A simplified model of the mechanical properties of muscle and of the musculoskeletal geometry was used to predict torques at the shoulder and elbow during arm movements in the sagittal plane. Subjects made movements to 20 targets spaced on the diameter of a circle centered on the initial location of the hand. Movement kinematics and the electromyographic (EMG) activity of nine shoulder and elbow muscles were recorded. Muscle force was predicted using rectified EMG activity as an input to a Hill-type model of muscle dynamics. The model also made simplifying assumptions about muscle geometry. Muscle force was then converted to torque and the individual muscle torques were weighted to provide the best fit to the joint torque computed from the kinematic data. The overall fit of the model was reasonably good, but the goodness of fit was not uniform over all movement directions. The results suggest that the assumptions about the musculo-skeletal geometry, the model of muscle dynamics, and muscles not included in the analysis all contributed to the error.

1.
Angel
R. W.
,
1974
, “
Electromyography During Movement: The Two Burst Pattern
,”
EEG Clin. Neurophysiol.
, Vol.
36
, pp.
493
498
.
2.
Buchanan
T. S.
,
Almdale
D. P. J.
,
Lewis
J. L.
, and
Rymer
W. Z.
,
1986
, “
Characteristics of Synergic Relations During Isometric Contractions of Human Elbow Muscles
,”
J. Neurophysiol.
, Vol.
56
, pp.
1225
1241
.
3.
Buchanan
T. S.
,
Rovai
G. P.
, and
Rymer
W. Z.
,
1989
, “
Strategies for Muscle Activation During Isometric Torque Generation at the Human Elbow
,”
J. Neurophysiol.
, Vol.
62
, pp.
1201
1212
.
4.
Buneo
C. A.
,
Soechting
J. F.
, and
Flanders
M.
,
1994
, “
Muscle Activation Patterns for Reaching: the Representation of Distance and Time
,”
J. Neurophysiol.
, Vol.
71
, pp.
1546
1558
.
5.
Buneo
C. A.
,
Boline
J.
,
Soechting
J. F.
, and
Poppele
R. E.
,
1995
a, “
On the Form of the Internal Model for Reaching
,”
Exp. Brain Res.
, Vol.
104
, pp.
467
479
.
6.
Buneo
C. A.
,
Soechting
J. F.
, and
Flanders
M.
,
1995
b, “
Muscle Torque Directions at the Human Shoulder
,”
Soc. Neurosci. Abstr.
, Vol.
21
, Part 1, p.
423
423
.
7.
Dempster
W. T.
,
1965
, “
Mechanisms of Shoulder Movement
,”
Arch. Phys. Med. Rehab.
, Vol.
46
, pp.
49
70
.
8.
Evans, F. G., 1961, Biomechanical Studies of the Musculoskeletal System, CC Thomas, Springfield, IL, pp. 95–97.
9.
Flanders
M.
,
1991
, “
Temporal Patterns of Muscle Activation for Arm Movements in Three-Dimensional Space
,”
J. Neurosci.
, Vol.
11
, pp.
2680
2693
.
10.
Flanders
M.
, and
Herrmann
U.
,
1992
, “
Two Components of Muscle Activation: Scaling With the Speed of Arm Movement
,”
J. Neurophysiol.
, Vol.
67
, pp.
931
943
.
11.
Flanders
M.
,
Pellegrini
J. J.
, and
Soechting
J. F.
,
1994
, “
Spatial/Temporal Characteristics of a Motor Pattern for Reaching
,”
J. Neurophysiol.
, Vol.
71
, pp.
811
813
.
12.
Flanders
M.
,
Pellegrini
J. J.
, and
Geisler
S. D.
,
1996
, “
Basic Features of Phasic Activation for Reaching in Vertical Planes
,”
Exp. Brain Res.
, Vol.
110
, pp.
67
79
.
13.
Georgopoulos, A. P., Kalaska, J. F., Crutcher, M. D., Caminiti, R., and Massey, J. T., 1984, “The Representation of Movement Direction in the Motor Cortex: Single Cell and Population Studies,” in: Dynamical Aspects of Cortical Function, G. M. Edelman, W. E. Gall, W. M. Cowan, eds., Wiley, New York, pp. 453–473.
14.
Happee
R.
, and
Van der Helm
F. C. T.
,
1995
, “
The Control of Shoulder Muscles During Goal Directed Movements, an Inverse Dynamic Analysis
,”
J. Biomech.
, Vol.
28
, pp.
1179
1191
.
15.
Hogan
N.
, and
Flash
T.
,
1987
, “
Moving Gracefully: Quantitative Theories of Motor Coordination
,”
Trends Neurosci.
, Vol.
10
, pp.
170
174
.
16.
Ho¨gfors
C.
,
Sigholm
G.
, and
Herberts
P.
,
1987
, “
Biomechanical Model of the Human Shoulder. I. Elements
,”
J. Biomech.
, Vol.
20
, pp.
157
166
.
17.
Ho¨gfors
C.
,
Peterson
B.
,
Sigholm
G.
, and
Herberts
P.
,
1991
, “
Biomechanical Model of the Human Shoulder. II. The Shoulder Rhythm
,”
J. Biomech.
, Vol.
24
, pp.
699
709
.
18.
Hollerbach
J. M.
, and
Flash
T.
,
1982
, “
Dynamic Interactions Between Limb Segments During Planar Arm Movement
,”
Biol. Cybern.
