Research in Progress: Review of
Tractor Seating Issues Related to
Ergonomics of Difference
C.S. Wilhite, University of New Mexico-School of Medicine
W.E. Field, Purdue University
Funded Research-Southwest Center for Agricultural Health, Injury
Prevention, and Education, NIOSH-2U540H007541, CFDA # 93. 262
No other financial disclosures
Introduction
• Agricultural machinery technology is rapidly evolving.
• Design of seating, seat materials, and management of
seated pressure largely unchanged.
• Current seating may not conform to the needs of
people who vary by size, weight, posture, gender, or
health status (ergonomics of difference).
• People with ergonomics of difference may have to
incorporate after-market accommodations to fit
themselves to the seating conditions.
• No research on risks/benefits of changing the dynamics
of the seating system.
Example: AgrAbility
• Farmers with spinal cord injuries (SCI)
– Access machinery with fabricated manlifts and operate
machinery with hand controls
– Paralysis create changes in sensation, motor function,
circulation, and tissue health that can pre-dispose the
person to skin tears, lacerations, and pressure-related
ulcers
– Most farmers with SCI select additional cushioning
materials (WC cushions, egg-crate foam, sheepskins, etc.)
Research
•
•
Purpose:
– Test feasibility of mapping seated
pressure on an average original
equipment foam contour tractor
seat, with and without
intervention wheelchair cushions
Subjects:
– Convenience sampling
– Inclusion: Person with SCI, no
current unstable decubitus ulcer
– 5 Male, 3 Female (age ranges 2560 years)
– The University of New MexicoHealth Sciences Center
Institutional Review Board (#13129) approved the research.
Research
• Methods
– Mixed methods, singlesubjects with repeated
measures
•
Instruments
– FSA Pressure Mapping
System by Vista Medical
– Simulation Platform
– Braden Scale pressure
ulcer risk questionnaire
– Likert Scale Seat Ratings
– Postural photographs
Results-Clinical Image Examples
Contour Foam Tractor Seat-Settle
Contour Foam Tractor SeatCompleted Perturbations
Results-Clinical Image Examples
High Profile ROHO Air Cushionsettle
High Profile ROHO Air CushionCompleted Perturbations
Results Summary
• Seven out of eight subjects demonstrated
better distribution of pressure, minimal
migration, and better immersion with the high
profile air cushion.
• One subject appeared to have acceptable
outcomes on both seating conditions.
• Further data transformation is underway.
Limitations
•
•
•
•
•
Laboratory vs. field conditions
Small sample size
Only one tractor seat, five conditions
Only seated pressures measured
Experience of investigator; not blinded to
results
Discussion
•
1. Are there practical limitations on how much front-end design can accommodate
the variances involved in ergonomics of difference (e.g. weight, gender, size,
postural asymmetries, and disability)?
•
2. What new materials, structures, contours, and dimensions can be incorporated
into front-end design to widen the variance for ergonomics of difference?
•
3. What should be the role of aftermarket and custom design solutions that “fit”
into existing front-end design? What research needs to be performed to ensure
aftermarket solutions are effective in resolving seating issues, without creating
other problems?
•
3. What body of knowledge and standardization of process needs to be developed
for recommending aftermarket accommodations for people with ergonomics of
difference?
•
4. Who needs to perform the work (i.e. designers, engineers, ergonomists,
researchers, occupational health nurses, and others)? Will the work be performed
in isolation or best performed through multi-disciplinary teams?
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Thank you!
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