Job Analysis Techniques for Distal Upper Extremity Disorders

Abstract

Distal upper extremity (DUE) work-related musculoskeletal disorders (WMSDs) are among the most costly injuries suffered in industry today. These WMSDs are reported in both office (computer use) and manufacturing environments. Job physical exposure analysis techniques for DUE WMSDs range from simple checklists to quantitative models. A summary of literature review of biomechanical, physiological, psychophysical and epidemiological bases for job physical exposure risk factors for DUE WMSDs is provided. Several job analysis methods suitable for manufacturing environments are reviewed and discussed. A comparative analysis of Rapid Upper Limb Assessment (RULA), Threshold Limit Value for Hand Activity Level (TLV for HAL), and the Strain Index is provided along with results from validation studies and advantages and disadvantages of each method. Three examples from industries are provided to demonstrate applications of RULA, TLV for HAL, and the Strain Index. Last, issues with current job analysis methods when a worker rotates to different jobs and/or when a job consists of several tasks are discussed as well as the need for more robust models to account for these variations in physical exposure in real-world environments.

Keywords

distal upper extremity disorders risk factors job analysis methods RULA Strain Index TLV for HAL

Get full access to this article

View all access options for this article.

References

Abu-Ali

Purswell

J. L.

Schlegel

R. E.

(1996). Psychophysically determined work-cycle parameters for repetitive hand gripping. International Journal of Industrial Ergonomics, 17, 35–42.

Al-Eisawi

K. A.

Kerk

C. J.

Congleton

(1998). Wrist strength limitations to manual exertion capability. Occupational Ergonomics, 1, 107–121.

American Conference of Government Industrial Hygienists. (2001). Hand activity level. In TLVs and BEIs: Threshold limit values for chemical substances and physical agents (pp. 110–112). Cincinnati, OH: Author.

American Conference of Government Industrial Hygienists. (2005). Documentation of the TLVs^® and BEI with other worldwide occupational exposure values. Cincinnati, OH: Author.

K. N.

Askew

L. J.

Chao

E. Y.

(1986). Biomechanics and functional assessment of upper extremities. In Karwowski

(Ed.), Trends in ergonomics/human factors III (pp. 573–580). Amsterdam, Netherlands: Elsevier Science.

Andersen

J. H.

Hahr

J. P.

Frost

(2007). Risk factors for more severe regional musculoskeletal symptoms: A two-year prospective study of a general working population. Arthritis Rheum, 56, 1355–1364.

Angst

Dreup

Werie

Herren

D. B.

Simmen

B. R.

Goldhahn

(2010). Prediction of grip and key strength in 978 healthy subjects. BMC Musculoskeletal Disorders. Advance online publication. doi:10.1186/1471-2474-11.94

Armstrong

T. J.

Fine

L. J.

Goldstein

S. A.

Lifshitz

Y. R.

Silverstein

B. A.

(1987). Ergonomic considerations in hand and wrist tendonitis. Journal of Hand Surgery, 12A, 830–837.

Armstrong

T. J.

Punnett

Ketner

(1989). Subjective worker assessments of hand tools used in automotive assembly. American Industrial Hygiene Association Journal, 50, 639–645.

10.

Åstrand

Guharay

Wahren

(1968). Circulatory responses to arm exercise with different arm positions. Journal of Applied Physiology, 25, 528–532.

11.

Bao

(2004, January). Hand-intensive jobs: Effectively evaluating risk levels. Professional Safety, pp. 28–34.

12.

Bao

Howard

Spielholz

Silverstein

(2006). Quantifying repetitive hand activity for epidemiological research on musculoskeletal disorders: Part II. Comparison of different methods for measuring force level and repetitiveness. Ergonomics, 49, 381–392.

13.

Beaton

D. E.

O’ Driscoll

S. W.

Richards

R. R.

(1995). Grip strength using BTE work simulator and the Jamar Dynamometer: A comparative study. Journal of Hand Surgery, 20A, 293–298.

14.

Bernard

B. P.

(Ed.). (1997). Musculoskeletal disorders and workplace factors: A critical review of epidemiologic evidence for work related musculoskeletal disorders of the neck, upper extremity, and low back (DHHS Publication No. 97-141). Cincinnati, OH: National Institute for Occupational Safety and Health.

