PDA

View Full Version : Summary of Joint Stiffness



Justin Ludcke
08-20-2000, 04:27 PM
Biomch-L,

Following my original question is a summary of replies. I am in the process
of investigating these avenues. Thank you to all those who replied.

Original Question:
> Biomch-L Colleagues,
>
> I have a query that relates very closely to a question recently posed by
> John Finan (University College Dublin) on joint stiffness. Within our
> research we are modelling the Standing Hybrid III Dummy on a moving floor.
> The defined joint stiffness of the lower limbs (particularly the knee)
> consist of little or no stiffness throughout the normal range of motion
> with a dramatic increase when nearing the end of the joint ROM. This is to
> simulate the physical end-limits of joint motion.Therefore any upward
> movement of the floor causes the dummy to crumble. Is there any data or has
> there been any work done on the stiffness properties of these joints in
> anticipation of an upward force? For example, the stiffness in the knee
> before landing from a jump. We are not primarily concerned with any
> increased stiffness due to increased muscle activation during the impact.
> We would like some idea of joint stiffness applied by the semi-conscious
> muscle activation in anticipation of the upward force.
>
> Your help would be greatly appreciated and a summary will be posted.
>
> Thanks,
> Justin

RESPONSE 1:
Dear Justin,

In my opinion, (I would say just to be polite) joint stiffness is not a
parameter which the nervous susystem cares about while controls any
movement. You can take a look at the article: Feldman AG, Ostry DJ, Levin
MF, Gribble PL, and Mitnitski AB. Recent tests of the equilibrium-point
hypothesis (lambda model). Motor control 2: 189-205, 1998 for very clear
explanations. You can also take a look at the papers of D. Ostry and P.
Gribble in Biocybern appeared about at the same time. There are the
examples of simulation of poiting movement. As far as I know, there is no
publications of the simulation of knee joint approach using the same
approach (started by Dr Feldman 30 years ago), though I myself performed
some preliminary simulations but nothing has been published... .

There is no anticipation of the reaction force (again, in my opinion),
using the techniques corresponding to the lambda-model, one don't need any
anticipation. Everything will be the concequence of the control parameters
specified before the movement (for fast movements).

If you have any questions about the matter I will be happy to discuss them,
Arnold

Arnold B. Mitnitski
Ecole Polytechnique, Applied Mechanics Dept.

RESPONSE 2:
Any increase in joint stiffness in mid-range can come only from muscle
activation either in anticipation of an upward force or in response to an
unexpected force. When landing from a jump subjects anticipate landing and
usually activate muscles before or shortly after contact with the ground,
thereby stiffening the knee and other lower limb joints. However, the
stiffness properties are complex as there is high short-range stiffness to
small changes in knee and lower stiffness after the short-range is
exceeded. This is a complex issue. Good luck with it.

Sincerely,
Warren Darling

RESPONSE 3:
Justin,

You should have done some searching on your own (or let us know that you
did). Nevertheless, here are some references:

PASSIVE JOINT STIFFNESS:
Mansour, JM and Audu, ML (1987) Passive Elastic Moment at the Knee and its
Influence on Human Gait. Journal of Biomechanics 19: 51-58.
Yoon, YS and Mansour, JM (1982) Passive Elastic Moment at the Hip. Journal
of Biomechanics 15: 905-910.
Weiss, PL, Kearney, RE and Hunter, IW (1986) Position Dependence of ankle
joint dynamics -- I. passive mechanics. Journal of Biomechanics 19: 727-735.

OVERALL LEG STIFFNESS:
Farley, CT, Glasheen, J and McMahon, TA (1993) Running springs: Speed and
animal size. Journal of Experimental Biology 185: 71-86.
Farley, CT and Gonzalez, O (1996) leg stiffness and stride frequency in
human running. Journal of Biomechanics 29: 181-186.
Ferris, DP and Farley, CT (1997) Interaction of leg stiffness and surfaces
stiffness during human hopping. Journal of Applied Physiology 82: 15-22;
discussion 13-4.
Ferris, DP, Louie, M and Farley, CT (1998) Running in the real world:
adjusting leg stiffness for different surfaces. Proceedings of the Royal
Society of London - Series B: Biological Sciences 265: 989-94.
McMahon, TA and Cheng, GC (1990) The mechanics of Running: How does
stiffness couple with speed. Journal of Biomechanics 23: 65-78.
McMahon, TA and Greene, PR (1979) The influence of track compliance on
running. Journal of Biomechanics 12: 893-904.
McMahon, TA, Valiant, G and Frederick, EC (1987) Groucho running. Journal
of Applied Physiology 62: 2326-2337.

