Working postures of dentists and dental hygienists. Evaluation of ergonomic factors and postures that cause muscle pains in dentistry students’ bodies Effect of magnification lenses on student operator posture. Effect of magnification loupes on dental hygiene student posture. Reducing musculoskeletal disorders among computer operators: comparison between ergonomics interventions at the workplace The burden and determinants of neck pain in workers: results of the Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders. Ergonomic intervention: its effect on working posture and musculoskeletal symptoms in female biomedical scientists. Musculoskeletal disorders and occupational exposures: How should we judge the evidence concerning the causal association? Assessment of dental student posture in two seating conditions using RULA methodology – a pilot study The Effect of an Ergonomic Intervention on Musculoskeletal, Psychosocial and Visual Strain of VDT Data Entry Work: The United States Part of the International Study Multi dimensional system for evaluating preventive program for upper extremity disorders among computer operators. Evaluation of Two Preventive Interventions for Reducing Musculoskeletal Complaints in Operators of Video Display Terminals Predictors of Persistent Elbow Tendonitis Among Auto Assembly Workers The association between postural alignment and psychosocial factors to upper quadrant pain in high school students: a prospective study. Effects of ergonomic intervention on work-related upper extremity musculoskeletal disorders among computer workers: a randomized controlled trial A prospective study of computer users: II. Postural risk factors for musculoskeletal symptoms and disorders. Prevalence of work-related musculoskeletal symptoms of the neck and upper extremity among dentists in China Participatory ergonomics to reduce exposure to psychosocial and physical risk factors for low back pain and neck pain: results of a cluster randomised controlled trial A dental stool with chest support reduces lower back muscle activation The effectiveness of a training method using self-modeling webcam photos for reducing musculoskeletal risk among office workers using computers. The Effect of an Ergonomic Intervention on Musculoskeletal, Psychosocial and Visual Strain of VDT Data Entry Work: The Polish Part of the International Study Breaking up workplace sitting time with intermittent standing bouts improves fatigue and musculoskeletal discomfort in overweight/obese office workers The Effect of an Ergonomic Intervention on Musculoskeletal, Psychosocial and Visual Strain of VDT Entry Work: Organization and Methodology of the International Study
A joint study was conducted by a manufacturer of dental stools in the Midwest of the United States and Marquette University to measure the occupational postures of dentists and dental hygienists . The postures of 10 dentists and 10 dental hygienists were assessed using work sampling and video techniques .  Postural data of the neck , shoulders and lower back were recorded from video and categorized into 30-degree intervals : o ( neutral posture of respective joint ) , 30 , 60 and 90 degrees . Each subject 's postures were observed while they were treating patients during a four-hour period , during which 100 observations of postures were recorded at r and om times . Compared to st and ing , dentists and dental hygienists were seated 78 percent and 66 percent of the time , respectively . Dentists and dental hygienists flexed their trunk at least 30 degrees more than 50 percent of the time . They flexed their neck at least 30 degrees 85 percent of the time during the four-hour duration , and their shoulders were elevated to the side of their trunk ( abducted ) at least 30 degrees more half of the time . The postures of the trunk , shoulders , and neck were primarily static . This data base of postures can be used by dental professionals and ergonomists to assess the risk dentists and dental hygienists are exposed to musculoskeletal disorders , such as low back pain or shoulder tenosynovitis , from deviated joint postures . They could use these data to select dental furniture or dental devices that promote good body posture , i.e. , reduce the magnitude and duration of deviated joint postures , which , in theory , would decrease the risk of musculoskeletal disorders Background Work-related musculoskeletal disorders commonly experienced by dental professionals are one of the main occupational health problem affecting their health and well-being . This study was conducted to evaluate  ergonomic factors and profession-related postures  and also investigate relationship between demographic factors and work condition with pain in dental students . Material and Methods 60 freshman and sophomore dentistry students were r and omly chosen as the subjects of control group , and 60 of 5th and 6th-year students were selected as the members of exposure group . Data related to the subjects such as sex , doing exercise , severity of musculoskeletal pain were obtained through question naire . Students ’ postures were directly observed while treating patients and they were scored by REBA method . Data