CH 6 Anthropometry (copy)

what is the way of the ergonomist

modify the task to fit the person

anthropometry

measurement of the dimensions and other physical characteristics of the body

percentile

value that defines the percentage of measurements that are at or below that value

covariation

as one measure changes, so does another - sample correlation coefficient (r )

coefficient of determination

portion of the dependent variable accounted for by the independent variable

how are measurements defined

defined according to specified points - anatomical landmarkers

measurement tools

• anthropometer: graduated rod w sliding right angle, measure lengths

• Calipers: measure short lengths, skin folds

• cone: grip diameter

Anatomical view from the side

sagittal

anatomical view from the front

frontal

measurements in motion

• extremities: reaches, lengths

• trunk: rotation, angle

• hands: functional movements

what are some difficulties

• points unrelated in space

• Not 3D

• end points contact difficult

• summation does not yield final dimension

design considerations

• fitting: if fit the largest, smallest can use

• reaching: if we accommodate the smallest, largest can also reach

• adjustability

workstation

any environment the user is supposed to perform a task in

work envelope

zone of convenient reach of normal working area

design for person

when the task is small and general - only done by a single person

design for task

when task is specific, repetitive, done by multiple people

seated work stations

adv: moderate energy demands, body weight partially supported, accommodate back muscles

disadv: limited workspace, generate less strength, less stress spine

seated guidelines

do use: controlled hand movements, foot controls

do not use: large forces, large work areas, need leg room

standing workstations

adv: gravity spine + pelvis alignment, large range of motion, dynamic tasks

disadv: higher energy demands, blood pools lower extremeties, flexion torque ankles

standing guidelines

do use: large area of focus/work area

do not use: high work, beyond sitting reach, stand for extreme lengths of time

potential safety hazards

cutting: contact with sharp edge, poor finish

shearing: linear motion along sharp edge, two moving object pass w contact,

crushing: caught behind two sharp objects

seat height

Critical Anatomical Landmark: Popliteal height (back of the knee)

Measurement: The distance from the floor to the underside of the thigh at the back of

the knee

minimize accident

prevent contact

avoid changes

regular maintenance

seat depth

buttock-popliteal length: butt to the back of the knee

desk height

elbow height

desk depth

forearm length.