - Tripping over obstacles is the most frequently mentioned causes of
falls. Thus, this study was performed to test the hypotheses that
when crossing obstacles, toe-obstacle clearance and the
three-dimensional motions and moments at the hip, knee, and ankle
of
the trailing limb (limb crossing the obstacle last) increase with
obstacle height. Data were collected using an optoelectronic
digitizing system and force platform. Fourteen healthy young
adults
were tested during unobstructed level walking and when stepping
over
obstacles of 51, 102, 153, or 204 mm heights. Toe-obstacle
clearances of the trailing foot increased from 31 mm during
unobstructed gait to an average of 146 mm when stepping over
obstacles of any of these heights. Obstacle height was not found
to
affect toe-obstacle clearance. When the toe of the trailing limb
was
over the obstacle, the flexion angles of the hip and knee
increased
linerly with obstacle height. Compared to flexion of the hip or
ankle, flexion of the knee appears to be of primary importance
when
crossing obstacles with the trailing limb. The maximum extension
moment at the hip joint during late stance decreased linearly with
obstacle height. At the knee joint, the maximum flexion moment
during early stance and the maximum adduction moment during late
stance increased linearly with obstacle height. At the ankle
joint,
the maximum dorsiflexion moment during late stance increased
linearly with obstacle height. These greater demands on motions
and
moments may affect the abilities of those elderly having decreased
muscle strengths to step over obstacles.

2
UI - 96218891
AU - Chen HC
AU - Schultz AB
AU - Ashton-Miller JA
AU - Giordani B
AU - Alexander NB
AU - Guire KE
IN - Department of Mechanical Engineering and Applied Mechanics, Ann
Arbor Veterans Administration Medical Center, USA.
TI - Stepping over obstacles: dividing attention impairs performance of
old more than young adults.
SO - ddistik Mitteilungen&Chelsea Hotel: a Magazine for the
Arts Heinrich
Mann-Jahrbuch1Kintop: Jahrbuch zur E 1996 May;51(3):M116-22
AB - BACKGROUND. Tripping over an obstacle is a common cause of falls
in
the elderly. An earlier study of abilities to avoid stepping on
suddenly appearing obstacles found that, although healthy old
adults
had a lower rate-of-success than young adults, the magnitude of
that
difference was not large. The present study inquired whether
dividing attention during such a task would differentially affect
young and old healthy adults. METHODS. Rates-of-success were
observed in 16 young and 16 old healthy adults (mean ages 24 and
72
years) in avoiding stepping on a band of light that was suddenly
projected across their gait path while they walked at their
comfortable gait speed. This virtual obstacle was placed at
predicted next-footfall locations to give 350 or 450 msec
available
response times before footfall. During most of the trials the
subjects were asked, in addition to trying not to step on the
obstacle, simultaneously to respond vocally as quickly as possible
when red lights near the end of the walkway turned on. These
attention-dividing reaction time tests were of two types:
synchronized, when only red lights lit at intervals synchronized
with the appearance of the obstacle, and unsynchronized, when
green
or yellow lights lit in addition to the red lights, with lighting
intervals not synchronized with the appearance of the obstacle.
RESULTS. When synchronized and unsynchronized reaction time tests
were conducted concurrently with the obstacle avoidance tasks,
mean
rates-of-success in avoidance decreased significantly in both
young
and old adults. With available response times of 350 msec, mean
success rates decreased from their no-division values in the young
adults by 14.7% for synchronized reaction and by 19.9% for
unsynchronized reaction, attention-dividing tests. Corresponding
mean decreases for the old adults were 32.0 and 35.7%. This age
difference in the effects of dividing attention was significant.
CONCLUSION. Both young and old adults had a significantly
increased
risk of obstacle contact while negotiating obstacles when their
attention was divided, but dividing attention degraded obstacle
avoidance abilities of the old significantly more than it did in
the
young. Diminished abilities to respond to physical hazards present
in the environment when attention is directed elsewhere may
partially account for high rates of falls among the elderly.

