LITERATURE
FBWM 76-2, FBWM 76-2, Bonn
6. CONCLUSION
The existing, overall, worldwide, anthropometric data base, though clearly adequate for some specialized purposes on some spe- cialized populations, needs to be expanded to meet additional pres- ent needs, as well as an anticipated expansion of future needs. More anthropometric and biomechanical information is needed on a variety of different general populations, and specialized sub-populations.
Mathematical modelling and the prediction of data from existing mea- surements should play an increasingly important role in the future, as will the development of new data gathering techniques.
REFERENCES
Abraham, S., Johnson, C.L., and Najjar, M.F., 1979, Weight and height of adults 18-74 years of age, Vital and Health Statistics, Series II-Number 211.
Annis, J.F., 1978, Variability in human body size, in Volume I:
Anthropometry for Designers, Anthropometric Source Book, NASA, Reference Publication 1024, Houston, Texas.
Churchill, E., and McConville, J.T., 1976, Sampling and Data Gathering Strategies for Future USAF Anthropometry, AMRL-TR-74-102, Wright-Patterson Air Force Base, Ohio.
Churchill, E., Churchill, T. and Kikta, P., 1977, The AMRL Anthropo- metric Data Bank Library: Volumes I-V, AMRL-TR-77-1, Wright- Patterson Air Force Base, Ohio.
Churchill, E., McConville, J.T., Laubach, L.L., and White, R.M., 1971, Anthropometry of U.S. Army Aviators--1970, TR-72-52-CE, U.S.
Army Natick Laboratories, Natick, Mass.
Clauser, C.E., Tucker, P.E., McConville, J.T., Churchill, E. Laubach, L.L., and Reardon, J.A., 1972, Anthropometry of Air Force Women, AMRL-TR-70-5, Wright-Patterson Air Force Base, Ohio.
Damon, A. and Stoudt, H.W., 1963, The functional anthropometry of old men, Human Factors, 5:485-491, 1963.
Damon, A., Stoudt, H.W., and McFarland, R.A., 1966, The Human Body in Equipment Design, Harvard University Press, Cambridge, Mass.
54 H.W.STOUDT Friedlaender, J.S., Costa, P.T., Bosse, R., Ellis, E., Rhoads, J.G.,
and Stoudt, H.W., 1977, Longitudinal physique changes among healthy white veterans at Boston, Human Biology, 49:541-558.
Hamill, P.V.V., Johnson, C.L., Reed, R.R., and Roche, A.F., 1977, NCHS growth curves for children birth-18 years, Vital and Health Statistics, Series II-Number 165.
Laubach, L.L., McConville, J.T., and Tebbetts, I, 1978, Volume III:
Annotated Bibliography of Anthropometry, Anthropometric Source Book, NASA Reference Publication 1024, Houston, Texas.
Snyder, R.G., Spencer, M.L., Owings C.L., and Schneider, L.W., 1975, Anthropometry of u.S. Infants and Children, SP-394, Society of Automotive Engineers, Detroit, Michigan.
Stoudt, H.W., Are people still getting bigger--who, where, and how much?, 1979, pp. 1290-1284, 1978 Transactions, Society of Automotive Engineers, Warrendale, Pa.
Stoudt, H.W., Damon, A., and McFarland, R.A., 1960, Heights and weights of white Americans, Human Biology 32:331-341.
Stoudt, H.W., Damon, A., McFarland, R.A., and Roberts, J., 1965, Weight, height and selected body dimensions pf adults, United States 1960-1962, Vital and Health Statistics, Series II, Number 8.
Thornton, W.E., 1978, Anthropometric changes in weightlessness, 1978, in Volume I: Anthropometry for Designers, Anthropometric Source Book, NASA Reference Publication 1024, Houston, Texas.
White, R.M., 1964, Anthropometric Survey of the Armed Forces of the Republic of Vietnam, U.S. Army Natick Laboratories, Natick, Mass.
White, R.M., 1978, Anthropometry and human engineering, Yearbook of Physical Anthropology 1978, American Association of Physical Anthropologists, Washington, D.C.
ANTHROPOMETRIC AND BIOMECHANICAL DATA ACQUISITION AND APPLICATION TO REHABILITATION ENGINEERING
Robert D. Dryden Virginia Polytechnic Institute and State University
Blacksburg, Virginia INTRODUCTION
John H. Leslie, Jr., and Roy H. Norris
Rehabilitation Engineering Center
Wichita State University Wichita, Kansas
It can be stated without fear of contradiction that, in the United States, severely disabled people have not been able to take their rightful place in American society. Opportunities in the vocational, educational, transportation and independent living areas have simply not been available to the severely physically disabled population. In 1972, a research effort was initiated in Wichita, Kansas, under the joint auspices of the Cerebral Palsy
Research Foundation of Kansas, Inc., and the College of Engineering, Wichita State University, to attempt to correct this situation. In the researchers' minds, it is necessary to integrate a wide variety of programs into a service delivery system in order to respond to the needs of severely handicapped people to create a total life- style. A person's life should not be considered as a series of independent needs but as an integrated hierarchy of human aspirations.
