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Dear Biomech-L readers,
thanks a lot to all who responded to my questions on arm swing during
human walking. The replies are listed below.
Stefan Gruber
--
Dipl.-Ing. Stefan Gruber
Institute B of Mechanics
University of Stuttgart
Pfaffenwaldring 9
D-70550 Stuttgart phone: ++49 711-685 7659
Germany fax: ++49 711-685 6400
mailto:sg@mechb.uni-stuttgart.de
http://www.uni-stuttgart.de/mechb/people/Gruber
================================================== ====================================
As the arm swing is a natural action - exaggerated only in marching
actions, I believe that its action would be to maintain the body's
centre of gravity above the point of contact and thus minimise the
muscular effort required to balance the body. It would be the same
effect in running - running with no arm swing would be decidedly
uncomfortable.
While I can't say that I have any references, perhaps a camera
positioned above the treadmill will show the relative positions of arms
and bodies when the subject is walking.
Alastair Campbell Ritchie
IMRE
S7 level 3
National University of Singapore
Singapore 119260
================================================== ===============================
Dear Stefan,
you may want to take a look at the publications by Robert Wagenaar and
Richard van Emmerich during the last eight years or so. They have
analysed human walking both in different types of patients and controls
using a dynamical systems approach. Publications give clues on the
experimental set-up, but also theoretical background of using arm swing
during human walking. It is interesting to note, by the way, that there
are two different swinging modes, dependent on walking speed. It is also
well known, that counterrotation of the upper trunk is necessary to keep
balance; obviously, swinging arms amplify this balancing motion pattern.
Hope this helps. regards,
Theo Smit
University Hospital Vrije Universiteit
================================================== ===========================
Although I do not know the answers to your questions, I know someone who
probably does:
Dr. David Webb
Dept. of Anthropology and Sociology
Kutztown University
Kutztown, PA 19530 USA
email: webb@kutztown.edu
Dr. Webb did his originial doctoral research on arm swinging in human
locomotion. So, if he can't answer your questions, he probably knows how
to find them.
--
Thomas M. Greiner, Ph.D.
Assistant Professor
Department of Anatomy
New York Chiropractic College
Seneca Falls, NY 13148-0800 USA
Phone Office: (315) 568-3183
Phone Lab: (315) 568-3239
Fax: (315) 568-3017
EMail: tgreiner@nycc.edu
================================================== ==========================
Stefan:
My Ph.D. (1989) was on the function of the upper limbs in human walking,
so I have some familiarity with the literature of that time. I
published
my main project as:
Webb, David, Russell H. Tuttle and Michael Baksh, "Pendular Activity of
Human
Upper Limbs During Slow and Normal Walking," American Journal of
Physical
Anthropology, Vol.93, pp.477-89, 1994.
1. There are several references in that article which indicate that
arm-swinging is partly active, rather than fully passive. This is
especially true of retraction (extension) at the shoulder, which
requires
the use of the posterior deltoid muscle. I strongly recommend finding
all
the references cited in my paper, and there may be several more by now.
(In fact, I do not recall the Hinrichs paper you mentioned in your
e-mail,
and I would appreciate your giving me the full bibliographic information
so I can look it up. I have the following article from Hinrichs:
Hinrichs, Richard N., "Regression Equations to Predict Segmental Moments
of Inertia from Anthropometric Measurements: an Extension of the Data of
Chandler, et al.", Journal of Bone and Joint Surgery, Vol.18, No.8,
pp.621-4, 1985. || moments of inertia about transverse & longitudinal
axes)
2. Elftman (among others) was convinced that the major function of
arm-swinging in human walking was indeed to balance rotational forces in
the human trunk, and I recommend his article to you: Elftman, Herbert,
"The Function of the Arms in Walking", Human Biology, Vol.11, pp.529-35,
1939. Also, by reducing the rotation of the trunk, reaction forces
between the feet and the ground should also be reduced, at a given
speed,
since the body would be moving in a more efficient manner.
