Hello, palatkagirl-ga!
Transfer of momentum in reference to the study of Kinesiology
commonly refers to energy transfer between individual body segments in
order to execute an efficient movement - with one segment decelerating
while the next one accelerates. Transfer of momentum is of great
interest to athletes, since proper form can greatly affect the speed
and power with which a movement is executed.
It is difficult to find references to online links that provide a
good picture of momentum transfer. Obviously, the most useful
explanations will be found in kinesiology and biomechanics textbooks,
which are only available offline (and which I assume you have access
to.) Many of the references I have provided are from articles or
lectures, so you will be limited to the online citations (for example
- chapter xx of a professor's lecture).
However, along with any offline textbooks you might have at hand, the
following references should serve to illustrate various ways transfer
of momentum is used in the study of Kinesiology.
==
The following example comes courtesy of one of my old Kinesiology
books, titled "Kinesiology - Scientific Basis of Human Motion. 7th
Edition." Kathryn Luttgens and Katherine F. Wells. Sanders College
Publishing. 1982. (There is no online link to this text - rather, it
is sitting in my lap at the moment!!)
From Chapter 16 - "Moving One's Body on the Ground or Other Resistant Surfaces."
"Principle V - "The momentum of any part of a supported body can be
transferred to the rest of the body. For instance, if one sits on the
end of a table with the legs hanging down, then lies down on the back
and raised the legs overhead until the feet almost touch the table
behind the head, and then vigourously swings both limbs
forward-downward, suddenly checking their motion when they touch the
table, the trunk will rise to a vertical position. Or, if one stands
with one arm extended forward and then flings it horizontally
sideward-backward as far as possible, the whole body will tend to
follow the arm in horizontal rotation."
==
EXAMPLES OF TRANSFER OF MOMENTUM AND APPLICATIONS TO HUMAN MOVEMENT
PITCHING AND HITTING
=====================
The following is a rather simple explanation of the way momentum
transfer works throughout the body segments to form an efficient
energy chain in the action of throwing a baseball.
From the Sports Engineering and Training Products Website
http://www.setpro.com/NEWWEB/mmax02.htm
"Kinetic chain is the key to explaining how the body develops power to
throw and hit. Many of you have heard and know that power starts with
the feet. But how does power actually work its way from the feet to
the hands. The science to explain this is called the "kinetic chain".
*** Dynamic transfer of momentum (think of momentum in terms of how
much force it takes to start and stop and object) from one body part
to the next is what the kinetic chain is all about. Just think of it
as our dominos example, momentum goes from feet to legs to hips to
torso to shoulder to arms to hands to ball or bat. "Dynamic" rotation
of the hips (shoulders not yet rotating) is responsible for setting up
the transfer of momentum to the upper body (shoulders)."
=
Another explanation of the transfer of momentum in the baseball pitch
can be found in the following lecture on Linear Kinetics from Troy
State University: (This is Chapter Twelve of the Professor's lecture -
not from a book)
http://spectrum.troyst.edu/~esmith/352lectlinearkinetics.htm
"Summation of Forces - Forces generated in one segment of the body can
be summed. These forces are used to build momentum, which is then
transferred from segment to segment. Example: In throwing, the force
generated by the legs pressing against the ground, generates momentum
which is transferred to the trunk, where further muscular force
application generates more momentum that is then transferred to the
upper arm. Due to the lower mass of the arm, the transfer of momentum
from the trunk results in a increase in the velocity of the upper
arm. When contraction of muscles in the upper arm to create more
impulse, a further increase in velocity occurs until the momentum is
finally transferred to the thrown ball."
SOCCER INSTEP KICK
===================
From "KINEMATIC INSTEP KICKING DIFFERENCES BETWEEN ELITE FEMALE AND
MALE SOCCER PLAYERS," by William Roy Barfield, Donald T. Kirkendall,
and Bing Yu. Journal of Sports Science and Medicine. (2002) 1, 72-79
http://www20.uludag.edu.tr/~hakan/sbtd/n3/4/n3-4text.php
(From the Introduction)
"In the sport of soccer, instep kicking (IK) is one of the most
fundamental and frequently used skills. In mature, skillful, soccer
athletes the instep kick involves a complex interaction of angled
approach to the ball, subsequent support foot contact (SFC) with the
ground
* accompanied by sequential transfer of momentum from proximal to
distal body segments in the swing or kicking limb.
