IOS Press Effects of intermittent stretching …...but no changes in the “pain impact” as...

Work 36 (2010) 27–37 27DOI 10.3233/WOR-2010-1004IOS Press

Effects of intermittent stretching exercises atwork on musculoskeletal pain associated withthe use of a personal computer and theinfluence of media on outcomes

Allen H. MarangoniDepartment of Physical Therapy, Wheeling Jesuit University, 316 Washington Ave, Wheeling, WV 26003, USATel.: +1 304 243 2372; Fax: +1 304 243 2432; E-mail: [email protected]; [email protected]

Received 31 July 2008

Accepted 7 January 2009

Abstract. Objective: The objective of this study was to evaluate the effects of regular stretching exercises on pain associatedwith working at a computer workstation, and to ascertain whether the type of media used for exercise instruction had an effect onoutcomes.Participants: Sixty-eight volunteers were divided into three equivalent groups. All of the subjects worked at computers forprolonged periods of time and reported that their pain had been a source of distress for at least three weeks prior to the intakeevaluation.Methods: A pretest-posttest-control group design with cluster randomization was used to evaluate the effect of a stretchingprogram on pain. Thirty-six different stretches were performed by the subjects for 15–17 work days. Two intervention groupswere directed to stretch once every six minutes. One group (n = 22) was reminded to stretch via a computer program, the secondgroup (n = 23) by using a hard copy version of the stretches with pictures and written instructions, and a third group received nointervention.Results: ANOVA analysis found a significant reduction in pain of 72% (p < 0.001) for the computer-generated stretchingprogram, and of 64% (p < 0.001) using the hardcopy version of the intervention. The control group had an increase in pain of1%.Conclusions: Both software and hard copy stretching interventions contributed to a decrease in pain without making any changesto workstation ergonomics and there was no significant statistical difference in the outcomes of either intervention. The subjectiveevaluation of pain using both visual analog scales and a newly created “pain spot” assessment technique yielded similar results.

Keywords: Occupational disease, carpal tunnel syndrome, muscle spasm, computer, assessment, visual analog scale, media

1. Introduction

The association between the use of personal comput-ers and symptoms of musculoskeletal disorders (MSD)has been well established in the current literature un-der a variety of names [2,7,16,25,30,38,44,47,50]. TheNational Occupational Research Agenda has identifiedpain of the upper extremities with associated preven-

tion strategies and intervention effectiveness as priorityareas [42].

The risk factors associated with MSD while work-ing at a computer include being seated, repetitive orrapid work, length of time spent at the computer, lackof support for the extremities, non-neutral body posi-tions, inactivity, lack of rest breaks, poor workstationergonomics, insufficient recovery time, static muscleloading, age, poor physical, mental or social condi-

1051-9815/10/$27.50 2010 – IOS Press and the authors. All rights reserved

28 A.H. Marangoni / Effects of stretching exercise

tions, pressure on blood vessels and nerves, pain-spasmcycles, stress on bone and connective tissues, workingwithout variety in physical movements, and others [4,17,19,28,44–46].

Specific types of ergonomic interventions were sug-gested to offset the injury attributed to the personalcomputer; however, since body types, posture, work-ing habits and personal preferences differed with eachindividual, the interventions were often found to be in-effective [13,26,29,51]. The literature addressing thecomponent parts of a computer workstation failed toidentify workstation and computer hardware as the solecause or cure of the related MSD [2,8,22,33,34].

Clerical workers and female computer operatorswere found to have the highest incidence of symptomscaused by static muscular work [6,10,14]. Electromyo-graphy (EMG) studies demonstrated that a five-minutebreak each hour decreased pain in a data entry popula-tion, that there was an association between contractedmuscles and pain, and that computer users were oftenunaware of sustained muscle contractions while seatedat their workstations. These sustained contractions of-ten extended into the rest periods and may have been thecause of vasoconstriction in the affected muscles [14,20,28,43].