In order to implement this research, it became necessary to quantify measures of the physical capabilities of handicapped persons. There is a dirth of anthropometric and biomechanica1 data related to handicapped people. The handicapped population served by this research effort is primarily cerebral palsied persons and those individuals who have suffered brain damage either through trauma or congenitally. It became painfully clear during the initial stages of the research that some sort of objective means of determining the residual capability of handi- capped persons was needed. To respond to this need, the research
55
56 R. D. DRYDEN ET AL.
project developed an apparatus called the AMI (Available Motions Inventory). It is designed to determine, in objective rather than subjective terms, the physical capability of handicapped persons in order that they may be productive in vocational, educational, transportation, and independent living environments.
The purpose of this paper is to expand on this theme to
acquaint the reader with the Available Motions Inventory apparatus.
It should be realized that the research project is a pragmatic one.
The results of the research are applied on an everyday basis to the problems confronting handicapped people. The basis of the research is to place "real, live, flesh and blood human beings" on the job, in the classroom, or in their own apartment. Therefore, the research is not theoretical but is practical and has application to a wide variety of barriers limiting the alternatives of handi- capped persons. In many cases, it is felt that the research has theoretical implications, i.e., the study of the therapeutic
effect of work. However, prior to the present time, the researchers have been more involved with the development of service delivery systems for severely handicapped people rather than theoretical laboratory investigation.
METHODS Rationale
It is fairly common practice for broad classifications
established by medical diagnosis to be carried over into rehabili- tation and job placement efforts. It is immediately obvious that these categories provide a qualitative description of the physical disability. These descriptions are useful in the medical and therapeutic treatment where there is a need to identify the pathol- ogy or disability for purposes of correction. In finding employ- ment for the handicapped, however, a quantitative measure of a person's physical capabilities is essential. This is the basis for the Available Motions Inventory (AMI) as developed at Wichita State University by what is now designated as the Rehabilitation Engineering Center under the sponsorship of the Cerebral Palsy Research Foundation of Kansas.
The Available Motions Inventory samp~es a variety of physical tasks which are typically required in performing jobs in an
industrial setting.
Limiting evaluation items to industrially related tasks is not meant to preclude expansion of the system to other job areas.
Naturally, some overlap of tasks will occur so that many of the industrially related evaluative devices as presently developed will serve for other job areas as well.
REHABILITATION ENGINEERING 57 Evaluation Hardware
The devices which have been devised to evaluate a client's physical capabilities fall into two main categories: controls and assembly. The names given to the controls and assembly categories are not meant to imply that the information yielded by the devices in these categories applies exclusively to machine control or to assembly-job capabilities respectively. The information provided
FIGURE 1. AMI Device
by either can have significance for both production and assembly types of industrial jobs. A modular design was adopted for these devices as shown in Figure 1. This concept allows for ready testing at various positions relative to the client. The modules were fabricated to permit evaluation of capability in using one or more machine controls. The controls included on the modules were
selected on the basis that they constitute a representative sample of typical machine controls found in industry. The base of each
58 R. D. DRYDEN ET AL.
module is a one foot square aluminum panel. The machine control is on the front face of the plate and the mechanical and electronic hardware used in measuring the client's response is in the rear.
Capability Evaluation
The client's capability to perform industrial tasks is evaluated by the analysis of scores recorded on seventy-one sub- tests. These are divided into six groups to facilitate record keeping and data processing. A listing of these groups and their subtests are as follows:
Switches:
Settings:
Rate:
Strength:
Assembly:
Reaction:
Slide, Rotary, Detent, Toggle, Pushbutton Crank, Balance Crank, Handknob
Crank, Balance Crank, Handknob, Footpeda1 Pinch, Grip, Applied Torque, Applied Force Plates, Spacers, Flat Washers, Lock Washers, Hex Nuts, Grommets, Positioning, Bolts, Drill
Hand
A brief description of experimental procedures is given below.
Equipment Set-Up and Data Acquisition
A. Record by checking the appropriate box whether the client is ambulatory or is confined to a wheelchair.
B. Popliteal height
1. Seat the client in any standard chair so that the client's lower legs are perpendicular to the floor with several inches clearance between the back of the lower leg and the front lip of the chair. The feet
shou1~ be placed flat on the floor and the client should be asked to sit erect.
