Ergonomic scissors for hairdressing

International Journal of Industrial Ergonomics 32 (2003) 199–207

Ergonomic scissors for hairdressing

Jason L. Boylesa, Robert D. Yearouta, Malgorzata J. Rysb,*aDepartment of Management and Accountancy, University of North Carolina at Asheville, One University Heights,

Asheville, NC 28804, USAbDepartment of Industrial and Manufacturing Systems Engineering, Kansas State University, Durland Hall,

Manhattan, KS 66506-5101, USA

Received 12 November 2002; received in revised form 26 November 2002; accepted 17 March 2003

Abstract

For decades, hairstyles have been plagued with repetitive motion injuries (RMI). To alleviate RMI symptoms and

improve body mechanics, Chiavaras and Neimken designed a hairdressing scissors that incorporates some of the

characteristics of an ergonomically designed tool. The scissors, which were patented by the United States Patent Office

and titled Ergonomic Tool Design (ETD) Scissors, were evaluated to determine if there were significant differences

between this design and the standard scissors for hairstylist’s preference and potential pain and risk reduction. Forty-

four volunteer subjects were used. Since data were heterogeneous, Satterwaite’s statistical approximation was applied

(a ¼ 0:05). Subjects preferred the ETD scissors to the traditional scissors and reported less shoulder and wrist pain.

Subjects who used the ETD scissors had significantly higher grip strength than when they used the traditional scissors.

Subjects also reported significantly less bending in the wrist when using the ETD scissors. The ETD scissors allowed for

the preferred hair growth cut to be completed with ease.

Relevance to industry

Scissors are an essential hand tool for any hairstylist. Standard scissors are straight or have only a slight curve in their

design and require the hairstylist to continually bend the wrist or contort the body. The repetitive use of the fingers and

forearms of any scissors operation places a great deal of stress on the tendons that run through carpal tunnel. Since

traditional scissors rarely allow the hand to be in the neutral position, this bent posture aggravates the already stressed

tendons placing the operator at risk for injury. The ETD scissors significantly reduce the time the wrist is bent.

Conversely, they increase the time the wrist is in the neutral position. Thus, hairstylist who uses these scissors for long

periods should experience reduced risk of occurring RMI and CTS symptoms.

r 2003 Elsevier Science B.V. All rights reserved.

Keywords: Tool Design; Scissors; CTS; Grip strength; Wrist/hand pain

1. Introduction and problem

Ergonomics is an evolving, inexact science,which aims, in part, to reduce cumulative trauma

disorders (CTD) by ensuring that jobs, work tasks,workstations, tools and equipment are designedwithin each worker’s physical capabilities andlimitations (LaBar, 1992). Ergonomics is alsoknown for the role it plays in reducing inefficien-cies by systematically searching for ways to reduceerror. Ignoring continuous error and/or physical

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*Corresponding author. Tel.: +1-785-532-3733.

E-mail address: [email protected] (M.J. Rys).

0169-8141/03/$ - see front matter r 2003 Elsevier Science B.V. All rights reserved.

doi:10.1016/S0169-8141(03)00064-7

stress can cause trauma disorders such as repetitivemotion injuries (RMI). A common RMI symptomreported today is carpal tunnel syndrome (CTS).CTS also has been labeled occupational overusesyndrome or repetitive strain (Konz and Johnson,2000). While these conditions have always beenwith the workforce, it was not until the past 20years that the effects of computer keyboards andtheir repetitive actions from key stroking caused amajor concern about CTS. CTS is caused bycompression of the median nerve, which passesthrough the carpal tunnel in the wrists (Jacksonet al., 1995). This compression occurs when thesize of the tunnel is reduced by wrist deviation ofthe finger flexor tendons, which also pass throughthis area (Storti, 1990). Symptoms include pain,numbness, tingling, clumsiness and lack of sweat-ing in parts of the hand innervated by the mediannerve. These symptoms may be felt spontaneouslyrather than constantly, with the majority of severesymptoms experienced during the night (Storti,1990). Although both genders are susceptible toCTS, smaller wrist dimensions, increased retentionof body fluids, menstrual cycles, pregnancy, andbreast-feeding contribute to an increased suscept-ibility among women (Konz, 1990). If left un-treated, CTS can result in partial or completedisability of the hand (Greer et al., 1992).

Storti (1990) reported that bending the wristforward 90� (acute volar flexion) resulted in asignificant increase in pressure in the median nervein the wrist. The preponderance of evidencesupports recommendations for workers to keeptheir wrists straight (neutral position) while rotat-ing the forearm and hand. This led Konz andMital (1990) to suggest guidelines for preventingand alleviating the symptoms associated with CTSin the design of hand tools. Four broad categorieswere listed as follows: frequency (reduce thenumber of cycles for a specific wrist), joint angle(keep the wrist in the neutral position), force(reduce the amount of force and its duration) andnon-ergonomic (medical).

