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Richard Evans, Sphe (utoronto)
11-17-1994, 01:03 AM
Hello Biomch-L'ers!

Many thanks to all of those who responded to my "knee wrapping"
questions. I didn't know so many Biomechanists were former
weightlifters. I received many interesting "personal experience"
responses. This seems to be an area requiring further investigation as
the literature on the biomechanics knee wrapping is sparse. The
responses and my original posting follow:


Date sent: Fri, 11 Nov 1994 11:22:44 -0500
Send reply to: EVANS@PHE.UTORONTO.CA
From: "Richard Evans, SPHE (UToronto)"

Organization: UofT Physical & Health Education
Subject: Knee wrapping for weightlifting
To: Multiple recipients of list BIOMCH-L

Greetings BIOMCH-L'ers!

I have a student who wants to look at the function of
wrapping the knees when performing heavy weightlifting activities. He
has been unable to locate any significant research in this area.
Initially, I would suspect that the effects are predominantly
psychological and not mechanical. Perhaps the wrapping warms the
knee joint which may serve to cause fluid inflow to the tissues?!
Do tight wraps increase the potential for injury? Is there any
research on this topic out there? I will be glad to post a
summary of the responses. Thanks.

Richard Evans
Biomechanics Lab
School of Physical and Health Education
University of Toronto
Canada

e-mail: evans@phe.utoronto.ca
__________________________________________________ ____________________
RESPONSES:

Recently a doctorate thesis on this subject was published in the
Netherlands. The effects of cold and heat on (rheumatic)joint
temperature (intra- articularly measured) was evaluated.>
I don't know exactly where and when and certainly haven't read it. If
you think you are interested I can make an attempt to find out
further details and send them to you.

With kind regards,

Gert Jan Kleinrensink
Research Group Musculo Skeletal System
Dept. of Anatomy
Erasmus University Rotterdam
The Netherlands
__________________________________________________ ____________________

Although I do not have any experience with weightlifting (horses
seldomly perform this kind of exercise), I can support your statement
on mechanical influence of wrapping joints from a completely different
perspective. In horse race industry quite some trainers and breeders
have the lower limbs of the horses bandaged before racing. There is
one obvious advantage: damage due to collisions, or touching one limb
with the other will be avoided. However, some claim that the bandaging
is also effective in preventing eccesive overextension of the lower
limb joints. We did some accurate in vitro experiments, and we were
not able to detect a positive effect comparable with the joint
moments, normally occurring in vivo. Obviously, there was a minimal
support, but that approached the detection level of our rather
accurate measuring equipment. If you want to obtain more detailed
information, I can supply you with a description of the measurement
procedures, and some of the results. In conclusion: bandaging in
horses is hardly or not effective in supporting joints. Translated to
human athletes: do not expect too much positive influence in
mechanical terms; wrapping might be effective from a psychological
point of view though.

All the best,

Henk
Henk C. Schamhardt
Department of Anatomy, Faculty of Veterinary Medicine
Utrecht University, P.O. Box 80.157, NL-3508 TD Utrecht
The Netherlands
phone: int+31-30-534325/534336 FAX: int+31-30-516853
Email: h.c.schamhardt@POBox.ruu.nl
__________________________________________________ ____________________

I don't know of any real publications about wrapping knees but I'm
sure there are articles written Muscle and Fitness or other various
powerlifting/bodybuilding mags. I don't wrap my knees and never have.
I figure that if the ligaments, tendons, other structures get the
load apappropriately. My lifting buddies who lift more weight(>400lbs)
use wraps because they feel it adds stablity to the knee. There is a
weights mail list that I could post a note to for you to see if anyone
has any real research to point to and not just opinion. I have read
that the fellow who has the heaviest squat(~1000lbs) that he does not
wrap except for lifts of greater than 800lbs.

Dave

Dave Giurintano
Paul Brand Biomechanics Lab
GWL Hansen's Disease Center
Carville LA 70721 giurin@resdjg.gwlhdc.lsu.edu
__________________________________________________ ____________________

You are right. To my knowledge, there is no literature dealing with
this subject. As an experienced powerlifter, however, I would suggest
two possible effects of the knee wraps. One would be a passive knee
extensor moment provided by the tightly wrapped, tough, elastic wrap.
Second, (more often found in Olympic Weightlifting) a knee wrap placed
below the patella provides relief from the infrapatellar tendonitis
pain (or perhaps even prevents it). I was told by one physiotherapist,
that such a wrap changes slightly the direction of the tendon force
vector, enough to relieve the pain stemming from inflamed tendon
fibres near the insertions to the bone.