With regard to your treadmill setup, it would be nice to have a
treadmill
from which ground reaction forces (GRF's) could be measured, but I don't
know where to get one, and it may be too late for you, anyway. Others
have used force plates to measure GRF's in various directions, and this
information would be useful to you. You might try to find the following
article: Herman, R., R. Wirta, S. Bampton and F.R. Finley, "Human
Solutions for Locomotion: I. Single Limb Analysis", in Herman,
Grillner,
Stein and Stuart, eds., Neural Control of Locomotion, Advances in
Behavioral Biology, Vol.18, Plenum Press, New York, 1976, pp.13-49. ||
lots of good basic info on v, stride len & freq, jt. angles, grnd reac
F's, stance/swing, some EMG. Unfortunately, I don't recall anyone
measuring rotational GRF's, only linear ones.
My experience with treadmills has been quite good, overall. I suspect
that your results will be perfectly usable, but I have a couple of
cautions: (1) the treadmill may maintain a more constant speed during
a
stride than a human normally would (i.e., humans slow down as we "vault"
over the supporting limb, and the treadmill may prevent that); (2) if
you are using standard video, you will be able to sample at 30 frames
per
second, which might be a little slow for some of the details of
movement,
tending to smooth your kinematic data and obscure some fast
accelerations
which a force plate would catch.
Finally, I have read some articles about 3-D kinematic models of human
walking, but most of them were more complex (mathematically) than I was
able to use. You might try these: Jackson, K.M., J. Joseph and S.J.
Wyard,"A mathematical model of arm swing during human locomotion",
Journal
of Biomechanics, Vol.11, pp.277-89, 1978. || EMG's of brach.,
brach/rad.,
tric., bic., delt., lat.dors., pec. maj.; surface electrodes only;
model
incl.'s mus. torque, elastic torque, friction, link len., CoM (a la
Dempster) & accel/ton due to trunk mv/ment; Mochon, Simon and Tomas A.
McMahon, "Ballistic walking: An improved model," Mathematical
Biosciences, Vol.52, pp.241-60, 1980. || passive model of swing phase is
fairly close to clinical data, o( , ) swing phase is virtually passive;
Bryant, J.T., H.W. Wevers and Philip J. Lowe, "One parameter model for
error in instantaneous centre of rotation measurements", Journal of
Biomechanics, Vol.17, No.5, pp.317-23, 1984. || gives a table and a
graph
to correct experimental values for position of 'instantaneous center of
rotation', determined by X-rays or following pins in bones.
I hope this information is helpful to you. Good luck with your
research,
and please let me know when and where you publish your work. I'm very
interested.
Sincerely,
David Webb
================================================== ======================
The Hinrichs paper I mentioned is:
Richard N. Hinrichs: Whole Body Movement: Coordination of Arms and Legs
in Walking and Running. Multiple Muscle Systems - Biomechanics and
Movement Organization, Jack M. Winters and Savio L-Y. Woo (editors),
Springer-Verlag, 1990, chapter 45, p.694-705.
some other interesting ones are:
Richard N. Hinrichs and Peter R. Cavanagh and Keith R. Williams: Upper
Extremity Function in Running. I: Center of Mass and Propulsion
Considerations. International Journal of Sport Biomechanics, vol 3,
1987, p.222-241.
Richard N. Hinrichs, Upper Extremity Function in Running. II: Angular
Momentum Considerations, International Journal of Sport Biomechanics,
vol 3, 1987, p.242-263.
Stefan Gruber
================================================== ======================
Stefan,
Try these sources in regard to arm swing:
Ballesteros, M.L.F., Buchthal, F., & Rosenfalck, P. (1965) The pattern
of
muscular activity during the arm swing of natural walking. Acta
Physiol.
Scand., 63, 296-310.
Cappozzo, A., Figura, F., Leo, T., Marchetti, M. (1978) Movements and
mechanical energy changes in the upper part of the human body during
walking. In E. Asmussen & K. Jorgensen (Eds.), Biomechanics VI-A (pp.
272-279). Baltimore: University Park Press.
Duchenne, G.B. (1959) Physiology of motion (E.B. Kaplan, Translator).
Philadelphia: W.B. Saunders.
Elftman H. (1939) The function of the arms in walking. Human Biology,
11,
529-535
Figura, F., Marchetti, M., & Leo, T. (1985) Kinematics of the female
upper
body during ambulation at various speeds. In D.A. Winter (Ed.)
Biomechanics
IX-A (pp. 457-461). Champaign, IL: Human Kinetics.
Hogue, R. E. (1969) Upper-extremity muscular activity at different
cadences
and inclines during normal gait. Physical Therapy, 49, 963-972.
