Anthropometric Measurements By Majed Awad

Introduction With the increased objective of creating more efficient man-machine systems, the need to collect extensive anthropometric data becomes more important. Consequences of designing systems that do not accommodate for user populations include user fatigue, task inefficiency and are generally inconvenient.

Articles Presented T.J. Galloway and M.J. Fitzgibbon (1991). Some anthropometric measures on an Irish population. Applied ergonomics 1991, 22.1, M.H. Al-Haboubi. Anthropometry for a mix of different populations. Applied ergonomics 1990, vol. 23.

Summary (Gallwey and Fitzgibbon) Population studied 164 males Mean age 29.2 Age range 17 – 58 Wore normal work clothes except for jackets and shoes Apparatus Harpenden anthropometer

Dimensions Measured (Gallwey and Fitzgibbon) Data for 11 dimensions relevant to workplace design were collected:

Dimensions Measured 1. Body mass: subject stood erect on a medical scale reading to 0.1kg. 2. Stature: subject stood erect heels together, looked straight ahead, arms hung loose at the sides. 3. Popliteal height: subject sat erect on the bench, feet height was adjusted to bring thighs horizontal and parallel, lower legs vertical – vertical height from foot surface to top surface of bench. 4. Knee height: subject same as (3) – vertical height from foot surface to superior aspect of right patella. 5. Thigh clearance height: subject same as (3) – vertical height from top surface of bench to the junction of thigh and abdomen. 6. Buttock-knee length: subject same as (3) – horizontal distance from block held against rearmost part of buttocks to edge of right patella.

Dimensions Measured 7. Buttock-Popliteal length: as for (6) – horizontal length to front edge of bench. 8. Buttock breadth – seated: as for (3) – horizontal width across the greatest lateral protrusion on each side of the buttocks. 9. Sitting height – normal: subject sat normally relaxed on the bench hands in lap, looking straight ahead – vertical height from top surface of bench to top middle part of the head. 10. Sitting height – erect: subject sat as in (9) – helped if necessary by a gentle push in the sacral area of the back – vertical height as in Elbow – elbow breadth: subject sat erect, upper arms hanging at sides, lower arms extended horizontally, palms facing each other, elbows held as tightly as possible to the sides – maximum horizontal distance across lateral surface of the elbows.

Results (Gallwey and Fitzgibbon)

Comparisons With U.S. Population (Gallwey and Fitzgibbon) Compared with U.S. Survey, Stoudt (1965) Found that on most dimensions, there were significant differences in the anthropometric measurements. Differences due to: 1. For U.S. data, only 5th and 95%tiles were available. Thus assumed that these points were 3.29 standard deviations from the means of a normal distribution. 2. Differences in clothing - U.S. subjects stripped to the waist, emptied their pockets and wore short gowns.

Summary (Al-Haboubi) Population studied 408 males Mean age 27 Age range Subject dressed in light fabric clothing and did not wear shoes Apparatus University designed anthropometric device consisting of sliding vertical and horizontal dimensional scales. Sliding bench.

Population Studied (Al-Haboubi1990) When designing for a certain population, age, sex, or race should not be used as the base for the user population (al-Haboubi 1990). The collective mixture of people who may have different sex, age, race or occupation should be identified as the user population and anthropometric designs should be based on their characteristics as one group.

Dimensions Measured Data for 19 body dimensions relevant to the design of chairs were measured:

Results (Al-Haboubi1990) Most of the body dimensions followed normal distribution. Weight, max body depth, buttock – Popliteal length, max body breadth, thigh clearance, elbow height, and hand breadth all deviate from normality. Reason cited: sample was drawn from non- homogeneous mix of nationalities. Thus %tiles for these dimensions were found by counting.

Comparisons to Other Populations (Al-haboubi1990) Compared stature, weight, sitting height between easterners and those countries that export man-machine systems to Saudi. Found that there are statistically significant differences in almost all comparisons. Caution must be taken when developing countries import systems such as elevators from other countries.

Comparing the articles Measurements were taken with different postures. Al-Haboubi focused on chair design postures, Gallwey and Fitzgibbon focused on worker postures. Gallwey and Fitzgibbon focused their study on a local homogeneous male population with wide age range. Al-Haboubi focused his study on a local non- homogeneous population with a wide age range. No females were used in either study.

Limitations (Gallwey and Fitzgibbon) Static anthropometric data collected. -Limited application to real-world working postures. Comparisons based on statistical estimations and thus are not highly accurate. Assumed U.S. Data followed a normal distribution. As al-Haboubi demonstrated, this assumption depends on another assumption: population being studied is homogeneous.

Limitations (Al-Haboubi) Did not state how body dimensions were measured. No comparison made to homogeneous local population. Limited comparison with other populations (only examined stature, weight and sitting height). No females used in study.

Future studies Collect functional anthropometric data for homogeneous and non-homogenous populations. Collect anthropometric data for different age groups to see whether there is a significant difference. Possibly find reach envelopes for populations for use in systems design. Include females in study.

Questions