Transcript the presentation

The Ergonomic Implications of Gesturing
Examining Single and Mixed Use
with Appropriate Placement
Lindsey Muse B.A., S. Camille Peres Ph.D., Adrian Garcia
University of Houston-Clear Lake
The Problem:
Research not keeping up with Technology
• Number of products with touch screen capabilities is
increasing
• Limited research available concerning the ergonomic
impacts of gesturing
▫ Existing research is almost completely based on
subjective measurements
• Designers and developers need objective measures
accompanied with subjective measures to understand
the impact of gesturing on the body to help avoid
injury
Areas of Interest for Ergonomics
(Independent Variables)
• Types of touch screen devices
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Handheld
Pad
Laptop
Desktop
• Input Styles:
▫ Single Use: Touch only
▫ Mixed Use: Touch and keyboard or mouse where it
applies
• Possible placement for each product
▫ Desk, Lap, Hand while sitting, Hand while standing
Conditions
Participants
•100 participants from within and outside of the
University of Houston-Clear Lake
▫ Outside the university
 $1oo each for participation
▫ Within the university
 One hour of participation credit for every hour in the study
•Participants will be selected so they have some
experience with at least one of the gesture input
devices
Objective Measures
• Surface EMG (SEMG)
▫ 12 electrodes placed on the upper body to measure
muscle activity during testing
 Bilateral - flexor, extensor, trapezius, deltoid, thenar
and hypothenar
 Mean and Standard deviation of RMS of SEMG
Subjective Measures
• Modified Body Discomfort Diagram
▫ 17 body parts and muscle groups for participants to
rate (primarily looking at the upper body)
• Open-ended questions
▫ Participants’ computer usage
▫ Their comfort or discomfort after each session
Goals
• Obtain objective and subjective ratings from
participants for the 4 touch screen devices
▫ Gather data with different input styles (single and mixed
use) where applicable
▫ Gather data in the different postures that apply to each
device
• Better understand the risks involved for these 4
products
• Provide valuable information to minimize risks in
current and future technologies
Appendix:Timeline
Appendix:Budget
Appendix:Data Analysis
• Primarily exploratory and descriptive analyses:
▫ ANOVA’s calculated for each dependent measure on
each device (and by environment where appropriate)
 subjective: BDD
 objective: S-EMG
▫ Summary of comments on open ended questions
Analyses-Subjective
• BDD: difference in ratings by
• device, posture, muscle, session
• free choice
• input device, posture
• free response
• most uncomfortable task, how uncomfortable were they
with the posture
• did counterbalance seem to matter with any of these?
Analyses-Objective
• SEMG:
• Mean EMG: by device, task, muscle, posture
• SD EMG: by device, task, muscle, posture
• Motion Capture
• 3 angles: shoulder abduction (?), elbow extension, torso lean (?)
• per device and posture (two prescribed postures):
• Typical worst posture
• how long until participants assume that posture
• how long they maintain the posture
• per device - free choice:
• Typical worst posture
• how long until participants assume that posture
• how long they maintain the posture