Scissors are an essential hand tool for anyhairstylist. Standard scissors are straight or haveonly a slight curve in their design. These scissorsput a great deal of stress on the carpal tunnelbecause of the repetitive use of the fingers and

forearms. Traditional scissors rarely place thehand in its neutral position. The tendency forscissors used by hairstylists to have straighthandles may be due to traditional or ease ofmanufacturing, but nevertheless they are straight(Konz and Streets, 1984). Recently, a handsurgeon (Chiavaras and Neimken, 2000) statedthat in treating hairstylists who have been practi-cing for 5–10 years, almost all of them came incomplaining of pain or numbness in the upperextremity of the hand, wrist, and shoulder. Inaddition to the normal risk factors associated withCTS, most hairdressers are women. Given thisdemographic attribute, standard scissors design isa contributor to increased exposure to RMI.

To alleviate pain in his shoulder, lower back,wrist, and to improve the mechanics of cuttinghair, Chuck Chiavaras of Chiavaras Hair Design,in cooperation with hand surgeon Ronald Neim-ken of Carolina Hand Surgery Associates, Inc.,designed and patented a pair of ETD hairstylistscissors (Chiavaras, 2001). These unique scissorswere designed with a bend in the handles of 90�

(Fig. 1) to ensure an ergonomic advantage byattempting to keep the hand in the neutral(handshake) position (Figs. 2–4) while cutting hairfrom any angle. The purpose of the bend is for thescissors to fit the job process. Standard scissorscontinually take the hand out of the neutralposition and torque the rest of the body from thehips to the shoulders (Figs. 2–4). The intent of theprototype was to adhere to the basic guidelines forhand tool design. Particular attention was paid

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Fig. 1. ETD scissors. Note that the fingers are parallel to the

scissors blades instead of perpendicular.

J.L. Boyles et al. / International Journal of Industrial Ergonomics 32 (2003) 199–207200

especially to guidelines #1: ‘use of special-purpose

tools’, #2: ‘design tools to be used by either hand’,and #7: ‘consider the angles of the forearm, grip and

tool’. In other words put the ‘‘bend in the tool and

not in the wrist’’ (Konz and Johnson, 2000).The intent of the design was to allow the

hairstylist’s wrists to remain in the neutral positionand the arm to remain below the shoulder. Note inFigs. 2–4 that the wrist in the right frame(standard scissors) is bent at almost a 90� where

in the left frame (ETD scissors) the wrist is in theneutral position.

A pilot study, with 8 subjects, determined thatthe ETD scissors had the potential to alleviate orrelieve RMI symptoms, reduce CTS disease, aswell as reduce back pain and fatigue (Boyles et al.,2001). During analysis, the data collection ques-tionnaire was determined to contain sufficientvalidity and reliability for an expanded study.Subjects used in the pilot study were disqualifiedfor participation in the study discussed in thispaper. The purpose of this study was to expand thepilot study with sufficient subjects in order tomake statistically significant inferences to thebenefits of the ETD scissors where appropriate.

A hairdresser will work either for himself orherself or for a salon owner. When working for thesalon owner, they generally rent their cubical andequipment with the exception of scissors. Qualityof performance is measured in customer satisfac-tion that is rewarded by gratuities, return appoint-ments, or both. A quality hairdresser’sappointment schedule will be full 4–5 weeks inadvance. Thus, how many and the quality ofhaircuts is not a relevant performance criteria.What is of concern for the operator is painmanagement and customer satisfaction.

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Fig. 2. ETD scissors (left) versus standard (right) view 1. Note:

Position of the elbow is above the shoulder and the wrist is bent

at a 90� angle when using the standard scissors.

Fig. 3. ETD scissors (left) versus standard (right) view 2. Note:

Position of the wrist that is bent backwards in an unnatural

position when using the standard scissors.

Fig. 4. ETD SCISSORS (left) versus standard (right) view 3.

Note: The wrist in the right frame (standard scissors) is bent at a

90� angle while in the left frame (ETD scissors) the wrist is in

the neutral position.