Murray, M.P. (1967, 1970, 1984) There are 4 studies or articles
published
by Murray and colleagues. The sources are as follows: American Journal
of
Physical Medicine, Archives of Physical Medicine and Rehabilitation,
Physical Therapy, and Journal of Orthop. Res.
Hope these help. I took these references from my dissertation "A
three-dimensional analysis of shoulder and pelvic kinematics during
walking".
Marilyn Miller
University of Wisconsin - La Crosse
134 Mitchell Hall
La Crosse, WI 54601
================================================== =========================
Dear Stefan,
I think you should search papers about speed skating.
The skater use the arm swing to accelerate
on short distances (500 m) and skate without arm swing
to save energy on long distances (10 000 m).
I hope it helps
Christian
************************************************** ******
* Dr.Christian Peham
* email: Christian.Peham@vu-wien.ac.at
* Clinic for Orthopaedics in Ungulates
* Locomotion Research Group
* University of Veterinary Medicine Vienna
* Phone: +43-1-250 77/5506; Fax: +43-1-250 77/5590
* Josef Baumanngasse 1; A-1210 Wien
* http://www.vu-wien.ac.at/i111
************************************************** ******
================================================== ====================
Mr. Gruber,
What an interesting question !
Indeed, there is only very little literature available on that area. I
am very interested in that topic also. I am working on a bipedal walking
robot. I am using a ballistic principle (does McGeer/ McMahon ring a
bell ?). One of my goals is to stabilize an upper body in a limit cycle
on the pelvis while walking. The compensating motions of the upper body
with respect to the walking stability are very interesting matter. I am
not yet that far, but I will also start on extending my model with torso
motions soon.
Meanwhile there are two fields to get some information:
1. data from measurements from the biomechanical field:
Winter D.A., Ruder G.K., MacKinnon C.D., 'Control of balance of
upper body during gait'. in: Multiple Muscle Systems: Biomechanics and
movement organisation (ed. Winters J.M., Woo, S.L-Y,). 1990
Springer-Verlag. pp: 534-541.
2. control theories from the robotic field.
Work which involves ZMP-theories
I my opinion there has not yet been published a noteworthy paper for the
problem you are trying to answer. So keep on researching, we'll keep in
touch !
Richard
Ir. R.Q. van der Linde
Delft University of Technology
Faculty of Design, Engineering and Production
Laboratory of measurement and Control
Mekelweg 2
2628CD DELFT, The Netherlands
tel.nr: +31-152786585
fax: +31-152784717
Email: R.Q.vanderLinde@wbmt.tudelft.nl
================================================== ==========================
Hello Stefan,
You might want to look at the following papers:
Jackson, KM, Joseph, J and Wyard, SJ; A mathematical model of arm swing
during human locomotion. J Biomech. 1978; 11(6-7): 277-289.
Jackson, KM, Joseph, J and Wyard, SJ; The upper limbs during human
walking. Part I: Sagittal movement. Electromyogr Clin Neurophysiol. 1983
Sep; 23(6): 425-434.
Jackson, KM, Joseph, J and Wyard, SJ; The upper limbs during human
walking. Part 2: Function. Electromyogr Clin Neurophysiol. 1983 Sep;
23(6): 435-446.
I only have ther first paper handy, and can tell you that it's a 2-D
(sagittal plane) model of arm swing.
Hope this helps,
Pascale
================================================== ==========================
"Alterations in gait resulting from deliberate changes of arm-swing
amplitude and phase"
clinical biomechanics Vol 12,No 7/8,pp.516-521,1997.
Sincerely
B. Auvinet
================================================== =============================
Dr. Gruber,
For references regarding your inquiries about arm swing in gait, see our
paper in Clinical Kinesiology:
Sigg, JA, JC Ives, BC Gaba, and GA Sforzo. Effect of arm position on
parameters
of normal gait in older persons. Clinical Kinesiology. 51:33-36, 1997.
We tried to make the references as complete as possible concerning
theories
of how and why the arms swing as they do.
Regards,
Jeff Ives, PhD
Dept. Exercise and Sport Sciences
Ithaca College
Ithaca, NY 14850 USA
jives@ithaca.edu
================================================== =============================
-------------------------------------------------------------------
To unsubscribe send UNSUBSCRIBE BIOMCH-L to LISTSERV@nic.surfnet.nl
For information and archives: http://www.bme.ccf.org/isb/biomch-l
-------------------------------------------------------------------
thanks a lot to all who responded to my questions on arm swing during
human walking. The replies are listed below.
