1 Effects of different kinds of arch support materials for prolonged standing Reporter : Chao-Yi Zheng Adviser : Sai-wei Yang Date: 2007/06/06

2 Guideline Introduction Introduction Motivation and purpose Motivation and purpose Material and method Material and method Flow chart Flow chart references references

3 introduction Many occupations, such as assembly workers, require standing in one area for long periods of time. Service trade workers in Taiwan had increased 54,000 since 1999 to Standing time  7.5 time, walking time  3 time

4 fatigue and body discomfort Interference with the venous return from the lower limbs to the heart, resulting in tissue hypoxia Interference with the venous return from the lower limbs to the heart, resulting in tissue hypoxia Interference with the venous return from the lower limbs to the heart, resulting in oedema Interference with the venous return from the lower limbs to the heart, resulting in oedema Intervertebral disc stress from excessive lordosis Intervertebral disc stress from excessive lordosis Stretching of ligaments Stretching of ligaments Messing K, Kilbom A, Appl Ergon(2001)

5 Shoe insoles Shoe insoles are effective by decreasing subjective pain and discomfort felt by the worker in his natural work setting. Shoe insoles are effective by decreasing subjective pain and discomfort felt by the worker in his natural work setting. Shoe insoles are made from viscoelastic material have the best long-term ability to maintain a cushioning property. Shoe insoles are made from viscoelastic material have the best long-term ability to maintain a cushioning property. (Pratt, 1990) (Pratt, 1990)

6 the arch support can reduce muscle fatigue in the calf and disperse arch pressure Chiu and Wang, Appl Ergon(2007) The insole with maximal support to the foot have effect in decreasing low back pain. S.Shabat et al, Eur Spine J(2005) The best shoe parameter combination consists in the EVA insole hardness is 36.8 Hsieh and Wu, 1998 The best shoe parameter combination consists in the EVA insole hardness is 36.8 Hsieh and Wu, 1998

7 motivation Insole with arch support can decrease fatigue and body discomfort, but the best property for arch material is not clear. Insole with arch support can decrease fatigue and body discomfort, but the best property for arch material is not clear.

8 purpose Compare the effects of cork arch insole, EVA arch insole, and rubber arch insole on prolonged standing workers’ perceptions of discomfort and fatigue, posture stability, objective muscle fatigue Compare the effects of cork arch insole, EVA arch insole, and rubber arch insole on prolonged standing workers’ perceptions of discomfort and fatigue, posture stability, objective muscle fatigue

9 Material and method Subject s Subject s Experimental conditions Experimental conditions questionnaire questionnaire Instruments Instruments procedure procedure

10 subjects 30 semiconductor workers 30 semiconductor workers Inclusion criteria Inclusion criteria Standing more than 4 hours in the work Standing more than 4 hours in the work With no history of lower-extremity or back problems With no history of lower-extremity or back problems

11 Experimental condition Insole with arch made of cork Insole with arch made of cork insole with arch made of EVA insole with arch made of EVA insole with arch made of rubber insole with arch made of rubber Shoe: workers they wore originally shoes Shoe: workers they wore originally shoes

12 instruments objective EMG( anterior tibialis m., gastrocnemius m., erector spinae m.) EMG( anterior tibialis m., gastrocnemius m., erector spinae m.) Rs scan (COP of tandom gait with eye close) Rs scan (COP of tandom gait with eye close)Subjective questionnaire questionnaire

13 EMG anterior tibialis m., gastrocnemius m., erector spinae m. anterior tibialis m., gastrocnemius m., erector spinae m. 75% maximum voluntary contraction  keep 5 sec 75% maximum voluntary contraction  keep 5 sec Record EMG signal in 75% maximum voluntary contraction Record EMG signal in 75% maximum voluntary contraction Kim J Y, Stuart-Buttle C, and Marras W S., Appl Ergon(1994)

14 questionnaire General fatigue General fatigue Leg fatigue Leg fatigue Upper-back discomfort Upper-back discomfort Lower-back discomfort Lower-back discomfort Knee discomfort Knee discomfort Lower-leg discomfort Lower-leg discomfort Ankle discomfort Ankle discomfort Foot discomfort Foot discomfort King PM. Appl Ergon(2002)

15 Basic data collection Before work data collection After work Data collection Cork arch EVA arch rubber arch Statistics analysis Work conditions

16 procedure Before work After work questionnairequestionnaire EMGEMG COPCOP

17 Three standing conditions, each condition for a week Three standing conditions, each condition for a week Take experiments on Monday, Wednesday, and Friday before and after work Take experiments on Monday, Wednesday, and Friday before and after work

18 references Kim J Y, Stuart-Buttle C, and Marras W S. The effects of mats on back and leg fatigue. Applied Ergonomics 1994, 25(1) Kim J Y, Stuart-Buttle C, and Marras W S. The effects of mats on back and leg fatigue. Applied Ergonomics 1994, 25(1) King PM. A comparison of the effects of floor mats and shoe in-soles on standing fatigue. Applied Ergonomics 2002 Sep;33(5): King PM. A comparison of the effects of floor mats and shoe in-soles on standing fatigue. Applied Ergonomics 2002 Sep;33(5): Zander JE, King PM, Ezenwa BN. Influence of flooring conditions on lower leg volume following prolonged standing. International Journal of Industrial Ergonomics 34(2004) Zander JE, King PM, Ezenwa BN. Influence of flooring conditions on lower leg volume following prolonged standing. International Journal of Industrial Ergonomics 34(2004) Messing K, Kilbom A. Standing and very slow walking: foot pain-pressure threshold subjective pain experience and work activity. Applied Ergonomics 32(2001), Messing K, Kilbom A. Standing and very slow walking: foot pain-pressure threshold subjective pain experience and work activity. Applied Ergonomics 32(2001), Cham R. and Redfern M.S. Effect of Flooring on Standing Comfort and Fatigue. Human Factor 43(3), Cham R. and Redfern M.S. Effect of Flooring on Standing Comfort and Fatigue. Human Factor 43(3),

19 Thank you for your attention