At 5 and 10 percent of maximal voluntary contrac-tion (MVC) the biceps muscle was found to have aninitial decrease in oxygen concentrations that returnedto baseline after 6 minutes and demonstrated musclefatigue after 10 minutes. Other studies found that fore-arm tissue oxygenation decreased significantly duringisometric muscle contraction of as little as 5 percent ofthe MVC when held for one minute and that decreasedtissue oxygenation was associate with an increase inmuscle fatigue [12,39,40].

Software programs have been used to compare mini-breaks every 5 minutes, to mini-breaks with exerciseevery 35 minutes but did not demonstrate an effect onthe frequency and severity of complaints from com-puter users [51]. Other studies have demonstrated thatresistance and stretching exercises during the work dayyielded a decrease in subjective reports of “discomfort”but no changes in the “pain impact” as measured via avisual analog scale (VAS) [30]. Improvements in painhave been also been noted after weekends away fromwork, and muscle massage [3,43].

For those using interventions to address symptomswhile seated at a computer it may be important to knowif the type of media used to teach stretching techniquesis key to the outcomes. While the use of media is anintegral part of learning in today’s society,professionals

often give instructions to clients in a written form. Theeffects of media on learning have been argued for manyyears. One side argues that while media may improvemotivation, it is only a vehicle, while others point outthat media allows for time to learn, reduces errors andcan increase retention [5,9,15,18,27,32,41].

In summary, the specific causes of pain in those whouse computers were not evident in the literature and aremost likely multifactorial. Extended time at a computerwas associated with an increase in pain which was likelydue to decreases in tissue oxygenation, and regionalblood flow. Additionally, no protocol for successfullydecreasing the MSD associated with computer use wasfound [12,14,20,39,43].

2. Procedure

After Institutional Review Board approval was re-ceived the study began with three equivalent groupswhich were identified from a population of conve-nience. A pretest-posttest-control group design withcluster randomization was performed. Sixty-eight vol-unteers formed three equivalent groups and were em-ployed by either the university or by one of two federal-ly funded programs which were located on the campus.The university was located in the Appalachian region ofthe United States. The average age of the subjects was43 years, ranging from 21 to 62. Eighty-eight percent(60) of the participants were female. All of the subjectsworked at computers for prolonged periods of time andreported that their pain had been a source of distress forat least three weeks prior to the intake evaluation.

Thirty-six stretches lasting 10 to 15 seconds eachwere developed for this study by the researcher,a physi-cal therapist, to address areas of potential muscle spasmwhich were identified while observing subjects whowere working at computers. The stretches targetedmuscles of the neck, upper extremities, trunk, lowerextremities, eyes and breathing and were presented tothe subjects in one of two ways. In the first interventiongroup (n = 22), a Computer Assisted Stretching Pro-gram (CASP) was used. This program was developedby the author for this study to guide the subjects throughstretches using a real time audio and video display onthe computer screen. If the subject was working ona document, only the verbal instructions were heardand the video remained hidden from the screen unlesscalled up. The CASP program played one stretch ev-ery six minutes, by default, while the computer wasoperating (see Figs 1, 2 and 3). Six minutes between

A.H. Marangoni / Effects of stretching exercise 29

Fig. 1. The CASP program startup as it appeared on the video display.

Fig. 2. Selected clips of stretches used for the intervention.

stretches was selected as the interval between exercisesfor this study because it is the point at which oxygenreturns to base line in muscles being used at 5 and 10%of MVC [12] and it adds 10 mini-breaks per hour thatinterrupt static positioning associated with use of thecomputer [30,43,51].

The second version of the intervention was called theFacsimile Lesson with Instructional Pictures (FLIP).

This was a hard copy version of the CASP programand was also developed by the researcher for this study.The FLIP version incorporated selected still picturesand words transcribed from the CASP version of theprogram. These black and white pictures and text wereplaced on a spiral stand from which they could be“flipped” into place by the subject and followed thesame order as that of the CASP program. The FLIP


Fig. 3. An example of one of the stretching exercises used for both the CASP and FlIP versions of the stretching interventions.

