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Richard Wells 1,2 (1) Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada (2) Centre of Research Expertise for the Prevention of Musculoskeletal.

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Presentation on theme: "Richard Wells 1,2 (1) Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada (2) Centre of Research Expertise for the Prevention of Musculoskeletal."— Presentation transcript:

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2 Richard Wells 1,2 (1) Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada (2) Centre of Research Expertise for the Prevention of Musculoskeletal Disorders (CRE-MSD)

3 1.Understand the characteristics of gloves that increase fatigue and decrease prehensile performance 2.Apply these ideas to evaluate anti- vibration gloves 3.Apply these ideas to evaluate surgical gloves

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5  Glove is stiff  Glove reduces tactility  Glove changes effective size of hand  BUT how to determine which of these factors is important  The approach is to separate out these factors using multiple measures

6 Independent variable: hand covering  Gloves – specific glove used by power line maintainers made of the same material and shape and available in different sizes which only differed in thickness  Interdigital spacers – to mimic the spacing between fingers caused by the glove thickness between the digits

7  Grip Force – grip dynamometer  Tactile Sensitivity – Von Frey hair test  Perceived Exertion – self report exertion on a 100-point rating scale  Surface EMG of seven forearm muscles.  flexor digitorum superficialis(FDS)  flexor pollicis longus (FPL)  flexor carpi radialis (FCR)  flexor carpi ulnaris (FCU)  extensor carpi radialis (ECR(B))  extensor carpi ulnaris (ECU)  extensor digitorum (ED)

8 Protocol/Participants  10 male and 10 female university students who were free of upper extremity injury or pain  Order randomized to control for any fatigue or learning effects

9  Maximum Effort – ramping effort up to maximum and hold for 3 sec  Form a grip posture – used to estimate effort required to form the hand into power grip posture  Grip foam cylinder without causing foam to visibly compress  Maintain a fixed force – maintain 75-N grip force on the dynamometer for 5 sec using visual feedback via an oscilloscope

10  Lift an object – grip the vertical arms of the dynamometer in a power grip and elevate without any horizontal movement to an approximate height of 20 mm  Grip size – dynamometer grip span was adjusted such that the thumb and tip of index finger lightly touched each other in a bare-handed relaxed grip

11 1.Increasing glove thickness and finger spacing reduces maximum grip force

12 Thicker gloves increased grip force for a constant lifting task (safety margin?)

13  Increases in glove thickness increased perceived exertion during performance of a constant submaximal grip force  Increases in glove thickness increased perceived exertion to create an unloaded grip posture

14  Increases in glove thickness increased forearm muscle activation during performance of a constant submaximal grip force  Increases in glove thickness increased forearm muscle activation to create an unloaded grip posture

15  Increases in glove thickness increased forearm muscle activation during performance of a constant submaximal grip force  Increases in glove thickness increased forearm muscle activation to create an unloaded grip posture

16  Increased glove thickness reduced tactile sensitivity

17  Increasing glove thickness made it impossible for the fingers to reach around and touch the thumb as in the bare hand condition  Adjusting the grip span to compensate for the effective increase of grip span incurred by wearing thick gloves decreased grip force output

18 b This load is present in all situations

19 Tactility on palmar surface Fit at fingertips Thickness between fingers Stiffness/ Resistance to bending Friction/texture on palmar surface Friction inside glove Fit Overall

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21  Style:  Finger vs Fingerless  Vibration Dampening:  Air Bladder vs Sorbothane + Match glove to tool frequency  Age of glove:  Decrement in performance with age  Quality:  Adherence to ISO Glove Testing Standard  Trade-offs Vibration dampening material thickness Reduced tactility Increased grip force Increased vibration transmission VIBRATION Increased efforts to use glove HAND

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23 Protection Cuts Punctures  Bare00  Single Latex++  Double Latex++++  Triple Latex++ ┤ ++  Orthopaedic Latex++++  Glove Liners  Woven++++  Non-woven  Indicator gloves*++++  Overgloves++++ *But more cuts/punctures found during surgery

24 Dexterity  Latex gloves are recommended when manual dexterity and tactility are particularly important.  Neoprene and nitrile gloves typically have a lower elasticity and are less comfortable than latex Latex Allergy Options  Low-allergen gloves (but amount of latex is not usually stated on packaging),  Non-powdered gloves, as the cornstarch power in powdered gloves is an efficient allergen carrier.  Non-latex gloves, nitrile, vinyl, polyisoprene, vinyl(PVC) and neoprene.  BUT, latex gloves are more flexible and reseal more readily after minor punctures. Latex Neoprene Nitrile

25 1.Understand characteristics of gloves in general that increase fatigue and decrease prehensile performance 2.Use these ideas to evaluate anti-vibration gloves 3.Use these ideas to evaluate surgical gloves

26  Heather Carnahan  Kirsten Willms  Patricia Rosati  Kevin Hurley  EUSA  Shannon Hunt (nee Maracle)  Carrie Boyle  Workplace Safety and Insurance Board

27  Willms, K*., Wells, R., and Carnahan, H. Determinants of force decrement in gloved power grip, Human Factors, 51: ,  Wells, R., Hunt, S. Hurley, K., Rosati, P. (2010) Laboratory assessment of the effect of heavy rubber glove thickness and sizing on effort, performance and comfort., International Journal of Industrial Ergonomics, 40:  Wells, R., Hunt, S, Rosati, P., Hurley, K. The effects of heavy electrical gloves on powerline maintainers' effort and performance: Opportunities for improvement, submitted to Applied Ergonomics  Hunt, S, Boyle, C and Wells, R. Comparison of five approaches to keeping power line maintainers’ hands warm during work in the cold, abstract for presentation at IEA2012 


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