15.

Bjorksten

Jonsson

(1977). Endurance limit of force in long-term intermittent static contractions. Scandinavian Journal of Work, Environment & Health, 3, 23–27.

16.

Bloswick

Hall-Counts

Reeve

Joseph

B. S.

Sesek

Walton

Drinkaus

Schwartz

(2003, August). An ergonomic survey tool for industrial operations. Paper presented at the International Ergonomics Association 15th Triennial Congress, Seoul, Korea.

17.

Bonfiglioli

Mattioli

Fiorentini

Graziosi

Curti

Violante

F. S.

(2007). Relationship between repetitive work and the prevalence of carpal tunnel syndrome in part-time and full-time female supermarket cashiers: A quasi-experimental study. International Archives of Occupational and Environmental Health, 80, 248–253.

18.

Borg

G. A. V.

(1982). Psychophysical bases of perceived exertion. Medicine and Science in Sports and Exercise, 14, 377–381.

19.

Bovenzi

Della

Nataletti

Alessandrini

Poian

(2005). Work-related disorders of the upper limb in female workers using orbital sanders. International Archives of Occupational and Environmental Health, 78, 303–310.

20.

Bureau of Labor Statistics. (2009). Nonfatal occupational injuries and illnesses requiring days away from work, 2007 (USDL 08-1716). Retrieved form http://www.bls.gov/iif/oshwc/osh/case/osnr0031.pdf

21.

Byström

Fransson-Hall

(1994). Acceptability of intermittent handgrip contractions based on physiological response. Human Factors, 36, 158–171.

22.

Catovic

Kraljevic

Muftic

(1991). The influence of arm position on the pinch grip strength of female dentists in standing and sitting positions. Applied Ergonomics, 22, 163–166.

23.

Chaffin

D. B.

(1973). Localized muscle fatigue: Definition and measurement. Journal of Occupational Medicine, 15, 346–354.

24.

Chiang

Chen

(1990). The occurrence of carpal tunnel syndrome in frozen food factory employees. Kaohsiung Journal of Medical Sciences, 6, 73–80.

25.

Chiang

Chen

Chang

(1993). Prevalence of shoulder and upper-limb disorders among workers in the fish processing industry. Scandinavian Journal of Work, Environment & Health, 19, 126–131.

26.

Choobineh

Tosian

Alhamdi

Davarzanie

(2004). Ergonomic intervention in carpet mending operation. Applied Ergonomics, 35, 493–496.

27.

Ciriello

V. M.

Webster

B. S.

Dempsey

P. G.

(2002). Maximum acceptable torques of highly repetitive screw driving, ulnar deviation, and handgrip tasks for 7-hour workdays. American Industrial Hygiene Association Journal, 63, 594–604.

28.

Crosby

C. A.

Wehbe

M. A.

Mawr

(1994). Hand strength: Normative values. Journal of Hand Surgery, 19, 665–670.

29.

Dahlan

J. B.

Fernandez

J. E.

(1993). Psychophysical frequency for a gripping task. International Journal of Industrial Ergonomics, 12, 219–230.

30.

Dempsey

(1999). Utilizing criteria for assessing multiple-task manual materials handling jobs. International Journal of Industrial Ergonomics, 24, 405–416.

31.

Dempsey

P. G.

McGorry

R. W.

Maynard

W. S.

(2005). A survey of tools and methods used by certified professional ergonomists. Applied Ergonomics, 36, 489–503.

32.

Drinkaus

Sesek

Blowsick

Bernard

Walton

Brad

Reeve

Counts

J. H.

(2003). Comparison of ergonomic risk assessments outputs from Rapid Upper Limb Assessment and the Strain Index for tasks in automotive assembly plants. Work: A Journal of Prevention, Assessment and Rehabilitation, 21, 165–172.

33.

Driscoll

S. W.

Horii

Ness

Cahalan

T. D.

Richards

R. R.

(1992). The relationship between wrist position, grasp size and strength. Journal of Hand Surgery, 17A, 169–177.

34.

Ebersole

M. L.

Armstrong

T. J.

(2006). Analysis of an observational rating scale for repetition, posture, and force in selected manufacturing settings. Human Factors, 48, 487–498.

35.