Fig. 4. The FLIP version of the stretching program.

version used a digital kitchen timer attached to the standwhich was pre-set to alarm every six minutes once itwas activated. The timer had to be restarted after eachstretching exercise by the subject (Fig. 4). Each personwas given a journal that was tethered to the computerto record the amount of time that the intervention wasused each day. The subject was also asked to recordtheir pain level at the end of each work day and to noteif the program interfered with productivity. The thirdgroup (n = 23) comprised the non-treatment controlgroup.

Subjects were recruited via a campus wide emailasking for volunteers who were experiencing pain thatthey attributed to use of their computer. The random-ization sequence was established by listing the order ofthe date and time that the emails or phone calls werereceived by the secretary and alternating the interven-tions by assigning the CASP intervention to the firstcaller (or group if more than one subject was located in

an office cluster), the FLIP intervention to the secondcaller or group, and the control category to the nextcaller who was isolated from anyone using an interven-tion program. Recruitment of subjects was ongoing andcontinued throughout the 4 months of data collection.

Inclusion criteria were that all subjects identified thecomputer as one of the causes of pain which they hadexperienced for at least three weeks prior to the begin-ning of the study and the subject used the computer fivedays a week. Exclusion criteria were prior dislocationof an upper extremity, a health condition that may in-terfere with the study (as reported by the subject anddiscussed with the researcher) or current professionaltreatment or medication for pain. Each subject used theintervention for 15 work days unless the study comple-tion date fell on a day which was preceded by time off,in which case two days were added to negate the effectof the time away from work.

After informed consent was established, the re-searcher, a physical therapist, enrolled the participantsand conducted the intake evaluation. A picture wastaken of the subject’s workstation, a series of intakequestions regarding subjective opinions about the workenvironment and an objective ergonomic assessment ofthe computer workstation was completed. The protocolfor assessment of individual workstation risk factorswas based upon consensus of authoritative input as pub-lished in the evidence based literature (Appendix A), [1,13,16,21,24,25,28,30,31,34–37,48]. Using this evalu-ation tool, one point was deducted for each problemarea identified. For example, if the keyboard was notergonomically designed, one point would be deductedfrom the maximum score.

The next evaluation employed a standard body di-agram where the subject designated areas of pain andgraded its intensity on 10 centimeter visual analogscales (VAS) below the diagram. Subjects were askedto evaluate the pain that they felt at the end of the work-day and to mark the body image with sequential num-bers to locate its position. The sum of the numbers


Fig. 5. Pain spots with random letters varying in size from one to ten centimeters in diameter.

Fig. 6. “Pain spots” displaying pain before and after intervention.

evaluating pain on the visual analog scales were addedto give a total pain index score. For example: if pain inthe low back was rated as a 2 and pain in the neck wasrated as a 4, the pain index would be 6.

The subject was then asked to select “pain spots”to describe his or her pain. Pain Spot Assessment(PSA) was a tool developed by the researcher that usedcircles cut from thin Styrofoam sheets and varied insize using whole numbers from one to ten centimeters.They were placed in an eight by eleven inch shallowtray for selection by the subject, and were identified byrandom letters. Once the “pain spots” were selectedby the subject to represent their pain, they were tapedto the subject’s clothing in the area where pain wasindicated, a picture was taken, and their positions wererecorded. The sum of the diameters of the “pain spots”were measured in centimeters and added to determinea “pain spot” index. (Figs 5 and 6).

Pain was categorized into the following areas: cervi-cal (neck), right shoulder, left shoulder, mid-back, low-back, lower extremity, right upper extremity (but nothand or wrist), right hand or wrist, left upper extremity

(not hand or wrist pain), left hand or wrist, headache,and other pain. This data was recorded at both intakeand outtake and was analyzed as a pain index via ANO-VA and correlation analysis using SPSS. Subjects wereasked to avoid making any changes to personal exer-cise programs or to their computer workstation for theduration of the study.

Hypothesis: After using either the Computer As-sisted Stretching Program (CASP) or Facsimile Lessonwith Instructional Pictures (FLIP) as an interventionfor 15 to 17 work days, there will be a significant re-duction in the amount of pain associated with workingat a computer workstation.