Stefan Gruber
--
Dipl.-Ing. Stefan Gruber
Institute B of Mechanics
University of Stuttgart
Pfaffenwaldring 9
D-70550 Stuttgart phone: ++49 711-685 7659
Germany fax: ++49 711-685 6400
mailto:sg@mechb.uni-stuttgart.de
http://www.uni-stuttgart.de/mechb/people/Gruber
================================================== ====================================
As the arm swing is a natural action - exaggerated only in marching
actions, I believe that its action would be to maintain the body's
centre of gravity above the point of contact and thus minimise the
muscular effort required to balance the body. It would be the same
effect in running - running with no arm swing would be decidedly
uncomfortable.
While I can't say that I have any references, perhaps a camera
positioned above the treadmill will show the relative positions of arms
and bodies when the subject is walking.
Alastair Campbell Ritchie
IMRE
S7 level 3
National University of Singapore
Singapore 119260
================================================== ===============================
Dear Stefan,
you may want to take a look at the publications by Robert Wagenaar and
Richard van Emmerich during the last eight years or so. They have
analysed human walking both in different types of patients and controls
using a dynamical systems approach. Publications give clues on the
experimental set-up, but also theoretical background of using arm swing
during human walking. It is interesting to note, by the way, that there
are two different swinging modes, dependent on walking speed. It is also
well known, that counterrotation of the upper trunk is necessary to keep
balance; obviously, swinging arms amplify this balancing motion pattern.
Hope this helps. regards,
Theo Smit
University Hospital Vrije Universiteit
================================================== ===========================
Although I do not know the answers to your questions, I know someone who
probably does:
Dr. David Webb
Dept. of Anthropology and Sociology
Kutztown University
Kutztown, PA 19530 USA
email: webb@kutztown.edu
Dr. Webb did his originial doctoral research on arm swinging in human
locomotion. So, if he can't answer your questions, he probably knows how
to find them.
--
Thomas M. Greiner, Ph.D.
Assistant Professor
Department of Anatomy
New York Chiropractic College
Seneca Falls, NY 13148-0800 USA
Phone Office: (315) 568-3183
Phone Lab: (315) 568-3239
Fax: (315) 568-3017
EMail: tgreiner@nycc.edu
================================================== ==========================
Stefan:
My Ph.D. (1989) was on the function of the upper limbs in human walking,
so I have some familiarity with the literature of that time. I
published
my main project as:
Webb, David, Russell H. Tuttle and Michael Baksh, "Pendular Activity of
Human
Upper Limbs During Slow and Normal Walking," American Journal of
Physical
Anthropology, Vol.93, pp.477-89, 1994.
1. There are several references in that article which indicate that
arm-swinging is partly active, rather than fully passive. This is
especially true of retraction (extension) at the shoulder, which
requires
the use of the posterior deltoid muscle. I strongly recommend finding
all
the references cited in my paper, and there may be several more by now.
(In fact, I do not recall the Hinrichs paper you mentioned in your
e-mail,
and I would appreciate your giving me the full bibliographic information
so I can look it up. I have the following article from Hinrichs:
Hinrichs, Richard N., "Regression Equations to Predict Segmental Moments
of Inertia from Anthropometric Measurements: an Extension of the Data of
Chandler, et al.", Journal of Bone and Joint Surgery, Vol.18, No.8,
pp.621-4, 1985. || moments of inertia about transverse & longitudinal
axes)
2. Elftman (among others) was convinced that the major function of
arm-swinging in human walking was indeed to balance rotational forces in
the human trunk, and I recommend his article to you: Elftman, Herbert,
"The Function of the Arms in Walking", Human Biology, Vol.11, pp.529-35,
1939. Also, by reducing the rotation of the trunk, reaction forces
between the feet and the ground should also be reduced, at a given
speed,
since the body would be moving in a more efficient manner.
With regard to your treadmill setup, it would be nice to have a
treadmill
from which ground reaction forces (GRF's) could be measured, but I don't
know where to get one, and it may be too late for you, anyway. Others
have used force plates to measure GRF's in various directions, and this
information would be useful to you. You might try to find the following
article: Herman, R., R. Wirta, S. Bampton and F.R. Finley, "Human
Solutions for Locomotion: I. Single Limb Analysis", in Herman,
Grillner,
Stein and Stuart, eds., Neural Control of Locomotion, Advances in
Behavioral Biology, Vol.18, Plenum Press, New York, 1976, pp.13-49. ||
lots of good basic info on v, stride len & freq, jt. angles, grnd reac
F's, stance/swing, some EMG. Unfortunately, I don't recall anyone
measuring rotational GRF's, only linear ones.
