Anthropometrics II Rad Zdero, Ph.D. University of Guelph

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

Anthropometric Data Tables

Features. Structural Dimensions for U.S. Adults (1989). 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 M F 161.8 cm 149.5 173.6 cm 160.5 184.4 cm 171.3 2. Eye Height 151.1 138.3 162.4 148.9 172.7 159.3 3. Shoulder Height 132.3 121.1 142.8 131.1 152.4 141.9 4. Elbow Height 100.0 93.6 109.9 101.2 119.0 108.8 5. Knuckle Height 69.8 64.3 75.4 70.2 80.4 75.9 See “Static Body Features” Figure 1 for exact dimension

Table 2 - U.S. Adult Civilians (1989) Segment Gender 5 th Percentile 50 th Percentile 95 th Percentile 6. Height (sit) M F 84.2 cm 78.6 90.6 cm 85.0 96.7 cm 90.7 7. Eye Height (sit) 72.6 67.5 73.3 84.4 78.5 8. Elbow Height (sit) 19.0 18.1 24.3 23.3 29.4 28.1 9. Thigh Clearance (sit) 11.4 10.6 14.4 13.7 17.7 17.5 10. Knee Height (sit) 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) M F 54.0 cm 51.8 59.4 cm 56.9 64.2 cm 62.5 12. Thigh-to-Heel Height (sit) 39.2 35.5 44.2 39.8 48.8 44.3 13. Chest Depth (stand) 21.4 24.2 27.6 29.7 14. Elbow-to-Elbow (sit) 35.0 31.5 41.7 38.4 50.6 49.1 15. Hip Width (sit) 30.8 31.2 35.4 36.4 40.6 43.7 See “Static Body Features” Figure 1 for measured dimension

Table 4 - U.S. Adult Civilians (1989) Segment Gender 5 th Percentile 50 th Percentile 95 th Percentile Weight (kg) M F 56.2 kg 46.2 74.0 kg 61.1 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.

Body Segment Lengths [all values are in centimetres] Limb White Male White Female (Percentile) 5 th 50 th 95 th Upper Arm 28.6 30.4 32.3 26.1 27.8 29.5 Forearm 25.9 27.5 29.2 22.7 24.1 25.5 Thigh 40.4 43.2 46.1 36.9 39.5 42.1 Shank 38.9 45.3 34.7 37.4 40.0 L Joint or Hinge Segment

Body Segment Density Body Segment Year = 1860 Year = 1955 Head and Neck 1.11 g/cm3 Trunk -- 1.03 Upper Arm 1.08 1.07 Forearm 1.10 1.13 Hand 1.11 1.16 Thigh 1.05 Lower Leg 1.09 Foot Density = Mass / Volume Human Segment Density ~ 1 g/cm3

Main Segment as % of Total Body Weight Body Segment Weights Main Segment as % of Total Body Weight Individual Segment as % of Main Segment Head and Neck = 8.4 % Head = 73.8 % Neck = 26.2 % Torso = 50 % Thorax (chest) = 43.8 % Lumbar = 29.4 % Pelvis = 26.8 % One Total Arm = 5.1 % Upper Arm = 54.9 % Forearm = 33.3 % Hand = 11.8 % One Total Leg = 15.7 % 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 (%) Year = 1889 1955 1969 Total Body -- 41.2 % Head 43.3 % 46.6 Arm 47 % 43.6 51.3 Forearm 42.1 43 39 Hand 49.4 Total Arm 41.3 Forearm & Hand 47.2 Thigh 44 43.3 Calf (= Shank) 42 37.1 Foot 44.4 42.9 44.9 Total Leg Calf & Foot 52.4 43.7 47.5 C-of-G will normally be closer to the “thicker” proximal end of the segment. L1 L2 Distal End Proximal End

Center of Gravity/Segment Length = L1/L2 (%) C-of-G / Segment Length 0.50 0.506 0.430 0.436 0.433 0.500 C-of-G will normally be closer to the “thicker” proximal end of the segment. L1 L2 Distal End Proximal End Head & Neck Hand Forearm Upper Arm Thigh Leg Foot Trunk [modified from Winter, 1992]

Radius of Gyration/Segment Length = K/L (%) (Cadaver Experiments) Body Segment From Proximal End From Distal End Head, Neck, Trunk 49.7 % 67.5 % Full Arm 54.2 64.5 Forearm 52.6 Hand 58.7 57.7 Forearm and Hand 82.7 56.5 Thigh 54 65.3 Shank 52.8 64.3 Foot 69 Shank and Foot 73.5 57.2 K L Distal End Proximal 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) Measure length, L, of forearm (elbow to wrist) and diameter, d, about half way along length Calculate approx. forearm volume, V = (d/2)2L 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 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

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

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 not necessarily mean avg. leg length and arm length) 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

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?

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 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.