3. Results

The 68 participants reported pain in the followingareas of the body upon initial evaluation, in order ofprominence: cervical (neck), right shoulder, left shoul-der, mid back, low back, lower extremities, right up-per extremity (not hand or wrist), right hand/wrist, left


Workstation, VAS and PSA evaluations and instructions for daily journaling and use of intervention

CASP Subjects N = 23 at intake,

FLIP Subjects N=24 at intake,

Control Subjects N=23 at intake,

IN

TE

RV

EN

TIO

N

Pain: 72% improvement N = 22

Pain: 64% improvement N = 23

Pain 1% worse, N=23

Self assessment of workstation and informed consent

Random Assignment to CASP, FLIP, or control group

68 Subjects complained of pain associated with computer use lasting for at least three week prior to beginning the intervention

CASP = Computer Assisted Stretching Program, FLIP = Facsimile Lesson with Instructional Pictures, VAS= visual analog scale, PSA = pain spot assessment.

Intake and final subject numbers differ due to participant attrition.

Fig. 7. CASP = Computer Assisted Stretching Program, FLIP = Facsimile Lesson with Instructional Pictures, VAS = visual analog scale, PSA= pain spot assessment. Intake and final subject numbers differ due to participant attrition.

Table 1The frequency with which pain wasreported at intake by the 68 partici-pants

Cervical (neck) = 72%,Right shoulder = 44%,Left shoulder = 40%,Mid back = 40%,Low back = 40%,Lower extremities = 13%,RUE (not hand or wrist) = 13%,Right hand/wrist = 35%,LUE (not hand or wrist) = 13%,Left hand/wrist = 20%,Headache = 14%,Other areas = 4%.

upper extremity (not hand or wrist), left hand/wrist,headache, other areas (see Table 1).

Evaluation of both the visual analog scale (VAS) andthe “pain spot” assessments (PSA) was completed usingan ANOVA analysis before the intervention, after theintervention, and to compare the differences betweenthe mean values of the initial and final results. The painindex used for comparison was the average numericalsum of all of the reported pain attributed to working ata personal computer by all of the subjects in each group(CASP, FLIP and Control). The visual analog scale was

measured to the nearest millimeter to describe the pain,while the “pain spots” were graded as whole numbersonly – one through ten centimeters.

The two intervention and one control group werefound to be equivalent when being assessed by the VASas supported by an F value of 1.20 with a significanceof p = 0.30. Similarities were also supported by non-significance in the pair-wise comparisons of differences(ANOVA) for all groups as follows: computer /con-trol, p = 0.68 computer/flip, p = 0.95, flip/control,p = 0.32. The 95 percent confidence interval furthersupported the similarities.

The mean values of the two intervention and the con-trol groups using the “pain spot” evaluation tool alsosupported equivalency with an F value of 1.27 and a sig-nificance of p = 0.29. Similarities were also supportedby the non-significant pair-wise comparisons (ANO-VA) for all groups as follows: CASP /control, p =0.45; CASP/FLIP, p = 0.99; FLIP/control, p = 0.41.The 95 percent confidence interval further supportedthe similarities (see Table 2).

The reduction in pain from the CASP interventionwas 73% using the VAS scale and 70% using the PSAtool. Reduction of pain reported from the FLIP subjectswas 64% using the VAS and 62% using the PSA tool


Table 2ANOVA: pair wise comparison of group means for cumulative pain index before theintervention was applied as measured by visual analog scale

Tamhane

Mean 95% Confidence Interval(I) (J) Difference (I-J) Sig. Lower bound Upper bound

computer control 2.25 0.68 −3.26 7.77flip control 3.34 0.32 −8.59 1.89flip computer 1.09 0.95 −4.68 6.87

Table 3ANOVA comparison of group mean differences for pain from intake to end ofintervention as evaluated by VAS

Tamhan

Mean 95% Confidence(I) (J) Difference (I-J) Sig. Lower bound Upper bound

computer control 10.80 0.000 6.12 15.50flip control 10.30 0.000 −14.48 −6.14flip computer −.050 0.994 −5.81 4.81

Test Groupflipcontrolcomputer

Pain

inde

x,m

ean

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

Fig. 8. Mean value of pain index before the Intervention as measured by VAS. Computer = Computer Assissted Stretching Program.