3
UI - 95206722
AU - Spaulding SJ
AU - Patla AE
AU - Elliott DB
AU - Flanagan J
AU - Rietdyk S
AU - Brown S
IN - Faculty of Applied Health Sciences, Elborn College, London,
Ontario,
Canada.
TI - Waterloo Vision and Mobility Study: gait adaptations to altered
surfaces in individuals with age-related maculopathy.
SO - Optometry & Vision Science 1994 Dec;71(12):770-7
AB - Walking is an extremely complex task that can become seriously
challenged if one of the sensory systems which provides input to
the
motor system is compromised. The present study evaluated gait
adaptations to altered surface characteristics and high and low
ambient light conditions by subjects with age-related maculopathy
(ARM). Twenty subjects with ARM and 20 control subjects walked
along
a 6 m path, along which they met 1 of 3 altered surfaces
(compliant,
uneven, or shiny). Kinematic data and ground reaction forces
information were analyzed to discern gait adaptation strategies
used
by the ARM group. Ten trials on each surface were collected under
both high and low ambient light levels. The ARM subjects were
found
to be generally more cautious when walking on the altered
surfaces.
For example, they walked more slowly, with a longer swing time.
However, gait adaptations in the ARM group were not merely scaled
versions of normal gait but were adjustments to adapt to
environmental changes. Gait was modified to avoid tripping over a
surface edge, to prevent slipping at heel contact, and to balance
during stance. These adaptations enabled subjects to maintain safe
mobility when walking in a challenging environment.



Fabian
************************************************** ****************
This doesn't directly address your question, but here is my summary
for a similar question. There may be some references which are
beneficial.

I would appreciate a summry of the responses you receive.

Please note, my email address will be changing to, effective monday
October 13, 1997:

tfisch100@aol.com


______________________________ Forward Header
__________________________________
Subject: summary: Body motion when falling.
Author: TERRY FISCHER at SRC-ML
Date: 9/3/97 11:42 AM


On July 29, 1997 I posted the following:
__________________________________________________ _________________
__
I've been asked to look at a case in which an individual reported
that
he fell down a flight of stairs. When found, he was laying face
down
a relatively long distance from the base of the stairs.

I have been searching for reference material on the motion of
individuals when falling but have come up dry. The closest
references
I have found address the prevention of slip and fall injuries.

I would appreciate any references which would aid in my assessment.

__________________________________________________ _________________
__
I wish to thank everyone that responded. Below are copies of the
responses I receive.


Responses
__________________________________________________ _________________
__

I worked at the National Rehabilitation Hospital in Washington,
DC where the rehabilitation engineering department attempted a
study
on falling in association with long leg braces. The contact person
is
Tom Dang. I do not know the number off hand, but the address is
102
Irving Street, Washington, DC 20010. He might be able to help.

__________________________________________________ _________________
___

Try looking for papers written by Richard G. Snyder in the 60's and
70's. He and Clyde C. Snow investigated a number of freefall
accidents from bridges and other structures in the early days of
trying to understand impact trauma in the transportation industry.
Drs Snyder and Snow worked at the Civil Aeromedical Institute
(CAMI),
FAA in Oklahoma City and Dr. Snyder left to be part of the Highway
Safety Research Insitute (HSRI), The University of Michigan, now
called the University of Michgan Transportation Research Institute
(UMTRI). The papers are probably published in a journal such as
Aviation Medicine or as SAE technical papers or similar sources.
You
might find a case study based upon similar circumstances in one of
their publications.

__________________________________________________ _________________
___

You are right in that there have been few publications on
trajectories
of people falling on stairs, largely because of difficulty of
specifying initial conditions. I would look for recent citations
of
the following (or contact John Archea directly):

Archea, J.C.,
``Environmental factors associated with stair accidents by the
elderly'',
Clinics in Geriatric Medicine, 1(3): 555-570, 1985.
__________________________________________________ _________________
___

Certain falls (e.g., falls from standing height) have been well
described in the literature. After that, things get pretty chaotic
(in
the mathematical sense!)

You might be better off looking at the injury pattern and trying to
relate that back to the alleged accident scenario. This may involve
a
biomechanical analysis. We have cosiderable experience in this area
if
you need help.

John.

