Geometrical and Mass-inertial Characteristics of the Upper Human Limb
Expressions can be evaluated for particular mass
G =
of the whole body in [kg] and height
H =
in [cm]
1. Regression equations for calculation of the segment lengths:
length
expression
value
l
arm
-7.99-0.239*G+0.279*H
l
forearm
-14.54-0.22*G+0.305*H
l
hand
8.78 -0.012*G+0.055*H
2. Regression equations for calculation of the segment masses:
mass
expression
value
m
arm
0.02707*G
m
forearm
0.01615*G
m
hand
0.00614*G
m
arm
-0.142 + 0.029*G
m
forearm
0.165 + 0.0139*G
m
hand
0.109 + 0.0046*G
m
arm
0.25 + 0.03012*G - 0.0027*H
m
forearm
0.3185 + 0.01445*G - 0.00114*H
m
hand
-0.1165 + 0.0036*G + 0.00175*H
3. Location of the gravity center along the longitudinal axis of the respective segment (in percent from the segment length, from the proximal end of the segment to the distal one):
segment
percentage
value
arm
44.98% l
arm
forearm
42.74% l
forearm
hand
36.91% l
hand
4. Central inertial moments of the segments with respect to the sagittal, frontal and proximal axes of these segments (the moments are given in [kg.cm
2
]):
Note that the center of the coordinate system is located in the gravity center, so when the moment equations are written with respect to the joint axis a transformation must be performed!
a. with respect to the saggital axis:
inert. m.
expression
value
I
arm
-250.7 + 1.56*G + 1.512*H
I
forearm
-64.0 + 0.95*G + 0.34*H
I
hand
-19.5 + 0.17*G + 0.116*H
b. with respect to the frontal axis:
inert. m.
expression
value
I
arm
-232 + 1.525*G + 1.343*H
I
forearm
-67.9 + 0.855*G + 0.376*H
I
hand
-13.68 + 0.088*G + 0.092*H
c. with respect to the proximal axis:
inert. m.
expression
value
I
arm
-16.9 + 0.662*G + 0.0435*H
I
forearm
5.66 + 0.306*G - 0.088*H
I
hand
-6.26 + 0.0762*G + 0.0347*H
Average Values
Body Segment
Length in Centimeters
Mass in Kilograms
arm
31.476
1.943
forearm
24.56
1.189
hand
19.938
0.48
upper limb
75.973
3.62
Central Inertial Moments with Respect to
Body Segment
Saggital Axis [kg.cm
2
]
Frontal Axis [kg.cm
2
]
Proximal Axis [kg.cm
2
]
arm
144.33
129.17
40.05
forearm
69.09
64.84
11.98
hand
14.52
9.85
0.011
average whole body height 185.05 [cm] and weight 73.87 [kg]
MotCo Data Project