Following the angled approach the support foot is placed alongside and
adjacent the ball with the toe of the support foot pointed in the
intended direction of ball movement. The kicking limb at SFC is in a
position of hip extension, knee flexion and ankle plantar flexion. In
powerful IK, following preparation of the kicking limb, the hip is
forcefully flexed and the knee is sequentially extended so that forces
generated can be channeled into propelling the ball. At ball/foot
contact powerful kickers keep the foot/ankle complex locked and
tightly plantarflexed so forces for propelling the ball can be
maximized."
DROP PUNT KICK IN FOOTBALL
==========================
From "Muscle Activity During the Drop Punt Kick," by John Orchard,
Sharon Walt, Andrew McIntosh and David Garlick. Journal of Sports
Science. 1999, 17(10):837-838 (Abstract)
http://injuryupdate.com.au/images/research/muscleactivitydroppunt.pdf
Discussion:
"Previous naming conventions for the various phases of kicking have
been confusing as certain phases were named with respect to what the
kicking leg is doing whereas others are referring to the stance leg.
Our phase names refer only to the kicking leg. We prefer the terms
backswing, wind-up and forward swing when describing the swing phase
of kicking before ball contact,
* as they correctly describe the proximal to distal segment transfer of momentum.
During the backswing both the thigh and leg are moving backwards (i.e.
hip extending and knee flexing). The wind-up is when the thigh is
moving forwards (hip flexing) but the knee is still flexing, so the
leg lags behind the thigh. The forward swing is when both thigh and
leg are moving forwards. The momentum built up during the wind-up is
transferred to the leg, which rapidly accelerates during the forward
swing.
* Alexander and Holt (1974) concluded that more efficient transfer of
momentum from the foot to the ball occurred when contact was made with
the ankle region rather than the metatarsals.
Plangenhoef (1971) reported a case of a punter who lost distance when
wearing a shoe which prevented full plantar flexion at the ankle,
suggesting that this was also important with respect to efficient
transfer of force. Our subjects kept their ankle joints relatively
fixed in plantar flexion during kicking which is consistent with these
previous findings."
TRANSFER OF MOMENTUM FROM SITTING TO STANDING
==============================================
From Baybutt, Stephen M., MS Neural Mechanisms Underlying Human
Movement. EMS 634: Dr. Marjorie Woollacott. 1(1,2): 1-50. Dec. 1998.
http://www.baybutt.net/pubs/neuralmech.html
2. Transfer
"The transfer phase begins as the buttocks leave the seat, and
involves transfer of momentum of the upper body to the whole body to
facilitate lifting the body. Both horizontal and vertical motion is
present in this phase, which is dependent upon the stabilization of
the body's center of mass over the base of support of the feet.14 The
primary force being overcome in this movement is gravity, and in some
sense, the transfer phase can be thought of as a series of movements
defined as a reflex model of motor control against the pull of
gravity. As the upper body flexes forward, the COM lies outside of the
body over the new, or future, base of support of the feet. Horizontal
momentum is converted to vertical momentum at this point, as various
anti-gravity muscles (gastrocnemius, rectus femoris, vastus medialis,
biceps femoris, and gluteus maximus) begin to contract to counter the
forward [horizontal] momentum of the COM."
=
The following article also provides a picture of how physical
impairment can inhibit momentum transfer when rising from a chair:
Also read "Lifting characteristics of functionally limited elders," by
Michael S. Puniello, MS, PT, OCS; Chris A. McGibbon, PhD; David E.
Krebs, PhD, PT. Journal of Rehabilitation Research and Development.
Vol. 37 No. 3, May/June 2000. Pages 341 - 352
http://www.vard.org/jour/00/37/3/punie.htm
"When rising from a chair, subjects with strength, balance, or
functional impairments must use a strategy that controls momentum
while maintaining balance and stability (25-30). Schenkman et al. (25)
concluded that two possible strategies could be used to compensate for
lower limb impairment: 1) position the upper body over the COM in a
more favorable position over the feet or 2) use the upper body forward
momentum to transfer into vertical momentum during the initial phase
of arising, controlled by coordinated leg movement. Dynamic stability,
or maintaining postural stability while the body is moving, is
important for a momentum transfer strategy to be successful (25).