J.L. Boyles et al. / International Journal of Industrial Ergonomics 32 (2003) 199–207 201

2. Method

2.1. Data collection instrument

To insure that the subject used the scissorscorrectly, the investigator observed the co-inventorusing his ETD scissors. Both the standard andETD scissors were demonstrated as illustrated inFigs. 2–4. Various cutting techniques as well asposition with the body, shoulders, arms, wrist, andfingers were observed. From these observations acomfort ballot, using standard scales, was devel-oped to collect data for both scissors. A standardsubject briefing statement was then prepared toreduce potential investigator bias. This statementinformed the subjects that the study would be fortwo 8-h days and that they would use both thestandard and the ETD scissors. Subjects were alsoinformed that they would fill out a comfort ballotat the end of each 8-h day.

2.2. Subjects

Forty-four volunteer subjects, hairstylists, fromCentral Kansas, Central North Carolina andWestern North Carolina participated in 2-daystudy. Each subject was given the standard briefingand was assigned a random number that deter-mined which scissors would be used on day 1 andwhich would be used on day 2. Each treatmentbegan with collecting the subjects grip strength.

Sixteen subjects were obtained from WesternNorth Carolina, 14 were obtained in CentralNorth Carolina, and the remaining 14 came fromCentral Kansas. Forty-one subjects were femaleand 3 were male, one had been diagnosed withCTS, and all subjects passed the Phalan’s test,which is a simple diagnostic test that can revealpotential signs and symptoms of CTS. It must benoted that the subject who had been diagnosedwith CTS passed the Phalan’s test. Forty-three ofthe subjects were right-hand dominant while onewas left-hand dominant. All subjects (except two)could be classified as average weight and buildbased on standards found in Konz and Johnson(2000). The two subjects were overweight orappeared to be retaining excessive fluids. Otherdemographic data is displayed in Table 1.

2.3. Experimental design and analysis techniques

The experimental design was a classic 2n factorialdesign. Subjects performed the task of cutting hairwith the ETD scissors for one workday of 8 h andwith the standard scissors for the other day. Thesubject was assigned the ETD or standard scissorsfor the day 1 or day 2 treatment based on randomnumber selection. Grip strength was determined bytaking three grip strength samples before and aftereach day’s treatment using a Jarmar hydraulic handdynamometer. A questionnaire related to theassessment of the perceived pain was given to eachsubject at the end of each working day (seeAppendix A). Because of the small sample sizeand the large variation in some of the subject’sresponses, the authors followed the Messy Dataprocedures specified by Milliken and Johnson(1984). To determine if a comparison was statisti-cally significantly different, the significance level(alpha) of 0.05 was used for all statistical tests. Alldata were subjected to the Levine’s test forhomogeneity of variances (Milliken and Johnson,1984; Yearout et al., 1999). This test determinedthat the data were heterogeneous and wouldtherefore require either non-parametric analysis ortechniques that do assume homogeneity (Millikenand Johnson, 1984). Yearout et al. (1999) outlinedthe appropriate analysis technique for thiscondition (Satterwaite’s approximation). Since thetechnique is sufficiently robust to handle bothheterogeneous data with unequal sample sizes, itis also appropriate for all comparisons addressed inthis paper (Milliken and Johnson, 1984).

3. Results

The data collection instrument provided thesubjects the opportunity to respond to open-ended

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Table 1

Subject’s description

Variable Mean Std. dev.

Wrist circumference (cm) 15.75 1.28

Height (cm) 164.84 9.62

Weight (kg) 63.17 15.05

Hairstylist experience (years) 7.09 12.06


questions. The major responses were that the ETDscissors allowed the body to be in a morecomfortable position, allowed for a straightercut, and allowed the hairstylists to cut in the samedirection without bending the wrist. The onesubject diagnosed with CTS stated that the ETDscissors helped with her pain symptoms. Forquality purposes, hairstylists prefer to make a cutin the direction which the hair grows/flows.Subjects stated that the ETD scissors allowed forthe preferred hair growth cut to be completed withease, whereas the standard scissors did not. Asshown in Fig. 5, 46% stated that they wouldpurchase the ETD scissors if it were available at areasonable price. Thirty-six percent respondedwith a maybe and 18% said that they would notpurchase the scissors, as shown in Fig. 5. Althoughthe subjects stated that the initial use of the ETDscissors was awkward, most felt that the time tofeel comfortable using the scissors was very short.

Table 2 depicts the grip strength data. Table 2and Fig. 6 show that the grip strength deterioratedby 4.88 kg by the end of the day for the standardscissors; the decrease is significant (po0:05). Whenusing the ETD scissors, the decrease of 0.39 kg wasnot statistically significant.

