11 Anthropometrics - Ergo

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Anthropometrics
Anthropometrics
• Standing Working
Heights
• Sitting Working
Heights
• Reaches
• Gender Strength
Differences
• Postural Strength
Differences
Anthropometrics
Design so the large can
fit, the small can reach
and the weak can lift,
lower, push, pull and
carry.
Anthropometric Measurements
Anthropometrics looks at the
variability between people and utilizes
principles of statistics to do this.
Percentiles
• Body dimensions can be
plotted on a graph with the
measurements on the
horizontal x axis
increasing toward the right
from the zero point. The
frequency of occurrences
is plotted on the vertical y
axis, increasing toward the
top from the zero point.
Anthropometrics and Design
• It is not customary to
design for everyone. The
military has chosen to
exclude 5% at the small
end of the curve and 5%
at the large end of the
curve, thereby
accommodating 90 of the
measured population in
the Military Standards
Anthropometric Measurements
Anthropometric Measurements
Dimension
5th
50th
95th
Male
Female
Male
Female
Male
Female
Standing Vertical Grip Reach
76.8
71.1
81.9
75.8
87.0
80.5
Standing Forward Grip Reach
28.5
25.8
30.9
28.0
33.3
30.1
Height
64.6
59.8
69.1
64.0
73.6
68.1
Eye Height
62.8
55.9
67.3
60.0
71.9
64.2
Shoulder Height
52.4
48.2
56.7
52.2
61.0
56.1
Elbow Height
40.2
37.2
43.5
40.2
46.9
43.1
Sitting Vertical Grip Reach
45.5
42.1
49.4
45.7
53.4
49.2
Sitting Height
33.7
31.5
36.0
33.9
38.4
36.2
Sitting Eye Height
29.1
27.2
31.5
29.5
33.9
31.9
Sitting Elbow Height
7.7
7.3
9.7
9.3
11.6
11.2
Adapted from: Pheasant, Stephen, (1996). “Bodyspace: Anthropometry, Ergonomics and the
Design of Work”, Bristol, PA: Taylor & Francis.
Anthropometrics
• 50th Percentile Male
Reach = 30.9”
• 50th Percentile Female
Reach = 28.0”
• 95th Percentile Male
Reach = 33.3”
• 5th Percentile Female
Reach = 25.8”
Things To Consider
•
•
•
•
•
Determine what body dimensions are relevant.
Determine what population group is relevant.
Use the anthropometric data as a guide and a
place to start. It does not replace employee input.
Just because something does not fall within
anthropometric guidelines does not mean it is
necessarily a significant ergonomic risk.
When designing workstations or equipment, you
will never be able to accommodate everyone. Try
to accommodate as much of the population as you
can, given the space and cost parameters you
have to work within.
Standing Workstation Height
NIOSH 1997 Publication, Elements of Ergonomics Programs
Horizontal Reach Envelopes
NIOSH 1997 Publication, Elements of Ergonomics Programs
Choosing Working Postures
• Standing
– For heavy, bulky loads
– When frequent
movement is required
– When there is no knee
room under the
equipment
– Where there is limited
front-rear space
Choosing Working Postures
• Sitting
– For accurate control, fine
manipulation.
– For continuous light
manipulation work.
– For close visual work with
prolonged attention.
– For limited headroom, low
work heights.
Sagittal Reach Envelopes
• As the arm moves though its
normal range of motion it creates
an arc and creates the primary
reach arc and the secondary reach
arc. The primary reach arc places
minimal stress on the shoulder and
low back. The secondary reach
envelope can place stress on the
shoulder and increases stress on
the low back. Reaching beyond
the secondary reach arc will
require forward bending and
significantly increases stress on
the low back.
Strength Variability:
Females vs. Males
Body Part
Percent Strength of
Females vs. Males
Arms
60 %
Trunk
64%
Legs
72%
Male Grip Strength & Age
Male (lbs)
Percentiles
18 - 29
30 - 39
40 - 49
50 - 59
60 - 69
70 - 79
5
75.2
88.0
84.4
78.3
70.5
-
25
93.7
101.2
97.7
93.7
82.5
70.1
50
110.9
112.0
108.0
102.5
90.4
80.5
75
123.5
124.6
121.3
112.4
100.3
88.4
95
144.0
144.6
134.5
132.1
113.5
100.5
Mean
110.2
113.8
109.0
102.1
90.6
76.9
Adapted from: Australian Fitness Norms, 1992, The Health Development Foundation, Adelaide,
p.32.
Female Grip Strength & Age
Female (lbs)
Percentiles
18 - 29
30 - 39
40 - 49
50 - 59
60 - 69
70 - 79
5
52.0
49.6
49.6
40.8
38.6
-
25
62.8
61.7
59.5
54.0
50.3
47.6
50
66.8
68.3
66.1
63.9
55.1
55.1
75
75.0
76.1
72.8
70.5
61.7
59.5
95
85.5
88.2
83.8
78.3
74.7
67.2
Mean
68.0
69.0
66.4
61.3
55.6
51.4
Adapted from: Australian Fitness Norms, 1992, The Health Development Foundation, Adelaide,
p.32.
Posture Dependent Strength
Variability
Ear-Eye-Line
• The EE line is determined by using the ear-hole
and the junction of the eyelids. The EE line
describes the posture of the head and serves as
reference for the angle of the line of sight.
Line of Sight
• The line of sight connects the pupil with
the visual target. Eye movement within
about 15 degrees above and below the
average line-of-sight angle is still
comfortable.
Practical Application of
Anthropometrics
• This video clip
from NASA
shows how
Anthropometri
c data was
applied to the
design of
equipment.
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