Feveile

Jensen

Burr

(2002). Risk factors for neck-shoulder and wrist-hand symptoms in a 5-year follow-up study of 3,990 employees in Denmark. International Archives of Occupational and Environmental Health, 75, 243–251.

36.

Firrell

J. C.

Crain

G. M.

(1996). Which setting of the Dynamometer provides maximal grip strength? Journal of Hand Surgery, 21A, 397–401.

37.

Fountain

L. J.

(2003). Examining RULA’s postural scoring system with selected physiological and psychophysiological measures. International Journal of Occupational Safety and Ergonomics, 9, 383–392.

38.

Franzblau

Armstrong

T. J.

Werner

R. A.

Ulin

S. S.

(2005). A cross-sectional assessment of the ACGIH TLV for hand activity level. Journal of Occupational Rehabilitation, 15, 57–67.

39.

Friedman

S. L.

Palmer

A. K.

Short

W. H.

Levinsohn

E. M.

Halperin

L. S.

(1993). The change in ulnar variance with grip. Journal of Hand Surgery, 18A, 713–716.

40.

Gardner

B. T.

Dale

A. M.

VanDillen

Franzblau

Evanoff

B. A.

(2008). Predictors of upper extremity symptoms and functional impairment among workers employed for 6 months in a new job. American Journal of Industrial Medicine, 51, 932–940.

41.

Garg

Cykana

L. J.

Hegmann

K. T.

(2003, August). Effects of center of mass and wrist posture on maximum grip strength, wrist strength and grip force. Paper presented at the International Ergonomics Association 15th Triennial Congress, Seoul, Korea.

42.

Garg

Hegmann

K. T.

Kapellusch

(2006). Short-cycle overhead work and shoulder girdle muscle fatigue. International Journal of Industrial Ergonomics, 36, 581–597.

43.

Garg

Hegmann

K. T.

Schwoerer

B. J.

Kapellusch

J. M.

(2002). The effect of maximum voluntary contraction of endurance times for the shoulder girdle. International Journal of Industrial Ergonomics, 30, 103–113.

44.

Garg

Kapellusch

(2009a). Applications of biomechanics for prevention of work-related musculoskeletal disorders. Ergonomics, 52, 36–59.

45.

Garg

Kapellusch

(2009b, August). Consortium pooled data job physical exposure assessment. Paper presented at IEA 2009, Beijing, China.

46.

Garg

Kapellusch

Hegmann

K. T.

Merryweather

(2010). Upper limb musculoskeletal disorders: Quantifying risk factors (Final Report, 5U01 OH007917). Washington, DC: U.S. Department of Health and Human Services.

47.

Gell

Werner

R. A.

Franzblau

Ulin

S. S.

Armstrong

T. J.

(2005). A longitudinal study of industrial and clerical workers: Incidence of carpal tunnel syndrome and assessment of risk factors. Journal of Occupational Rehabilitation, 15, 47–55.

48.

Gunther

C. M.

Burger

Rickert

Crispin

Schulz

C. U.

(2008). Grip strength in healthy Caucasian adults: Reference values. Journal of Hand Surgery, 33, 558–565.

49.

Haahr

J. P.

Andersen

J. H.

(2003). Physical and psychosocial risk factors for lateral epicondylitis: A population based case-referent study. Occupational and Environmental Medicine, 60, 322–329.

50.

Hagberg

(1981). Workload and fatigue in repetitive arm elevations. Ergonomics, 24, 543–555.

51.

Hagberg

Silverstein

Wells

Smith

Hendrick

H. P.

Carayon

Pérusse

(Eds.). (1995). Work-related musculoskeletal disorders (WMSDs): A reference book for prevention. London, UK: Taylor and Francis.

52.

Hagg

G. M.

Milerad

(1997). Forearm extensor and flexor muscle exertion during simulated gripping work-an electromyographic study. Clinical Biomechanics, 12, 39–43.

53.

Hagg

G. M.

Oster

Bystrom

(1997). Forearm muscular load and wrist angle among automobile assembly line workers in relation to symptoms. Applied Ergonomics, 28, 41–47.

54.

Harkonnen

Piirtomaa

Alaranta

(1993). Grip strength and hand position of the dynamometer in 204 Finnish adults. Journal of Hand Surgery (British European Volume), 18B, 129–132.

55.