Perceived pain was important to data collectionand was done for both the standard and ETDscissors. Perceived pain was based on a semantic-differential scale with ratings from 1 to 7 (seeAppendix A). The scale’s range allowed subjects torecord perceived pain scale from no discomfort tosevere discomfort. Since the questions were similar

in nature, similar questions were pooled in orderto calculate the mean rating and standard devia-tion for analysis for significant difference. Table 3,Figs. 7 and 8 depict results that focused onperceived pain in the hand, wrist, back andshoulders.

Pain was significantly less (po0:05) for backand shoulders and significantly less (po0:05) forhand/wrist.

Percentages for when the wrist was bent andwhen either hand was above the shoulder arereported in Table 4, Figs. 11 and 12 (refer toAppendix A for questions asked).

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Fig. 5. Choice of purchasing the ETD scissors.

Table 2

Grip strength data (N ¼ 44)

Type scissors/treatment Mean (kg) Std. dev.

Standard

Before work 33.7 10.6

After work 28.9 10.3

ETD

Before work 34.6 10.1

After work 34.3 8.8

Fig. 6. Grip strength before and after 8-h treatment.


Figs. 9 and 10 show the regions on the handwith the counts where pain or tiredness was feltafter the use of the scissors for both the standardand the ETD scissors. The counts for the painregions are shown in the specific regions on thehand where space permits and to the left of theregion otherwise. For the STD scissors, there is atotal of 45 pain counts while for the ETD thenumber is only 10. Thus, subjects using thestandard scissors experienced pain in more regionsof the hand and the number of subjects reporting

pain was also higher with the STD scissors. Thesubjects reporting pain in the hand after the use ofthe ETD scissors were fewer in number and theregions experiencing pain on the hand alsodiminished.

To insure reliability and validity of the subject’sresponses to queries concerning wrist and armposture the results from complementary questions1 and 2 were compared. By normalizing theperceptual responses for when the wrist was inthe neutral position versus when the wrist was bentand making a comparison for both neutral andbent positions, there were no statistically signifi-cant differences (po0:05). Thus, the data collec-tion instrument’s reliability and validity wasconfirmed.

Table 4 and Fig. 11 show the wrist postureeffect. The hand was bent significantly less(po0:05) for the ETD scissors (mean=19.9%)than for the conventional scissors (mean=63.7%).

Table 4 and Fig. 12 show the shoulder/backeffect. The percent of time the hand was above theshoulder was 27% for the ETD scissors and 53.2%for the conventional scissors; the difference issignificant (po0:05).

Table 4 and Fig. 13 show the wrist bent whencutting a straight line. The percentage of the time

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Table 3

Perceived pain on a 1–7 (no discomfort–severe discomfort) scale

Body location Mean rating (1–7) Std. dev.

Hand and wrist

Standard scissors 2.1 1.4

ETD scissors 1.3 0.7

Back and shoulders



Fig. 7. Perceived pain (wrist/hand).

Fig. 8. Perceived pain (back and shoulders).

Table 4

Percent that the wrist is bent or the hand is above the shoulders

Body location Mean rating

(percent of total

time)

Std.

dev.

Hand is neutral



Hand is bent



Hand above the shoulders


ETD Scissors 17.2 18.2

Wrist bent when cutting a

straight line




the wrist was bent for the ETD scissors was 10.5%as compared to 62.8% for the conventionalscissors; the difference is significant (po0:05).These statistical results reinforce the subjects large

number of open-ended comments that the EDTscissors allowed for cutting a straight line withmuch greater ease and less body contortion.

4. Discussion

This study demonstrates that the ETD scissorsreduce bending of the wrist, thus permitting thewrist and hand to remain in the neutral (hand-shake) position. There was statistically significant

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Fig. 10. Number of subjects (out of the 41) experiencing pain in

specified regions after using the ergonomic scissors.

Fig. 9. Number of subjects (out of the 41) experiencing pain in

specified regions after using the standard scissors.

Fig. 11. Percent of time the wrist was bent.

Fig. 12. Percentage of the time hand was above shoulders.

Fig. 13. Percent of the time the wrist was bent when cutting a

straight line.


reduction for grip strength when using thestandard versus the ETD scissors at the end ofan 8-h workday. Thus the ETD scissors retard gripstrength deterioration. There was a significantreduction of perceived pain in the hands, back,and shoulders. There were significant differences inthe amount of time or occurrences that the handand wrist were above the shoulders. Thus, usingthe ETD scissors will significantly reduce theamount of time that the hairstylist will be requiredto lift his or her hand and wrist above theshoulders while cutting hair. In reviewing thesubjects’ comments, there was a consensus thatthe ETD scissors are an improvement. The majorcomment was that the ETD scissors allow thestylist to cut a straight line with less difficulty.The ETD scissors also allow the stylist to cut withthe flow of the hair without contorting their wristand upper body posture. Of the hairstylists, 46%stated that they would purchase the scissors,indicating that there were sufficient benefits towarrant exchanging their current scissors for theETD scissors.