(in all cases p < 0.001). There was an increase inpain reported from the control subjects of 1% usingboth the VAS and the PSA (See Table 3, Figs 7, 8 and9). The differences in the percent of improvement forthe CASP and FLIP interventions were not found to besignificant.

When a Pearson’s Correlation comparing length oftime the interventions were used during the 15 days ofintervention with the reduction in pain the correlationwas found to be r = 0.48, (p < 0.001). When the VASfor pain was compared with the ergonomic grade of the

workstation at intake, r = (−) 0.042, (p = 0.73) forVAS.

The VAS assessment tool was compared to the PSAtool using Pearson’s Correlations to compare the nu-merical sum of the pain indices reported by each ofthe 68 subjects. The pre-intervention VAS to PSA toolresulted in an r = 0.75 (p < 0.001); post interventionVAS when compared with the PSA resulted in an r =0.86 (p < 0.001) and the difference in the pre and postVAS to the PSA resulted in an r = 0.76 (p < 0.001).

The following are noteworthy comments from the pre


flipcontrolcomputer

Mea

npa

inin

dex

afte

r(b

y V

AS

)

14

12

10

8

6

4

2

Fig. 9. Mean value of pain index after intervention Computer = Computer assisted stretching program intervention.

and post qualitative surveys and daily journals: Thirtypercent of the treatment groups (CASP and FLIP) re-ported that they had no pain at the end of the 15-days ofintervention. Seventy eight percent of the participantsrated the ergonomics of his or her workstation as “bad.”The study subjects rated poor ergonomics as the pri-mary reason that they had pain in both the pre and postintervention groups. This was followed by “no breaks.”The most common comments in the daily logs werethat “the stretching feels good” (13 times), and that “theprogram has helped” (12 times). No comments weremade regarding work productivity being affected.

4. Discussion

The data analysis supported a statistically significantdecrease in pain when evaluated by both the VAS andPSA evaluation tools for both the CASP and the FLIPintervention groups and the hypothesis was supported.Reduction in symptoms as measured by the VAS toolwas 74% for the CASP group and 64% for the FLIPgroup. The non-treatment control group was one per-cent worse at the end of the three-week period. Whenthe mean values of the “FLIP” and “CASP” groupswere compared, however, there was no significant dif-ference in two treatment outcomes.

The favorable effects may have been due to the in-tervention alone, that someone was acknowledging thesubjects’ complaints or may have been due to the friend-

ly voice and smiling face incorporated in the computerprogram. With the similarity in outcomes of the twotypes of media (computer vs. hard copy) there shouldhave been a difference in outcomes if there was a “me-dia” affect and there was not.

The same physical therapist performed the intake andouttake evaluations and that may have brought aboutsome unintentional bias. Analysis of the pre and postintervention results was deferred until all of the datafor the study were collected, and the initial assessmentwas not consulted for the outtake evaluation. Sincethe participants were using visual analog scales andrandom pain spots, bias should have been buffered, butremained a possibility.

Eighty-eight percent of the subjects in this studywere female. This may have been influenced by severalfactors. All of the secretaries and most of the clericalworkers in this population of convenience were womenand therefore more likely to be exposed to the offend-ing stimulus. In other populations studied, when allconditions were equal, females who were working withcomputers were found to have a significantly higher in-cidence of neck and shoulder disorders when comparedwith their male counterparts [6,23,49].

Ergonomics should not have played a role in theoutcomes since the workstations were not altered orchanged either before or during the time that the sub-jects were taking part in the study. This was confirmedby before and after pictures. In areas where more thanone subject was using the intervention, group support


may have been a factor in the outcomes, but similarlypositive results were demonstrated in both the isolatedand the group situations.

In the case of the “pain spot” assessments, the evalu-ation tool was not as sensitive as the VAS. However, nosignificant differences were seen in the pair-wise com-parisons of the means of the pre/ post intervention orcontrol groups. In addition, the Pearson’s Correlationsupported a similarity between the VAS and the PSAevaluation tools of between r = 0.76 and .86.