Sincerely, Jacek Cholewicki
Biomechanics Research Laboratory
Department of Orthopaedics
Yale University School of Medicine
__________________________________________________ ____________________

I am aware of one article that has look at the effect of knee wraps
on weightlifting. It appears that it will aid in performance. The
reference is as follows:

Harman E, & Frykman, P. (1990). The effects of knee wraps on
weightlifting performance and injury. National Strength and
Conditioning Association Journal, vol 12, #5, pp 30-35.

Hope this helps

************************************************** ********************
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* Danny Too, Ph.D. Phone: (702)-895-4875 *
* University of Nevada Las Vegas Fax: (702)-895-4231 *
* 4505 Maryland Parkway E-mail: dtoo@nevada.edu *
* Las Vegas, NV 89154-3034 *
* *
************************************************** ********************
__________________________________________________ ____________________

I have no research to back this up, but here is my personal experience
with wrapping the knees and heavy lifting: The main effect _is_
mechanical; if you wrap the knees very tightly, the wraps serve as a
sort of "spring"around the knee joint, assisting in extending the
joint. For example, imagine wrapping your knees very tightly while
the leg is straight. After doing this, it is very difficult to bend
the knees. So, when squatting, for example, the knee wrap assists in
increasing the angle between the leg and thigh. As far a causing an
inflow of fluid to the tissues, I don't think so. As a matter of
fact, if you wrap the knees tightly (as you should) the blood flow to
the feet is decreased. The wraps are usually kept on for only about a
minute- not nearly long enough to significantly increase tissue
temperature.
--
William Anderst
__________________________________________________ ____________________

This is interesting because I have had experience with knee wraps and
weight lifting. I am not sure how much is psychological, but I know
that I could definitely lift the weight more easily with them than
without them.

Perhaps it has to do with stability and/or constraint-issues. By
tightly wrapping the knee, it seems you are essentially adding a
"stronger" connective element at that joint. This may reduce motions
in other directions and effectively constrain the knee to bend or move
along only one axis. For instance, think of trying to push a heavy
weight that is balanced on a long pole up the side of a wall. Compare
this with the effort required if the weight was attached to a unirail
that only allowed the weight to move vertically; i.e., constrained to
one axis of movement. The second case should be much easier because
the motion is constrained. This is just a guess, but it seems to make
sense to me. I am curious to see what other responses might be.

good luck,

Young Hui

================================================== ====================

607-253-3551 Young Hui Chang
yhc3@cornell.edu Department of Anatomy
College of Veterinary Medicine
Ithaca, NY 14853-6401

================================================== ====================
__________________________________________________ ____________________

Have your student contact Dr. Mary Verstraete
Motion Analysis Laboratory
Department of Biomedical Eng.
University of Akron
Akron, OHIO 44325-0302
(216) 972-7691

Dr. Verstraete has had several student looking into this area for some
time. Regards.

================================================== ================
DANIEL B. SHEFFER, PH.D., HEAD BITNET R1DBS@AKRONVM
DEPARTMENT OF BIOMEDICAL ENG. INTERNET R1DBS@VM1.CC.UAKRON.EDU
UNIVERSITY OF AKRON TELEPHONE 216 972 6650
AKRON, OHIO 44325-0302 TELEFAX 216 374 8834
================================================== ================
__________________________________________________ ____________________

The information that i have and my personal experience supports
the idea that knee wraps provide more than a psychological effect.
the mechanical effect of the wrap itself, if done properly, is an
additional elastic benefit that may add 25 pounds or so to a given
power squat performance. one reference to begin with may be
Essentials of Strength Training and Conditioning (edited by Baechle
published by Human Kinetics), which is a new text and a good resource
for those preparing for NSCA certification. the text states that
using knee wraps may actually cause some types of injuries (such as
chondromalacia patellae) and therefore their use should be limited to
near maximal lifts.