Herberts

Kadefors

Andersson

Petersen

(1981). Shoulder pain in industry: An epidemiological study on welders. Acta Orthopaedica Scandinavica, 52, 299–306.

56.

Herberts

Kadefors

Broman

(1980). Arm positioning in manual tasks: An electromyographic study of localized muscle fatigue. Ergonomics, 23, 655–665.

57.

Herrin

G. D.

Jaraieidi

Anderson

C. K.

(1986). Prediction of overexertion injuries using biomechanical and psychophysical models. American Industrial Hygiene Association Journal, 47, 322–330.

58.

Imrhan

S. N.

Rahman

(1995). The effects of pinch width on pinch strengths of adult males using realistic pinch-handle coupling. International Journal of Industrial Ergonomics, 16, 123–134.

59.

Jones

Kumar

(2010). Comparison of ergonomic risk assessments output in four sawmill jobs. International Journal of Occupational Safety and Ergonomics, 16, 105–111.

60.

Jørgensen

Fallentin

Krough-Lund

Jensen

(1988). Electromyography and fatigue during prolonged, low-level static contractions. European Journal of Applied Physiology, 57, 316–321.

61.

Jorgensen

Davis

Kotowski

Aedla

Dunning

(2005). Characteristics of job rotation in the Midwest US manufacturing sector. Ergonomics, 48, 1721–1733.

62.

Katz

Simmons

B. P.

(2002). Carpal tunnel syndrome. New England Journal of Medicine, 346, 1807–1812.

63.

Kilbom

Å.

Gamberale

Persson

Annwall

(1983). Physiological and psychological indices of fatigue during static contractions. European Journal of Applied Physiology, 50, 179–193.

64.

Kilroy

Dockrell

(2000). Ergonomic intervention: Its effect on working posture and musculoskeletal symptoms in female biomedical scientists. British Journal of Biomedical Science, 57, 199–206.

65.

Klein

M. G.

Fernandez

J. E.

(1997). The effects of posture, duration, and force on pinching frequency. International Journal of Industrial Ergonomics, 20, 267–275.

66.

Knox

Moore

J. S.

(2001). Predictive validity of the Strain Index in turkey processing. Journal of Occupational & Environmental Medicine, 43, 451–462.

67.

Kuorinka

Forcier

(Eds.). (1995). Work-related musculoskeletal disorders (WMSDs): A reference book for prevention. London, UK: Taylor and Francis.

68.

Kuzala

Vargo

(1992). The relationship between elbow position and grip strength. American Journal of Occupational Therapy, 46, 509–512.

69.

Lamoreaux

Hoffer

M. M.

(1995). The effect of wrist deviation on grip and pinch strength. Orthopaedics and Related Research, 314, 152–155.

70.

Latko

W. A.

Armstrong

T. J.

Foulke

J. A.

Herrin

G. G.

Raybourn

R. A.

Ulin

S. S.

(1997). Development and evaluation of an observational method for assessing repetition in hand tasks. American Industrial Hygiene Association Journal, 58, 278–285.

71.

Leclerc

Landre

M. F.

Chastang

J. F.

Niedhammer

Roquelaure

, & the Study Group on Repetitive Work. (2001). Upper-limb disorders in repetitive work. Scandinavian Journal of Work, Environment & Health, 27, 268–278.

72.

Liberty Mutual Insurance. (2009). Workplace safety index. Retrieved from http://www.libertymutual.com/researchinstitute

73.

Lind

A. R.

Taylor

S. H.

Humphreys

P. W.

Kennelly

B. M.

Donald

K. W.

(1964). The circulatory effects of sustained voluntary muscle contraction. Clinical Science, 27, 229–244.

74.

Loslever

Ranaivosoa

(1993). Biomechanical and epidemiological investigation of carpal tunnel syndrome at workplaces with high risk factors. Ergonomics, 36, 537–554.

75.

Mani

Gerr

(2000). Work-related upper extremity musculoskeletal disorders. Occupational and Environmental Medicine, 27, 845–864.

76.

Marley

R. J.

Fernandez

J. E.

(1995). Psychophysical frequency and sustained exertion at varying wrist postures for a drilling task. Ergonomics, 38, 303–325.

77.