, Vol.
44
, pp.
67
77
.
19.
Karst
G. M.
, and
Hasan
Z.
,
1991
, “
Timing and Magnitude of Electromyographic Activity for Two-Joint Arm Movements in Different Directions
,”
J. Neurophysiol.
, Vol.
66
, pp.
1594
1604
.
20.
Kaufman
K. R.
,
An
K.-N.
,
Litchy
W. J.
, and
Chao
E. Y. S.
,
1991
, “
Physiological Prediction for Muscle Forces I. Application to Isokinetic Exercise
,”
Neurosci.
, Vol.
40
, pp.
793
804
.
21.
Kearney
R. E.
, and
Hunter
I. W.
,
1990
, “
Systems Identification of Human Joint Dynamics
,”
Crit. Rev. Biomed. Engrg.
, Vol.
18
, pp.
55
87
.
22.
Messier
R. H.
,
Duffy
J.
,
Litchman
H. M.
,
Paslay
P. R.
,
Soechting
J. F.
, and
Stewart
P. A.
,
1971
, “
The Electromyogram as a Measure of Tension in the Human Biceps and Triceps Muscles
,”
Int. J. Mech. Sci.
, Vol.
13
, pp.
585
598
.
23.
Nashner
L. M.
, and
McCollum
G.
,
1985
, “
The Organization of Human Postural Movements: A Formal Basis and Experimental Synthesis
,”
Behav. Brain Sci.
, Vol.
8
, pp.
135
172
.
24.
Otis
J. C.
,
Jiang
C.-C.
,
Wickiewicz
T. L.
,
Peterson
M. G. E.
,
Warren
R. F.
, and
Santner
T. J.
,
1994
, “
Changes in the Moment Arms of the Rotator Cuff and Deltoid Muscles With Abduction and Rotation
,”
J. Bone Jt. Surg.
, Vol.
76A
, pp.
667
676
.
25.
Pedotti
A.
,
Krishnan
V. V.
, and
Stark
L.
,
1978
, “
Optimization of Muscle Force Sequencing in Human Locomotion
,”
Math. Biosci.
, Vol.
38
, pp.
57
76
.
26.
Press, W. H., Teukolsky, S. A., Vetterling, W. T., and Flannery, B. P., 1992, Numerical Recipes in C, Cambridge University Press, New York.
27.
Soechting
J. F.
, and
Lacquaniti
F.
,
1981
, “
Invariant Characteristics of a Pointing Movement in Man
,”
J. Neurosci.
, Vol.
1
, pp.
710
720
.
28.
Soechting
J. F.
,
Buneo
C. A.
,
Herrmann
U.
, and
Flanders
M.
,
1995
, “
Moving Effortlessly in Three Dimensions: Does Donders’ Law Apply to Arm Movement?
,”
J. Neurosci.
, Vol.
15
, pp.
6271
6280
.
29.
Uno
Y.
,
Kawato
M.
, and
Suzuki
R.
,
1989
, “
Formation and Control of Optimal Trajectory in Human Multijoint Arm Movement. Minimum Torque Change Model
,”
Biol. Cybern.
, Vol.
61
, pp.
89
102
.
30.
van der Helm
F. C. T.
,
1994
, “
Analysis of the Kinematic and Dynamic Behavior of the Shoulder Mechanism
,”
J. Biomech.
, Vol.
27
, pp.
527
550
.
31.
van der Helm
F. C. T.
, and
Pronk
G. M.
,
1995
, “
Three-Dimensional Recording and Description of Motions of the Shoulder Mechanism
,”
J. Biomech. Engrg.
, Vol.
117
, pp.
27
40
.
32.
Wadman
W. J.
,
Denier van der Gon
J. J.
, and
Derksen
R. J. A.
,
1980
, “
Muscle Activation Patterns for Fast Goal-Directed Arm Movements
,”
J. Hum. Movt. Stud.
, Vol.
6
, pp.
19
37
.
33.
Wilkie
D. R.
,
1954
, “
Facts and Theories About Muscle
,”
Prog. Biophys.
, Vol.
4
, pp.
288
324
.
34.
Wilkie
D. R.
,
1956
, “
The Mechanical Properties of Muscle
,”
Brit. Med. Bull.
, Vol.
12
, pp.
177
182
.
35.
Winters, J. M., 1990, “Hill-Based Muscle Models: A Systems Engineering Perspective,” in: Multiple Muscle Systems: Biomechanics and Movement Organization, J. M. Winters and S. L.-Y. Woo, eds., Springer Verlag, New York, pp. 69–93.
36.
Wood
J. E.
,
Meek
S. G.
, and
Jacobsen
S. C.
,
1989
, “
Quantitation of Human Shoulder Anatomy for Prosthetic Arm Control. II. Anatomy Matrices
,”
J. Biomech.
, Vol.
22
, pp.
309
326
.
37.
Zahalak, G. I., 1992, “An Overview of Muscle Modeling,” in: Neural Prostheses, R. B. Stein, P. H. Peckham, and D. B. Popovic, eds., Oxford University Press, New York, pp. 17–57.
38.
Zajac
F. E.
,
1989
, “
Muscle and Tendon: Properties, Models, Scaling, and Application to Biomechanics and Motor Control
,”
Crit. Rev. Biomed. Engrg.
, Vol.
17
, pp.
359
411
.
This content is only available via PDF.
You do not currently have access to this content.