My experience with treadmills has been quite good, overall. I suspect
that your results will be perfectly usable, but I have a couple of
cautions: (1) the treadmill may maintain a more constant speed during
a
stride than a human normally would (i.e., humans slow down as we "vault"
over the supporting limb, and the treadmill may prevent that); (2) if
you are using standard video, you will be able to sample at 30 frames
per
second, which might be a little slow for some of the details of
movement,
tending to smooth your kinematic data and obscure some fast
accelerations
which a force plate would catch.
Finally, I have read some articles about 3-D kinematic models of human
walking, but most of them were more complex (mathematically) than I was
able to use. You might try these: Jackson, K.M., J. Joseph and S.J.
Wyard,"A mathematical model of arm swing during human locomotion",
Journal
of Biomechanics, Vol.11, pp.277-89, 1978. || EMG's of brach.,
brach/rad.,
tric., bic., delt., lat.dors., pec. maj.; surface electrodes only;
model
incl.'s mus. torque, elastic torque, friction, link len., CoM (a la
Dempster) & accel/ton due to trunk mv/ment; Mochon, Simon and Tomas A.
McMahon, "Ballistic walking: An improved model," Mathematical
Biosciences, Vol.52, pp.241-60, 1980. || passive model of swing phase is
fairly close to clinical data, o( , ) swing phase is virtually passive;
Bryant, J.T., H.W. Wevers and Philip J. Lowe, "One parameter model for
error in instantaneous centre of rotation measurements", Journal of
Biomechanics, Vol.17, No.5, pp.317-23, 1984. || gives a table and a
graph
to correct experimental values for position of 'instantaneous center of
rotation', determined by X-rays or following pins in bones.
I hope this information is helpful to you. Good luck with your
research,
and please let me know when and where you publish your work. I'm very
interested.
Sincerely,
David Webb
================================================== ======================
The Hinrichs paper I mentioned is:
Richard N. Hinrichs: Whole Body Movement: Coordination of Arms and Legs
in Walking and Running. Multiple Muscle Systems - Biomechanics and
Movement Organization, Jack M. Winters and Savio L-Y. Woo (editors),
Springer-Verlag, 1990, chapter 45, p.694-705.
some other interesting ones are:
Richard N. Hinrichs and Peter R. Cavanagh and Keith R. Williams: Upper
Extremity Function in Running. I: Center of Mass and Propulsion
Considerations. International Journal of Sport Biomechanics, vol 3,
1987, p.222-241.
Richard N. Hinrichs, Upper Extremity Function in Running. II: Angular
Momentum Considerations, International Journal of Sport Biomechanics,
vol 3, 1987, p.242-263.
Stefan Gruber
================================================== ======================
Stefan,
Try these sources in regard to arm swing:
Ballesteros, M.L.F., Buchthal, F., & Rosenfalck, P. (1965) The pattern
of
muscular activity during the arm swing of natural walking. Acta
Physiol.
Scand., 63, 296-310.
Cappozzo, A., Figura, F., Leo, T., Marchetti, M. (1978) Movements and
mechanical energy changes in the upper part of the human body during
walking. In E. Asmussen & K. Jorgensen (Eds.), Biomechanics VI-A (pp.
272-279). Baltimore: University Park Press.
Duchenne, G.B. (1959) Physiology of motion (E.B. Kaplan, Translator).
Philadelphia: W.B. Saunders.
Elftman H. (1939) The function of the arms in walking. Human Biology,
11,
529-535
Figura, F., Marchetti, M., & Leo, T. (1985) Kinematics of the female
upper
body during ambulation at various speeds. In D.A. Winter (Ed.)
Biomechanics
IX-A (pp. 457-461). Champaign, IL: Human Kinetics.
Hogue, R. E. (1969) Upper-extremity muscular activity at different
cadences
and inclines during normal gait. Physical Therapy, 49, 963-972.