--
John Trimble, Ph.D.
jtrim@interaccess.com
Packer Engineering, Inc.
+1.630.505.5722
__________________________________________________ _________________
___

I don't know anything about this field, but I remember having seen
one
abstract about this topic in the European Society of Biomechanics
congress in Rome, 1992. I've been looking up the reference for you
in
the proceedings of this conference :
Y.E. Toshev,"Fall of the human body : criminological aspect.",
Proceedings of the Eight meeting of the ESB, Rome, Italy, 1992, p
378.
The authors' address at the time of the meeting was : Toshev Yuri
Inst.
of Mechanics and Biomechanics
Bulgarian Academy of Sciences
Acad. G. Bontchev Str. Block 4
1113 Sofia, Bulgaria
__________________________________________________ _________________
___

By searching the following two authors you could found many
valuable
information:

1. Albert B. Schultz
2. Mark Grabiner

Good luck.
__________________________________________________ _________________
___

We have been conducting for some years laboratory based
occupational
biomech/ergo research studies where we simulate slips and near fall
(we do not let subjects fall by using a harness) under various
lighting conds, floor conditions and task demands. During these
testings we measure body segment motions with multi-camera system
for
quantitating (by calcualting a series of biomechanical indices
defined
with respect to subject's base of support) potential loss of
balance.

I am not sure whether you are interested in the above info;
nevertheless you can get our list of relevant publications by
visiting
our Home Page listed below. (In particular, you may find the
following
reference of some interest to you: Wang B., Bhattacharya, A.,
Bagchee, A., and Wang, W., "Kinematic Methods for quantitating loss
of
balance while negotiating a curved path on a slippery surface" J.
Of
Testing and Evaluation Vol. 25, No.1, January 1997, pp 135-142.)

While we haven't had the opportunity to study the body motion
associated with loss of balance during stair climbing, our
Fall/Stability Lab is certainly equipped to address this issue as a
potential future project.


Hope this is of some help to you. If you need to contact me please
feel free to reach me.

Best regards

--
------------------------------------------------------ Amit
Bhattacharya, Ph.D, CPE Biomechanics Ergonomics bhattaat@uc.edu

Research Laboratories Ph: (513) 558-0503

Dept of Environ Health Fax: (513) 558-2263 University
of
Cincinnati
Cincinnati, OH 45267-0056

(http://www.uc.edu/~bhattaat/welcome.html)
------------------------------------------------------

************************************************** ***********
Hey John,

Saw your post on Biomech-L. At the ASB meeting in Clemson, there were
several of presentations related to trips/falls/postural
sway/age/obstacle clearance, etc. I can give you the authors' abstract
titles here, maybe they have more complete results in the literature.

1. Postural Sway and Limits of Stability are not Predictors of Fall
Recovery in Healthy Older Adults. TM Owings, MJ Pavol, KT Foley, MD
Grabiner. Cleveland Clinic Foundation, Cleveland, OH.

2. A Kinematic Analysis of Obstacle Clearance Strategies in Normal
Gait. T Thomas, M Tillman. Univ. of Forida, Gainsville

3. Model for Producing Tripping of the Trailing Foot on an Obstacle.
LF Draginach, L Chou. Univ. of Chicago.

4. The Effect of Toe-Obstacle Distance on Toe-Obstacle Clearing of the
Trailing Foot. L Chou, LF Draganich. Mayo Clinic.

Cheers,

Ranman

************************************************** ******************
Hi John

I read your massage on the biomch-l. Trips and falls for with unknown
causes - there have been some papers published from some researchers
here in New Zealand about falls in the elderly where a combination of
factors can be the cause of the fall.

Try searching the medical literature under Professor A. John Campbell,
or Dr Robyn Norton, the Physiotherapist involved is Melinda Gardner. I
don't know how much gait analysis has been done by this group but I know
they have been investigating causation.

Regards
Yvonne Bird



Yvonne Bird
HRC Training Fellow
Injury Prevention Research Unit
University of Otago, PO BOX 913
DUNEDIN, NEW ZEALAND

Ph: (03) 479 8526
Fax: (03) 479 8337
************************************************** ***************
John,

I recently finished a graduate assistantship in the biomechanics lab of
the Cleveland Clinic where there was an extensive trip and fall research
effort that used approximately 80 elderly subjects. You might contact
Mike Pavol, a PhD student who was very involved in the study
(pavol@bme.ri.ccf.org) or Dr. Mark Grabiner, who was the PI
(grabiner@bme.ri.ccf.org). Good luck.

Rachel Beyer

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




John C. Laughlin M.Eng.
Rimkus Consulting Group, Inc.
Eight Greenway Plaza, Suite 500
Houston, Texas 77046

Voice: (713) 621-3550
Fax: (713) 623-4357
Email: jcl@rimkus.com
biomech@rimkus.com

HTTP://www.rimkus.com