Marras

Murgia

Pazzona

(2005). Biomechanical risk in two dairy industries with different levels of mechanization. Giornale Italiano di Medicina del Lavoro ed Ergonomia, 27, 112–118.

78.

Massaccesi

Pagnotta

Soccetti

Masali

Masiero

Greco

(2003). Investigation of work-related disorders in truck drivers using RULA method. Applied Ergonomics, 34, 303–307.

79.

Mathiassen

S. E.

(2006). Diversity and variation in biomechanical exposure: What is it, and why would we like to know? Applied Ergonomics, 37, 419–427.

80.

Mathiowetz

Kashman

Volland

Weber

Dowe

Rogers

(1985). Grip and pinch strength: Normative data for adults. Archives of Physical Medicine and Rehabilitation, 66, 69–74.

81.

McAtamney

Corlett

E. N.

(1993). RULA: A survey method for the investigation of work-related upper limb disorders. Applied Ergonomics, 24, 91–99.

82.

McCully

K. K.

Faulkner

J. A.

(1985). Injury to skeletal muscle fibers of mice following lengthening contractions. Journal of Applied Physiology, 59, 119–126.

83.

Melchior

Roquelaure

Evanoff

Chastang

J. F.

Imbernon

Goldberg

Leclerc

, & Pays de la Loire Study Group. (2006). Why are manual workers at high risk of upper limb disorders? The role of physical work factors in a random sample of workers in France (the Pays de la Loire study). Occupational and Environmental Medicine, 63, 754–761.

84.

Miranda

Heliovaara

Viikari-Juntura

(2009). Physical workload factors and carpal tunnel syndrome: A population-based study. Occupational and Environmental Medicine, 66, 368–373.

85.

Moore

J. S.

(1992a). Carpal tunnel syndrome. Occupational Medicine: State of the Art Reviews, 7, 741–764.

86.

Moore

J. S.

(1992b). Function, structure, and responses of components of the muscle-tendon unit. Occupational Medicine: State of the Art Reviews, 7, 713–740.

87.

Moore

J. S.

(2002). Biomechanical models for the pathogenesis of specific distal upper extremity disorders. American Journal of Industrial Medicine, 41, 353–369.

88.

Moore

J. S.

(2006). Applied ergonomics: Upper extremity. Training manual. Milwaukee: University of Wisconsin– Milwaukee, Center for Ergonomics.

89.

Moore

J. S.

Garg

(1994). Upper extremity disorders in a pork processing plant: Relationships between job risk factors and morbidity. American Industrial Hygiene Association Journal, 55, 703–715.

90.

Moore

J. S.

Garg

(1995). The Strain Index: A proposed method to analyze jobs for risk of distal upper extremity disorders. American Industrial Hygiene Association Journal, 56, 443–458.

91.

Moore

J. S.

Rucker

N. P.

Knox

(2001). Validity of generic risk factors and the Strain Index for predicting non-traumatic distal upper extremity morbidity. American Industrial Hygiene Association Journal, 62, 229–235.

92.

Moore

J. S.

Vos

G. A.

Stephens

J. P.

Stevens

Garg

(2006, July). The validity and reliability of the Strain Index. Paper presented at IEA 2006: 16th World Congress on Ergonomics, Maastricht, Netherlands.

93.

National Institute for Occupational Safety and Health. (1981). Work practices guide for manual lifting. Cincinnati, OH: Author.

94.

National Research Council & Institute of Medicine. (2001). Musculoskeletal disorders and the workplace: Low back and upper extremities. Panel on Musculoskeletal Disorders and the Workplace, Commission on Behavioral and Social Sciences and Education. Washington, DC: National Academy Press.

95.

Nussbaum

M. A.

Johnson

(2002). Determination and evaluation of acceptable force limits in single-digit tasks. Human Factors, 44, 545–556.

96.

Osorio

A. M.

Ames

R. G.

Jones

Castorina

Rempel

Estrin

Thompson

(1994). Carpal tunnel syndrome among grocery store workers. American Journal of Industrial Medicine, 25, 229–245.

97.

Pascual

S. A.

Naqvi

(2008). An investigation of ergonomics analysis tools used in industry in the identification of work-related musculoskeletal disorders. International Journal of Occupational Safety and Ergonomics, 14, 237–245.

98.