Murray, M.P. (1967, 1970, 1984) There are 4 studies or articles
published
by Murray and colleagues. The sources are as follows: American Journal
of
Physical Medicine, Archives of Physical Medicine and Rehabilitation,
Physical Therapy, and Journal of Orthop. Res.
Hope these help. I took these references from my dissertation "A
three-dimensional analysis of shoulder and pelvic kinematics during
walking".
Marilyn Miller
University of Wisconsin - La Crosse
134 Mitchell Hall
La Crosse, WI 54601
================================================== =========================
Dear Stefan,
I think you should search papers about speed skating.
The skater use the arm swing to accelerate
on short distances (500 m) and skate without arm swing
to save energy on long distances (10 000 m).
I hope it helps
Christian
************************************************** ******
* Dr.Christian Peham
* email: Christian.Peham@vu-wien.ac.at
* Clinic for Orthopaedics in Ungulates
* Locomotion Research Group
* University of Veterinary Medicine Vienna
* Phone: +43-1-250 77/5506; Fax: +43-1-250 77/5590
* Josef Baumanngasse 1; A-1210 Wien
* http://www.vu-wien.ac.at/i111
************************************************** ******
================================================== ====================
Mr. Gruber,
What an interesting question !
Indeed, there is only very little literature available on that area. I
am very interested in that topic also. I am working on a bipedal walking
robot. I am using a ballistic principle (does McGeer/ McMahon ring a
bell ?). One of my goals is to stabilize an upper body in a limit cycle
on the pelvis while walking. The compensating motions of the upper body
with respect to the walking stability are very interesting matter. I am
not yet that far, but I will also start on extending my model with torso
motions soon.
Meanwhile there are two fields to get some information:
1. data from measurements from the biomechanical field:
Winter D.A., Ruder G.K., MacKinnon C.D., 'Control of balance of
upper body during gait'. in: Multiple Muscle Systems: Biomechanics and
movement organisation (ed. Winters J.M., Woo, S.L-Y,). 1990
Springer-Verlag. pp: 534-541.
2. control theories from the robotic field.
Work which involves ZMP-theories
I my opinion there has not yet been published a noteworthy paper for the
problem you are trying to answer. So keep on researching, we'll keep in
touch !
Richard
Ir. R.Q. van der Linde
Delft University of Technology
Faculty of Design, Engineering and Production
Laboratory of measurement and Control
Mekelweg 2
2628CD DELFT, The Netherlands
tel.nr: +31-152786585
fax: +31-152784717
Email: R.Q.vanderLinde@wbmt.tudelft.nl
================================================== ==========================
Hello Stefan,
You might want to look at the following papers:
Jackson, KM, Joseph, J and Wyard, SJ; A mathematical model of arm swing
during human locomotion. J Biomech. 1978; 11(6-7): 277-289.
Jackson, KM, Joseph, J and Wyard, SJ; The upper limbs during human
walking. Part I: Sagittal movement. Electromyogr Clin Neurophysiol. 1983
Sep; 23(6): 425-434.
Jackson, KM, Joseph, J and Wyard, SJ; The upper limbs during human
walking. Part 2: Function. Electromyogr Clin Neurophysiol. 1983 Sep;
23(6): 435-446.
I only have ther first paper handy, and can tell you that it's a 2-D
(sagittal plane) model of arm swing.
Hope this helps,
Pascale
================================================== ==========================
"Alterations in gait resulting from deliberate changes of arm-swing
amplitude and phase"
clinical biomechanics Vol 12,No 7/8,pp.516-521,1997.
Sincerely
B. Auvinet
================================================== =============================
Dr. Gruber,
For references regarding your inquiries about arm swing in gait, see our
paper in Clinical Kinesiology:
Sigg, JA, JC Ives, BC Gaba, and GA Sforzo. Effect of arm position on
parameters
of normal gait in older persons. Clinical Kinesiology. 51:33-36, 1997.
We tried to make the references as complete as possible concerning
theories
of how and why the arms swing as they do.
Regards,
Jeff Ives, PhD
Dept. Exercise and Sport Sciences
Ithaca College
Ithaca, NY 14850 USA
jives@ithaca.edu
================================================== =============================
-------------------------------------------------------------------
To unsubscribe send UNSUBSCRIBE BIOMCH-L to LISTSERV@nic.surfnet.nl
For information and archives: http://www.bme.ccf.org/isb/biomch-l
-------------------------------------------------------------------