Anthropometrics II

Rad Zdero, Ph.D.

University of Guelph

Outline

• Anthropometric Data Tables • Example • Using and Generating Anthropometric Data • Ergonomic Design Principles • Ergonomic Design Approach

Anthropometric Data Tables

Figure 1.

Static Body Features. Structural Dimensions for U.S.

Adults (1989).

(see also Figure 2 and Tables 1 to 4 for Values) [source: Kroemer, 1989]

Figure 2. Percentile of Population Group

Normal or Gaussian Data Distribution

No. of Subjects

5th percentile = 5 % of subjects have “dimension” below this value 50 % 95 %

Dimension (e.g. height, weight, etc.)

Table 1 - U.S. Adult Civilians (1989)

Segment Gender 5 th Percentile 50 th Percentile 95 th Percentile

1. Stature 2. Eye Height 3. Shoulder Height 4. Elbow Height 5. Knuckle Height M F M F M F M F M F 161.8 cm 149.5

151.1

138.3

132.3

121.1

100.0

93.6

69.8

64.3

173.6 cm 160.5

162.4

148.9

142.8

131.1

109.9

101.2

75.4

70.2

See “Static Body Features” Figure 1 for exact dimension 184.4 cm 171.3

172.7

159.3

152.4

141.9

119.0

108.8

80.4

75.9

Table 2 - U.S. Adult Civilians (1989)

Segment Gender 5 th Percentile 50 th Percentile 95 th Percentile

6. Height (sit) 7. Eye Height (sit) M F M F 84.2 cm 78.6

72.6

67.5

90.6 cm 85.0

78.6

73.3

96.7 cm 90.7

84.4

78.5

8. Elbow Height (sit) 9. Thigh Clearance (sit) M F M F 19.0

18.1

11.4

10.6

24.3

23.3

14.4

13.7

29.4

28.1

17.7

17.5

10. Knee Height (sit) M F 49.3

45.2

54.3

49.8

59.3

54.5

See “Static Body Features” Figure 1 for exact dimension

Table 3 - U.S. Adult Civilians (1989)

Segment Gender 5 th Percentile 50 th Percentile 95 th Percentile

11. Buttock-to Knee (sit) 12. Thigh-to Heel Height (sit) 13. Chest Depth (stand) 14. Elbow-to Elbow (sit) 15. Hip Width (sit) M F M F M F M F M F 54.0 cm 51.8

39.2

35.5

21.4

21.4

35.0

31.5

30.8

31.2

59.4 cm 56.9

44.2

39.8

24.2

24.2

41.7

38.4

35.4

36.4

64.2 cm 62.5

48.8

44.3

27.6

29.7

50.6

49.1

40.6

43.7

See “Static Body Features” Figure 1 for measured dimension

Table 4 - U.S. Adult Civilians (1989)

Segment

Weight (kg)

Gender

M F

5 th Percentile

56.2 kg 46.2

50 th Percentile

74.0 kg 61.1

95 th Percentile

97.1 kg 89.9

See “Static Body Features” Figure 1 for measured dimension

Note for Tables 1-4:

Due to anatomical reasons, Male data is larger than Female data at all %iles, with the exception of #13 (Chest Depth) and #15 (Hip Width), which shows a reversal of this trend.

Limb

Upper Arm Forearm Thigh Shank

Body Segment Lengths

[all values are in centimetres]

White Male White Female (Percentile) (Percentile) 5 th

28.6

25.9

40.4

38.9

50 th

30.4

27.5

43.2

42.1

95 th

32.3

29.2

46.1

45.3

L 5 th

26.1

22.7

36.9

34.7

50 th

27.8

24.1

39.5

37.4

95 th

29.5

25.5

42.1

40.0

Segment

Joint or Hinge

Body Segment Density

Body Segment

Head and Neck Trunk Upper Arm Forearm Hand Thigh Lower Leg Foot

Year = 1860

1.11 g/cm 3 - 1.08

1.10

1.11

1.07

1.10

1.09

Year = 1955

1.11 g/cm 3 1.03

1.07

1.13

1.16

1.05

1.09

1.10

Density = Mass / Volume

Human Segment Density ~ 1 g/cm 3

Body Segment Weights

Main Segment as % of Total Body Weight

Head and Neck = 8.4 % Torso = 50 % One Total Arm = 5.1 % One Total Leg = 15.7 %

Individual Segment as % of Main Segment

Head = 73.8 % Neck = 26.2 % Thorax (chest) = 43.8 % Lumbar = 29.4 % Pelvis = 26.8 % Upper Arm = 54.9 % Forearm = 33.3 % Hand = 11.8 % Thigh = 63.7 % Shank = 27.4 % Foot = 8.9 %

Centre of Gravity

Relative location of C-of-G’s on body segments.

See the C-of-G %-iles in the next table [Dempster, 1955]

Centre of Gravity

Center of Gravity/Segment Length = L1/L2 (%)

Segment

Total Body Head Arm Forearm Hand Total Arm Forearm & Hand Thigh Calf (= Shank) Foot Total Leg Calf & Foot

Year = 1889

- - 47 % 42.1

- - 47.2

44 42 44.4

- 52.4

1955

- 43.3 % 43.6

43 49.4

- - 43.3

43.3

42.9

43.3

43.7

1969

41.2 % 46.6

51.3

39 - 41.3

- - 37.1

44.9

- 47.5

Proximal End L1 L2 Distal End

C-of-G will normally be closer to the “thicker” proximal end of the segment.