Potvin

J. R.

(1997). Effects of muscle kinematics on surface EMG amplitude and frequency during dynamic contractions. Journal of Applied Physiology, 82, 144–151.

99.

Rempel

Evanoff

Amadio

P. C.

de Krom

Franklin

Franzblau

Gray

Gerr

Hagberg

Hales

Katz

J. N.

Pransky

(1998). Consensus criteria for the classification of carpal tunnel syndrome in epidemiologic studies. American Journal of Public Health, 88, 1447–1451.

100.

Richards

L. G.

Olson

Palmiter-Thomas

(1996). How forearm position affects grip strength. American Journal of Occupational Therapy, 50, 133–138.

101.

Ridyard

Tapp

Wylie

(2001, January). Ergonomic job measurement system. American Society of Safety Engineers, pp. 29–31.

102.

Rodgers

S. H.

(1988). Job evaluation in worker fitness determination. Occupational Medicine: State of the Art Reviews, 3, 219–239.

103.

Rohmert

(1973). Problems in determining rest allowances: Part I. Use of modern methods to evaluate stress and strain in static muscular work. Applied Ergonomics, 4, 91–95.

104.

Roquelaure

Mariel

Dano

Fanello

Penneau-Fontbonne

(2001). Prevalence, incidence and risk factors of carpal tunnel syndrome in a large footwear factory. International Journal of Occupational and Environmental Health, 14, 357–367.

105.

Roquelaure

Mechali

Dano

Fanello

Benetti

Bureau

Mariel

Martin

Derriennic

Penneau-Fontbonne

(1997). Occupational and personal factors for carpal tunnel syndrome in industrial workers. Scandinavian Journal of Work, Environment & Health, 23, 364–369.

106.

Rucker

Moore

J. S.

(2002). Predictive validity of the Strain Index in manufacturing facilities. Applied Occupational and Environmental Hygiene, 17, 63–73.

107.

Schoenmarklin

R. W.

Marras

W. S.

Leurgans

S. E.

(1994). Industrial wrist motions and incidence of hand/wrist cumulative trauma disorders. Ergonomics, 37, 1449–1459.

108.

Seo

N. J.

Armstrong

T. J.

Ashton-Miller

J. A.

Chaffin

D. B.

(2008). Wrist strength is dependent on simultaneous power grip intensity. Ergonomics, 51, 1594–1605.

109.

Shih

(2005). Influences of span and wrist posture on peak chuck pinch strength and time needed to reach peak strength. International Journal of Industrial Ergonomics, 35, 527–536.

110.

Shivers

C. L.

Mirka

G. A.

Kaber

D. B.

(2002). Effect of grip span on lateral pinch strength. Human Factors, 44, 569–577.

111.

Silverstein

(2005). Work-related musculoskeletal disorders of the neck, back, and upper extremity in Washington State: State fund and self-insured workers compensation claims 1995-2003 (Tech. Rep. No. 40-9-2005). Olympia, WA: SHARP Program.

112.

Silverstein

Fan

Bao

Howard

Spielholz

Smith

Bonauto

Viikari-Juntura

(2006, July). How well does the Strain Index predict carpal tunnel syndrome? Paper presented at IEA 2006: 16th World Congress on Ergonomics, Maastricht, Netherlands.

113.

Silverstein

Fan

Z. J.

Bonauto

D. K.

Bao

Smith

C. K.

Howard

Viikari-Juntura

(2010). The natural course of carpal tunnel syndrome in working population. Scandinavian Journal of Work, Environment & Health. Advance online publication.

114.

Silverstein

B. A.

Fine

L. J.

Armstrong

T. J.

(1987). Occupational factors and carpal tunnel syndrome. American Journal of Industrial Medicine, 11, 343–358.

115.

Sjøgaard

Kiens

Jorgensen

Saltin

(1986). Intramuscular pressure EMG and blood flow during low-level prolonged static contraction in man. Acta Physiologica Scandinavica, 128, 475–484.

116.

Snook

S. H.

(1978). The design of manual handling tasks. Ergonomics, 21, 963–985.

117.

Snook

S. H.

Ciriello

V. M.

Webster

B. S.

(1999). Maximum acceptable forces for repetitive wrist extension with a pinch grip. International Journal of Industrial Ergonomics, 24, 579–590.

118.