The stretching interventions appeared to be effectivein decreasing pain even though seated work, awkwardpositions, overuse, poor ergonomics, poor posture, age,de-conditioning, stress on bone and connective tissues,behavioral issues, and general work environment werenot changed. The only changes were the use of periodicstretching exercises as directed by an impersonal mediaand the attention given to complaints of pain. Sinceseveral studies have given attention to their subjectsand used computer programs to encourage breaks fromwork, without similar positive results, this may also notbe an issue. What did change was that a variety ofstretches was introduced in a timely manner. This mayhave prevented static muscle loading, decreased bloodflow to the area and the associated muscle spasms [11–13,17,20,39,40,43,51].

Seventy-eight percent of the participants in this studysubjectively rated the ergonomics of their workstationas “bad.” After the post intervention evaluations werecompleted for all subjects in a given area of the cam-pus, the researcher suggested ergonomic changes forthe participants’ workstations. Of 20 participants withadjustable keyboard heights and angles, none of thesubjects knew how to use the adjustment knobs thatwere an integral part of the keyboard. This remainsin agreement with the findings of Alexander who re-ported that seventy-four percent of 404 office-supportemployees were “not aware of the ergonomic changesthat could be made at their workstations” [2].

This intervention was used for a total of three weekswith each subject. Long term assessments were notdone. The outcomes of this research suggest a possibletreatment regime that may address the acute phase ofpain, while long term outcomes are unknown.

Eighty-eight percent of the participants were whitefemales from Appalachia. The external application ofthe program shows promise,but will need to be repeatedwith a larger, more representative population.

When comparing the specific areas of pain identifiedby the subjects in this study with other studies, thefindings were similar [2,11]. While subjects were asked

to comment on any interference in work productivitythat the stretching programs might have caused, nonewas reported. Some did complain that the kitchen timeron the FLIP version of the stretches was too loud andthat was modified by placing a piece of tape over thespeaker on the device to decrease the volume.

5. Conclusions

When subjects were reminded to perform stretch-es once every 6 minutes while seated at a computerworkstation, associated pain was significantly reduced.The type of media used to prompt stretching while atthe computer was not related to a significant differencein outcomes. “Pain Spot” Assessments may be a re-liable tool for evaluating pain. A study that extendsthe stretching protocol to a larger population with anextended follow-up is recommended.

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Appendix A: Workstation evaluationSubject # Picture # Date

Workstation and picture evaluation: A 17-point scalefor evaluation of computer workstations and pictures.One point is to be deducted for each problem areadetected. References that support the use of each itemin the protocol follow the statements.

1. Keyboard type is ergonomic [13,21,28,48]2. The mouse is held using a neutral position of the

wrist [21,28,35]3. Top of computer screen is at the level of the eyes

(within 15 degrees) [13,21,25,28,35,36]4. Chair height is adjustable [21,28,35]5. There is space between back of knees and front

edge of chair [13,21,34,35]

6. There are supportive arms on chair [13,21,28]7. The back on the chair is supportive [13,21,24,

34–36]8. The back of the chair adjustable [13,21,24,28,

35]9. There is a lumbar support [13,21,35]

10. Elbow angle is 70-90 degrees when hands areon keyboard [21,24,28,35,36]

11. Elbows are supported when using the key-board [12,13,16,21]

12. Elbows are supported when using the mouse [13,16,21,30,31]

13. Wrist angle is within 10 degrees of neutral whenusing the keyboard [13,21,28,34,35,48]

14. The feet touch on floor [13,21,28,34,35]15. A 70–90 degree angles of the knees, and 90

degree angle of the buttocks is evident whenseated at the workstation [13,21,28,34,35]

16. There is a document holder at eye level [13,21,28,35,36]

17. Glasses do not alter the neck position from neu-tral when using the computer [1,21,24,28,34,35]

This protocol for assessment of individual worksta-tion risk factors was based upon consensus of the fol-lowing authoritative input as published in the followingliterature [1,13,16,21,24,25,28,30,31,34–37,48].

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