Center of Gravity/Segment Length = L1/L2 (%)

Segment Head & Neck Hand Forearm Upper Arm Thigh Leg Foot Trunk C-of-G / Segment Length 0.50

0.506

0.430

0.436

0.433

0.433

0.500

0.500

Proximal End L1 L2 Distal End

C-of-G will normally be closer to the “thicker” proximal end of the segment.

[modified from Winter, 1992]

Radius of Gyration/Segment Length = K/L (%)

(Cadaver Experiments) Body Segment

Head, Neck, Trunk Full Arm Forearm Hand Forearm and Hand Thigh Shank Foot Shank and Foot

From Proximal End

49.7 % 54.2

52.6

58.7

82.7

54 52.8

69 73.5

From Distal End

67.5 % 64.5

64.5

57.7

56.5

65.3

64.3

69 57.2

Proximal End

K L K

Distal End

Example – Anthropometric Forearm Data

•

Purpose

Become accustomed to Generating and Using Anthropometric Data tables and formulas.

Steps (Use ruler or tape measure for length measurement)

1.

2.

3.

Measure length, L, of forearm (elbow to wrist) and diameter, d, about half way along length Calculate approx. forearm volume, V =  (d/2) 2 L Calculate forearm mass, m, in two ways … (do they match?) • using m = D x V and density from Density Table • using “Body Segment Weights” table 4.

5.

Calculate forearm C-of-G using C-of-G/Length ratio table Calculate forearm radius of gyration, K, using forearm length, L, and “Radius of Gyration” table

Length

Forearm Data Table

Dimension Symbol Value (female)

L Closest %ile for Length Diameter Volume Mass (from density formula, D = m/V) Mass (from “Body Segment Weight” table) C-of-G (from elbow) Radius of Gyration (from elbow) % d V m m C-of-G K

Value (male)

• • • •

1.

Ergonomic Design Principles

Designing for the Average

There is no “average” person Very difficult to find person who is average in more than a few dimensions (e.g. avg. height may mean avg. leg length and arm length)

not

necessarily Designing for the average can be an over-simplification Only to be done after careful evaluation (e.g. very specific subgroup)

e.g. Clothing Study (n = 4096 people) Center 30% was taken as Avg. Percentile, BUT…

Only 26% were of Avg. Height Only 7.4% had Avg. Chest Circumference Only 3.5% had Avg. Sleeve Length Only 0.07% had Avg. Waist Circumference And 0% had Avg. Foot Length

2.

Designing for the Extremes

Principle

• Try to accommodate entire population group

Maximum Levels

• e.g. doorways, size of escape hatches on military aircraft, strength of ladders and workbenches

Minimum Levels

• e.g. distance of control button from operator, force required to operate control lever or button

Practical Design Range

• use 5th and 95th percentiles of pop. group as extremes • use smallest female and largest male

Questions

• Effects on those excluded?

• Can we restrict users to a certain pop. group?

3.

Designing for Adjustment

Principle

• Try to allow for adjustments in size, shape, position, intensity, and duration of the product, device, procedure, or system to accommodate unexpected circumstances

Practical Design Range

• Common to use 5th %ile female and 95th %ile male • Results in accommodation of 95% (not 90%) of 50/50 male/female pop. group because of overlap in male and female body dimensions

Examples

• Car seats, desk height, footrests, office furniture

Questions

• Use: one shot vs. continual?

• • • Use: one user or shared?

Ease of and Training for using “adjustments”?

What happens if design range misused?

Ergonomic Design Approach

1.

2.

3.

4.

5.

6.

7.

8.

Determine important body dimensions Define population group (men, kids, Swedes?) Decide on which design principles will be used (design for extremes, average, adjustment?) Select which sub-group of pop. group will be designed for (5th, 50th, 73rd, %ile?) Extract values from Anthropometric Tables Add dimensional allowances for any clothing, equipment, safety precautions, and task performance.

Build “prototype” or “mock up” of product, device, procedure, or facility.

Test prototype with human subjects.

Sources Used

• Chaffin et al.,

Occupational Biomechanics

, 1999.

• Dempster,

Space Requirements of the Seated Operator

, 1955.

• Hay and Reid, 1988.

• Kreighbaum & Barthels,

Biomechanics: A Qualitative Approach for Studying Human Movement

, 1996.

• Kroemer, “Engineering Anthropometry”,

Ergonomics

, 32(7):767-784, 1989 • Sanders and McCormick,

Human Factors in Engineering and Design,

1993.

• Moore and Andrews,

Ergonomics for Mechanical Design

, MECH 495 Course Notes, Queens Univ., Kingston, Canada, 1997.

• Oskaya & Nordin,

Fundamentals of Biomechanics

, 1991.

• Winter,

Biomechanics of Human Movement

, 1992.