Snook

S. H.

Irvine

C. H.

(1967). Maximum acceptable weight of lift. American Industrial Hygiene Association Journal, 28, 322–329.

119.

Snook

S. H.

Vaillancourt

D. R.

Ciriello

V. M.

Webster

B. S.

(1995). Psychophysical studies of repetitive wrist flexion and extension. Ergonomics, 38, 1488–1507.

120.

Snook

S. H.

Vaillancourt

D. R.

Ciriello

V. M.

Webster

B. S.

(1997). Maximum acceptable forces for repetitive ulnar deviation of the wrist. American Industrial Hygiene Association Journal, 58, 509–517.

121.

Spielholz

Bao

Howard

Silverstein

Fan

Smith

Salazar

(2008). Reliability and validity assessment of the Hand Activity Level Threshold Limit Value and Strain Index using expert ratings of mono-task jobs. Journal of Occupational and Environmental Hygiene, 5, 250–257.

122.

Statham

M. M.

Sukits

A. L.

Redfern

M. S.

Smith

L. J.

Sok

J. C.

Rosen

C. A.

(2010). Ergonomic analysis of microlaryngoscopy. Laryngoscope, 120, 297–305.

123.

Thomsen

J. F.

Hansson

G. A.

Mikkelsen

Lauritzen

(2002). Carpal tunnel syndrome in repetitive work: A follow-up study. American Journal of Industrial Medicine, 42, 344–353.

124.

Tichauer

E. R.

Gage

(1977). Ergonomic principles basic to hand tool design. American Industrial Hygiene Association Journal, 38, 622–634.

125.

Ulin

S. S.

Armstrong

T. J.

Snook

S. H.

Franzblau

(1993). Effect of tool shape and work location on perceived exertion for work on horizontal surfaces. American Industrial Hygiene Association Journal, 54, 383–391.

126.

Ulin

S. S.

Armstrong

T. J.

Snook

S. H.

Keyserling

W. M.

(1993). Perceived exertion and discomfort associated with driving screws at various work locations and at different work frequencies. Ergonomics, 36, 833–846.

127.

Ulin

S. S.

Ways

C. M.

Armstrong

T. J.

Snook

S. H.

(1990). Perceived exertion and discomfort versus work height with a pistol shaped screwdriver. American Industrial Hygiene Association Journal, 51, 588–594.

128.

U.S. Department of Labor. (2008). Occupational safety and health definitions. Retrieved from http://www.bls.gov/iif/oshdef.htm

129.

Vanswearingen

J. M.

(1983). Measuring wrist muscle strength. Journal of Orthopaedic and Sports Physical Therapy, 4, 217–228.

130.

Violante

F. S.

Armstrong

T. J.

Fiorentini

Graziosi

Venturi

Curti

Zanardi

Cooke

Bonfiglioli

Mattoli

(2007). Carpal tunnel syndrome and manual work: A longitudinal study. Journal of Occupational and Environmental Medicine, 49, 1189–1196.

131.

Washington State Department of Labor and Industries. (2000). WAC 296-62-051, Ergonomics. Retrieved from http://www.lni.wa.gov/WISHA/Rules/GeneralOccupationalHealth/PDFs/ErgoRulewithAppendices.pdf

132.

Waters

T. R.

Putz-Anderson

Garg

Fine

(1994). Applications manual for the Revised NIOSH Lifting Equation. Springfield, VA: National Technical Information Service.

133.

Werner

R. A.

Franzblau

Gell

Hartigan

A. G.

Ebersole

Armstrong

T. J.

(2005a). Incidence of carpal tunnel syndrome among automobile assembly workers and assessment of risk factors. Journal of Occupational and Environmental Medicine, 47, 1044–1050.

134.

Werner

R. A.

Franzblau

Gell

Hartigan

A. G.

Ebersole

Armstrong

T. J.

(2005b). Risk factors for visiting a medical department because of upper-extremity musculoskeletal disorders. Scandinavian Journal of Work, Environment & Health, 31, 132–137.

135.

Wurzelbacher

Burt

Crombie

Ramsey

Luo

Allee

Jin

(2010). A comparison of assessment methods of hand activity and force for use in calculating the ACGIH(R) Hand Activity Level (HAL) TLV(R). Journal of Occupational and Environmental Hygiene, 7, 407–416.