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Anthropometrics II Rad Zdero, Ph.D. University of Guelph
Anthropometric Data Tables Example Using and Generating Anthropometric Data Ergonomic Design Principles Ergonomic Design Approach Outline
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 4 - U.S. Adult Civilians (1989) SegmentGender5 th Percentile 50 th Percentile 95 th Percentile Weight (kg)MFMF 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 Limb White MaleWhite Female (Percentile) 5 th50 th95 th5 th50 th95 th Upper Arm28.630.432.326.127.829.5 Forearm25.927.529.222.724.125.5 Thigh40.4184.108.40.2069.542.1 Shank38.942.145.334.737.440.0 [all values are in centimetres] L Joint or Hinge Segment
Body Segment Density Body SegmentYear = 1860Year = 1955 Head and Neck1.11 g/cm 3 Trunk--1.03 Upper Arm1.081.07 Forearm1.101.13 Hand1.111.16 Thigh1.071.05 Lower Leg1.101.09 Foot1.091.10 Density = Mass / Volume Human Segment Density ~ 1 g/cm 3
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 (%) SegmentYear = 1889 19551969 Total Body-- 41.2 % Head--43.3 %46.6 Arm47 %43.651.3 Forearm42.14339 Hand--49.4-- Total Arm-- 41.3 Forearm & Hand47.2-- Thigh4443.3-- Calf (= Shank)4243.337.1 Foot44.442.944.9 Total Leg--43.3-- Calf & Foot52.443.747.5 C-of-G will normally be closer to the “thicker” proximal end of the segment. L1 L2 Distal End Proximal End
[modified from Winter, 1992] Segment Head & Neck C-of-G / Segment Length 0.50 0.506 0.430 0.436 0.433 0.500 Hand Forearm Upper Arm Thigh Leg Foot Trunk Center of Gravity/Segment Length = L1/L2 (%) C-of-G will normally be closer to the “thicker” proximal end of the segment. L1 L2 Distal End Proximal End
Radius of Gyration/Segment Length = K/L (%) (Cadaver Experiments) Body SegmentFrom Proximal End From Distal End Head, Neck, Trunk49.7 %67.5 % Full Arm54.264.5 Forearm52.664.5 Hand58.757.7 Forearm and Hand82.756.5 Thigh5465.3 Shank52.864.3 Foot69 Shank and Foot73.557.2 K L Distal End Proximal End K
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.Measure length, L, of forearm (elbow to wrist) and diameter, d, about half way along length 2.Calculate approx. forearm volume, V = (d/2) 2 L 3.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.Calculate forearm C-of-G using C-of-G/Length ratio table 5.Calculate forearm radius of gyration, K, using forearm length, L, and “Radius of Gyration” table
Forearm Data Table DimensionSymbolValue (female) Value (male) LengthL Closest %ile for Length% Diameterd VolumeV Mass (from density formula, D = m/V) m Mass (from “Body Segment Weight” table) m C-of-G (from elbow)C-of-G Radius of Gyration (from elbow) K
Ergonomic Design Principles 1.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
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.Determine important body dimensions 2.Define population group (men, kids, Swedes?) 3.Decide on which design principles will be used (design for extremes, average, adjustment?) 4.Select which sub-group of pop. group will be designed for (5th, 50th, 73rd, %ile?) 5.Extract values from Anthropometric Tables 6.Add dimensional allowances for any clothing, equipment, safety precautions, and task performance. 7.Build “prototype” or “mock up” of product, device, procedure, or facility. 8.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.