One reference within the text to use as a start may be:
Harman, E. and P. Frykman. The effects of knee wraps on weightlifting
performance and injury. NSCA Journal 14(1): 47-54. 1992.

this is an area in need of more investigation,
thanks,
michael
_______________________________________________
michael bird, ph.d.
texas tech university
tobir@ttacs.ttu.edu
phone:+1 (806) 742-3371
fax: +1 (806) 742-1688
_______________________________________________
__________________________________________________ ____________________

In one of my previous incarnations I competed in powerlifting and so
will give you the anecdotal impressions of a biomechanist that has
used the damn things.

The tighter the wraps are applied the better they work. Stiffness of
the material is a big factor lifters consider in wrap selection. There
seems to be an effect of 'wrap rebound' in assisting in the extension
of the knee when coming out of a deep squat (when forces on the wraps
have reached unbelievably high levels). I think this may be the major
effect. Also I think there is some danger of knee damage when such
high forces on the knee are being experienced and the wraps probably
play a key role in injury prevention here, stabilizing the joint and
preventing excess ligament strain, though I believe that is a
secondary consideration to most competitors. That may also have a
psychological effect in that lifters are more willing to attempt
higher loads while feeling more secure about their knees with wraps on
them. There may also be an effect of constraining outwards flow of
joint fluid and with the high pressure of the wrap surrounding the
knee it may act to maintain lubrication between joint surfaces even
when they are subject to abnormally high loads. Another aspect that
I'll speculate on is the mechanical effect of securing and
constraining the tendons in the knee area, which may somehow
affect the force-production characteristics of those muscles. Lastly,
the application of the wraps is the final important act in the
competition pre-lift 'psyching up' ritual and the pain that very tight
wraps cause for those last few seconds prior to a big lift may play a
role to some individuals in getting the mental focus they need for
that maximal effort.

In personally advising lifters, unless the individual had knee
injuries, I'd tell them to make minimal use of wraps (and belts, bench
press shirts, squat suits, etc., too, for that matter) during
training, so that the concentration is on building
muscle/tendon/ligament strength and not relying on external factors,
and then bringing wraps/belts into use in the final weeks
of competition preparation to gain that extra 'edge'.

Regards,
N

Nancy R. Deuel, PhD nd26@umail.umd.edu
*-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**
* University of Maryland Equine Sports Biomechanics Laboratory *
* 1113 Animal Sciences Center Animal Sciences Department *
* University of Maryland Phone: 301/405-1385 *
* College Park, Maryland 20742 USA Fax: 301/314-9059 *
*-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**
__________________________________________________ ____________________

As a past Junior Olympic weightlifter, I have some first hand
knowledge of this practice. I never wrapped my knees, but I knew many
lifters, especially older ones, that did this. Usually they would
wrap their knees very tightly right before they were going to lift and
then take off the wraps immediately after finishing. In this case, I
could not see how the wraps would have time to effect the temperature
of the muscles, limaments, and other soft tissues in time to help
with the lift. The reasons that the lifters quoted to me when they
used the lifts was that it "stabilized" or "stiffened" the knee.
Whether it actually did this or if it was purely psychological as you
suggest it might be, I'm not sure. If it was actually stiffening the
knee, you could measure this with either a force platform and video
analysis or with some sort of force transducer and
electrogoiniometer. I would suggest your student look into the topic
of "joint stiffness" in his literature search. There is quite a
large number of studies in this area, especially for the knee.
By examining the joint stiffness unwrapped unloaded, wrapped
unloaded, unwrapped loaded, and wrapped loaded, your student could
determine if the wrapping is increasing the stiffness of the knee.
This might be benficial because it might provide a slower descent
with better control during the eccentric phase. If you have a
computerized medline search, try the key words joint and stiffness,
and muscle and stiffness. If you can't find anything, let me know
and I will try to dig up some of the relevant citations.

Best of luck,

Dan Ferris
Department of Human Biodynamics
103 Harmon
University of California at Berkeley
Berkeley, CA 94720
dferris@uclink2.berkeley.edu
__________________________________________________ ____________________
----------------------------------------------------------------------

Richard Evans
Biomechanics Laboratory
School of Physical and Health Education
University of Toronto
Canada

e-mail: evans@phe.utoronto.ca