5. Conclusion

This study’s results demonstrate that the ETDscissors are an effective tool in reducing perceivedpain, deterioration in grip strength, bending thewrist, and reducing the requirement for the handand wrist to be above the shoulder, therebysignificantly reducing the risk of CTS and RMIsymptoms. The authors also recommended thatthe ETD scissors be packaged with soft plasticinserts to allow for better operator fit and to assistin relieving soft-tissue pressure. The inventorsshould consider modifying their patent in orderto gain more universal customer acceptance andextend the life of the current patent.

Acknowledgements

The authors wish to express their appreciationto Dr. Ronald Neiemkin of Duke University andCarolina Hand Surgeons, Associates and Mr.Chuck Chiavaras of Chiavaras Hair Design for

the use of their ETD scissors and encouragementin this project, The Crum’s Beauty College andNisha Nair, a graduate student in the Departmentof Industrial and Manufacturing Systems Engi-neering at Kansas State University for their help inthe data-gathering process.

Appendix A

Please mark on the scale below the question howaccurately the scale’s descriptors indicate anydiscomfort you may feel at the end of the day.

7. Are you experiencing any pain in yourshoulder or neck?

1 2 3 4 5 6 7+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -+no slight moderate severe

8. Are you experiencing any pain in yourhips?


9. Are you experiencing any pain in yourlower back?


Below are questions relating to your perceptionsof the use of scissors during the weekday. Ratehow accurately these describe how you feel usingthe following scale:

1. How often was your hand in the neutralposition (hand shake position) during haircutting?

0 10 20 30 40 50 60 70 80 90 100+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -+

2. How often did you have to bend your wristwhile cutting hair?

0 10 20 30 40 50 60 70 80 90 100+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -+

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3. How often do you have to raise your armsabove your shoulders to cut hair?

0 10 20 30 40 50 60 70 80 90 100+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -+

4. How often was the wrist you attempted to cuta straight line?

0 10 20 30 40 50 60 70 80 90 100+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -+

In your own words describe how this pair ofscissors helped or did not help in cutting a straightline.

Would you purchase the scissors that you usedfor this test?

Please record any other comments that you mayhave?

References

Boyles, J., Yearout, R., Rys, M., Neimken, R., 2001.

Effectiveness of the Ergonomic Tool Design (ETD) Scissors

(Pilot Study). Advances in Occupational Ergonomics and

Safety. IOS Press, Amsterdam, pp. 218–224.

Chiavaras, C., 2001. High-tech scissors have a healthful bent

salon today: for finer salons only. Lincolnshire 18 (2), 38.

Chiavaras, C., Neimken, R., 2000. Ergonomic tool design:

home of the revolutionary ETD scissors for hairstylists.

Hyperlink ‘‘http://www.haircut2001.com.

Greer, B., Jenkins, W., Roberts, R., 1992. Carpal tunnel

syndrome: a challenge for rehabilitation. Journal of

Rehabilitation 58, 43–46.

Jackson, J., Kelly, B., Taylor, J., Yearout, R., 1995. Carpal

tunnel syndrome: case study of an intercollegiate

athlete. International Journal of Industrial Ergonomics 15,

297–300.

Konz, S., Johnson, S., 2000. Work Design: Industrial Ergo-

nomics. Holcomb Hathaway Publishers, Scottdale, AZ.

Konz, S., Mital, A., 1990. Guidelines: carpal tunnel syndrome.

International Journal of Industrial Ergonomics 5, 175–180.

Konz, S., Streets, B., 1984. Bent hammer handles: performance

and preference. Kansas State University Experiment Re-

search Report, No V, Manhattan, KS 66506, V-B-1-3.

LaBar, G., 1992. Succeeding with ergonomics. Occupational

Hazards (OHA) 54 (4), 29–33.

Milliken, G., Johnson, D., 1984. . Analysis of Messy Data,

Designed Experiments, Vol. 1. Lifetime Learning, London.

Storti, P.A., 1990. Getting a grasp on carpal tunnel syndrome.

Risk Management 37, 40–48.

Yearout, R., Barger, R., Yates, G., Linserski, D., 1999. A

methodology for appropriate testing when data are hetero-

geneous. International Journal of Industrial Ergonomics,

Elsevier, Amsterdam, 1999, pp. 129–134.

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http://www.haircut2001.com

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Ergonomic scissors for hairdressing