2. Measure and record the client's left and right popliteal height. If the client's lower legs are significantly different lengths, measure and record.
the longer of the two. Make a note on the Record in the case of significantly different lengths.
3. Place the test chair or client's wheelchair centered laterally in front of the AMI frame. If an adjustable height chair is available, adjust the seat height (front edge) equal to or slightly less than popliteal height.
REHABILITATION ENGINEERING 59
c.
Seated elbow height1. With the subject sitting erectly in chair or wheel- chair, measure and record the right seated elbow height. For this measurement, the arm is flexed at the elbow to 900 and is positioned so that the upper arm is perpendicular to the floor. The distance to be measured is the distance from the floor to the lower surface of the ulna at the elbow joint.
Reach
2. Repeat for left elbow height.
D. Determine and record the client's preferred hand. This may be done by observation during the test if the client
is unable to respond to such a question. If the client shows no preference, enter "NONE" in the appropriate space.
A. Horizontal functional reach
1. Set the vertical position of the AMI frame so that the top surface of the horizontal frame is equal to or slightly above the average of the two measured elbow heights. (If the left and right elbow heights are different by more than two inches, different AMI frame height adjustments must be made for all sub- sequent left and right handed measurements.) Instrumentation
The data acquisition scheme for the AMI is divided into two main categories. Data for pinch, grip, switch settings, dial settings, and pushbutton operation is obtained by visual obser- vation of the pinch and grip guages and by visual observation of the dial and switch settings.
Data for the tests involving the measurement of torque utilize strain guages with appropriate electronic instrumentation which converts the strain to voltage which is read by means of a digital voltmeter.
Data involving the counting of either rotations or hits and misses as in the case of the drill simulator is obtained by means of electronic counters. In the case of the rotation counter, the scheme also includes a ten-second clock which is connected such that once the handwheel is moved such that a single pulse is
60 R. D. DRYDEN ET AL.
obtained from the photo-interrupter, a ten-second period is begun.
The display unit will then indicate the number of revolutions of the handwheel that takes place within ten seconds of the initial interrupter pulse. Timing of intervals required to achieve switch settings, dial settings, and assembly tasks is performed by the evaluator's observation of the activity and use of a standard stop- watch.
FIGURE 2. Reaction Reach Timing Device
Timing of an individual's reaction time and time required to reach a given distance supplements the timed items of the Available Motions Inventory; it is particularly useful in analyzing the activities required to achieve the assembly items.
The test client's hand rests on a pedal switch. The client is directed to respond to an auditory stimulus, a buzzer, by releasing the pedal switch, reaching to a similar switch and depressing the second switch. Time required to release the first
REHABILITATION ENGINEERING 61 switch as well as the time required to reach the second switch and depress it are measured electronically in decimal seconds. These measured increments of time are called reaction time and reach time, respectively.
Motions started from a position directly in front of the seated client reaching to the side and a more remote position directly in front are timed with each hand as well as these same positions in reverse order. The former items sample extension movements;, the latter items sample flexion movements. These two classes of neuromuscular activity may be distinctively different
in a handicapped person.
Data evaluation involves the comparison of the test client's mean score on each subtest with a set of standard data. The standard data is the mean score achieved by a group of thirty able-bodied persons on the various subtests. This provides a direct comparison of the individual test client to a standard score. Standard deviation refers to the variability of performance achieved by the client on repeated trials of a subtest. Z-score refers to the number of standard deviations difference between the client's mean score and the standard's mean score. A positive Z-score indicates performance better than the standards group. A Z-score ranging from -3.00 to zero would indicate that the client could perform that class of tasks with no engineering modifications to the work environment. Negative Z-scores larger than -3.00 would indicate that a client could not perform such tasks without
engineering adaptive devices. See Appendix for samples of computer printouts.
RESULTS AND CONCLUSTIONS
The AMI evaluation has been applied to the adaptation and placement of approximately 100 clients. Both actual results of placements and studies to verify the AMI have indicated that it is, in fact, a useful tool for that which it was designed. An example of one of the studies involved the ranking of the expected
efficiency of ten clients based upon the motion order analysis of a one-handed box folding operation. When the ten clients were actually assigned the task, eight of the ten predicted ranks were correct. The two in error were not significantly misranked.
AMI results were the sole basis for handicapped employee placement and adaptation for a production line producing license tags for the State of Kansas. This production line involved ten severely physically disabled employees. The minimum production rate acceptable exceeded 1500 units per day. All placements and adaptations were successful with the exception of one individual due to emotional rather than physical problems.
62 R. D. DRYDEN ET AL.