LANDING (AND CATCHING):
Armand, M, Huissoon, JP and Patla, AE (1998) Stepping over obstacles during
locomotion: insights from multiobjective optimization on set of input
parameters. IEEE Transactions on Rehabilitation Engineering 6: 43-52.
Dyhre-Poulsen, P, Simonsen, E and Voight, M (1991) Dynamic control of
muscle stiffness and H reflex modulation during hopping and jumping in man.
Journal of Physiology 437: 287-304.
Gross, TS and Nelson, RC (1988) The shock attenuation role of the ankle
during landing from a vertical jump. Medicine and Science in Sports and
Exercise 20: 506-514.
Lacquaniti, F, Carrozzo, M and Borghese, NA (1993) Time-varying mechanical
behavior of multijointed arm in man. Journal of Neurophysiology 69: 1443-1464.
Lee, DN and Young, DS (1986) Gearing action ot the environment.
Experimental Brain Research Series 15: 217-230.
McKinley, P, and Smith, JL (1983) Visual and vestibular contributions to
prelanding EMG during jump downs in cats. Experimental Brain Research 52:
439-448.
McKinley, P, , Smith, JL and Gregor, RJ (1983) Responses of elbow extensors
to landing forces during jump downs in cats. Experimental Brain Research
49: 218-228.
McKinley, P and Pedotti, A (1992) Motor strategies in landing from a jump:
The role of skill in task execution. Experimental Brain Research 90: 427-440.
McNitt-Gray, JL (1993) Kinetics of the lower extremities during drop
landings from three heights. Journal of Biomechanics 26: 1037-1046.
Melvill Jones, G and Watt, DGD (1971) Muscular control of landing from a
unexpected falls in man. Journal of Physiology 219: 729-737.
Wicke, RW and Oman, CM (1982) Visual and graviceptive influences on lower
leg EMG activity in humans during brief falls. Experimental Brain Research
46: 324-330.

J A M E S P A T T O N , P H . D .
Research Associate,
Sensory Motor Performance Program
Rehabilitation Institute of Chicago.

RESPONSE 4:
Justin,
Sounds like pretty challenging and interesting work. I have modelled (in
Pro/Mechanica) a shoulder and elbow joint in the past and just used a
different figure for static and dynamic friction coefficients. I don't
think that helps you much though. I have a few suggestions;
1. Add MADYMO muscles around the joints (they don't have to be exact) then
look in the Automotive impact literature (SAE STAPP Conferences,
International Research Council On the Biomechanics of Impact proceedings -
IRCOBI, Enhanced Safety of Vehicles Conference - ESV) for data on lower
limb muscle activity in pre-impact braking and add this to your model.
2. Look at the knee joint stiffness (Cardan Restraints are used) in the
Madymo EEVC Legform Impactor and then add these (or similar magnitude -
check result sensitivity) constraints to your model.
3. Talk to MADYMO help (they really are very helpful!) about how they would
recommend solving the problem.

Hope this helps
Mike.

Michael Buckley
Senior Safety Engineer
Daewoo Worthing Technical Centre

RESPONSE 5
Justin,

We published:

DeVita, P. & Skelly, W. (1992). Effect of landing stiffness on joint
kinetics and energetics in the lower extremity. Medicine and Science in
Sports and Exercise, 24, 108-115.

and one section emphasized the anticipatory adjustments made during the 100
ms prior to contact. We did not assess actual stiffness however but had
subjects land with relatively soft (much flexion) and stiff (little
flexion) techniques.

Paul DeVita


----------------------------------------------------------------------------
----------------
Justin Ludcke
PhD Student
School of Mechanical, Manufacturing and Medical Engineering
Queensland University of Technology
GPO Box 2434
Brisbane Q 4001
AUSTRALIA

Ph: +61 7 3864 2980
Fax: +61 7 3864 1469
Email : j.ludcke@qut.edu.au
----------------------------------------------------------------------------
----------------

---------------------------------------------------------------
To unsubscribe send SIGNOFF BIOMCH-L to LISTSERV@nic.surfnet.nl
For information and archives: http://isb.ri.ccf.org/biomch-l
---------------------------------------------------------------