Elderly subjects with moderate impairment used a momentum transfer
strategy while maintaining stability (25). Weaker subjects have less
capability to control for greater momentum and keep the base of
support close to the COM for optimal stability (28). No study to date
reports correlating sit-to-stand with lifting, therefore, we do not
know if weaker subjects would use a momentum transfer strategy during
lifting, as they do during chair rise.
USING ARM SWING TO TRANSFER MOMENTUM DURING A VERTICAL JUMP
============================================================
(If the link below does not work for html version, simply type the
title into your search engine. The word document has no link, in and
of itself)
From "The Mechanics of the Vertical Jump," by William W. Colvin.
Exercise Physiology Laboratory. California State University, Chico (no
date)
http://216.239.57.104/search?q=cache:1htdysPtZtcJ:www.sportsci.org/encyc/drafts/Vertical_jump.doc+the+mechanics+of+the+vertical+jump&hl=en
Transfer Of Momentum Of The Arm-Swing:
"The contribution of the arm-swing during counter movement VJ
(vertical jump) has been estimated at 10%. This was reported by Komi
and Bosco using a force plate and recording the ground resistance
forces (GRF) of jumpers with and without arm swing. The use of the
arm-swing during a maximum VJ is extremely complicated and requires
precise timing."
"The transfer of momentum from the arm swing is best demonstrated by
attaching a weight (10% of body weight) of 18 lbs. to a 3 ft. rope.
Throw the weight vertically with a final velocity of 10 ft/sec. When
the weight reaches the end of the rope, .11 sec later, it will create
a force upwards of 51 ft-lbs/sec. (m= 18/32.2, a= 10/.11) The rope
represents the role of an eccentric muscular contraction, transferring
force from the arms to the trunk. The timing of the transfer of the
angular momentum from the arms to the trunk through an eccentric
contraction of the L.D., T.M., P.M must occur during the steep wall of
the GRF. The force from the arm-swing and from the trunk and head
extension, serve the purpose of unloading those parts of the body
(reducing the mass), since they are already in vertical motion."
TRANSFER OF ANGULAR MOMENTUM IN THE STEMME FOWARD IN GYMNASTICS
=================================================================
Please read through entire article:
"The Stemme Forward: Biomechanical Relationships," by William L.
Cornelius, Ph.D. University of North Texas, Denton, Texas
http://www.usa-gymnastics.org/publications/technique/1996/8/stem-forward.html
"There is a relationship between anatomical and mechanical aspects of
human motion. An example of this relationship can be shown in the
stemme forward (Figure 1) and the connection between anatomical
components of the human body and transferring angular momentum. For
the gymnasts to effectively transfer angular momentum from one body
segment to another there must be a sequence of functional muscle group
contractions."
====
I hope these references, in conjunction with other kinesiology
materials you might already have on hand, will help you to better
understand the principle of transfer of momentum and how it is applied
to movements of the human body.
Sincerely,
umiat
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Clarification of Answer by
umiat-ga
on
29 Nov 2004 21:01 PST
Hello again, palatkagirl!
According to some further research, it appears that the 7th edition
was printed in New York City.
Saunders College Publishing has it's primary office in Philadelphia.
However, on the inside cover of my book, under Saunders College
Publishing, there is not just one city listed, but several. The cities
listed - in order - are Philadelphia, New York, Chicago, San
Francisco, Montreal, Toronto, London, Sydney, Tokyo, Mexico City, Rio
de Janeiro and Madrid. There is also a simple statement that the book
was printed in the United States.
As there are several editions of this particular volume, I checked
online to see if I could find a copy with the same ISBN - 0030583586.
Abe's Books does have several copies of the 7th volume, which is the
book I cited. (See listing numbers 1,2,4,8,21,22,26,27,29
http://www.abetitles1.com/Title/1560726/Kinesiology+Scientific+Basis+of+Human+Motion.html
** Out of all the listings with this ISBN #, the only one which
specifies the city of print is listing #2, which specifies New York.
Therefore, I would go with New York!
http://dogbert.abebooks.com/servlet/BookDetailsPL?bi=367006856
In case you are interested, the front cover of the book is shown in at
the following link: http://dogbert.abebooks.com/servlet/BookDetailsPL?ph=2&bi=303193018
The page numbers for the excerpt I cited were 444-445.
I hope this helps!
umiat
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