were analyzed by SPSS software using Man-Whitney , Kruskal-Wallis , Spearman and Kendall correlation tests . Results 80.8 % of the subjects were not aware of the correct ergonomic postures for dental procedures . Severity of musculoskeletal pain in the exposure group ( 15.9± 4.2 ) was significantly higher than the control group ( 10.5 ±3.2 ) , ( p < 0.001 ) . Risk of the most subjects ( 84 % ) was at the medium level . Students who were more involved in clinical activities experienced more muscular pains . Conclusions The musculoskeletal disorders are probable prolonged in working hours in static positions , incorrect work postures , implying more force and even tools and instruments . Therefore , students who are aware of ergonomic principals of their own profession would be able to maintain their health through activities and lifelong . Key words : Posture , dentistry , students , musculoskeletal pain A distinct body of literature supports the association between clinical postures of the dental practitioner and work-related musculoskeletal disorders ( WRMD ) . Several aids or devices have been tested to improve clinical posture in the interest of decreasing WRMD . The use of magnification lenses while performing dental procedures may increase the quality of work and decrease the likelihood of musculoskeletal problems . To date , only anecdotal and personal opinions had existed regarding the benefits of using magnification lenses , and no empirical evidence had authenticated the contention that use of magnification lenses exerts a positive change in operator posture . The objective of this study was to assess the effect magnification lenses had on the posture of dental hygiene students . Using a r and omized crossover design , research ers videotaped nineteen senior dental hygiene students performing an intra-oral procedure with and without the use of magnification lenses . The tapes were then evaluated by a panel of five dental hygiene educators calibrated in the use of Branson 's Posture Assessment Instrument ( PAI ) . Results of a paired t-test indicate that the posture of the students while wearing magnification lenses was more acceptable ( p=.019 ) than when wearing traditional safety glasses . Results of this study indicate a quantifiable change in acceptability of posture for clinicians wearing magnification lenses  and suggest that the use of such lenses in dental education may be warranted The chair-side work posture of dental hygienists has long been a concern because of health-related problems potentially caused or exacerbated by poor posture . The purpose of this study was to investigate if using magnification loupes improved dental hygiene students ' posture during provision of treatment . The treatment chosen was h and -scaling , and the effect of the timing of introduction of the loupes to students was also examined . Thirty-five novice dental hygiene students took part in the study . Each student was assessed providing dental hygiene care with and without loupes , thus controlling for innate differences in natural posture . Students were r and omized into two groups . Group one used loupes in the first session and did not use them for the second session . Group two reversed this sequence . At the end of each session , all students were videotaped while performing scaling procedures . Their posture was assessed using an adapted version of Branson et al. 's Posture Assessment Instrument ( PAI ) . Four raters assessed students at three time periods for nine posture components on the PAI . A paired t-test compared scores with and without loupes for each student . Scores showed a significant improvement in posture when using loupes ( p<0.0001 ) , and these improvements were significantly more pronounced for students starting loupes immediately on entering the program compared with students who delayed until the second session ( p<0.1 ) . These results suggest a significant postural benefit is realized by requiring students to master the use of magnification loupes as early as possible within the curriculum Typing is associated with musculoskeletal disorders ( MSDs ) caused by multiple risk factors . This control study aim ed to evaluate the efficacy of a workplace intervention for reducing  MSDs among computer workers . Sixty-six subjects with and without MSD were assigned consecutively to one of three groups : ergonomics intervention ( work site and body posture adjustments , muscle activity training and exercises ) accompanied with biofeedback training , the same ergonomics intervention without biofeedback and a control group . Evaluation of MSDs , body posture , psychosocial status , upper extremity ( UE ) kinematics and muscle surface electromyography were carried out before and after the intervention in the workplace and the motion lab . Our main hypothesis that significant differences in the reduction of MSDs will exist between subjects in the study groups and controls was confirmed ( χ2 = 13.3 ; p = 0.001 ) . Significant changes were found in UE kinematics and posture as well . Both ergonomics interventions effectively reduced MSD and improved body posture . Practitioner Summary : This study aim ed to test the efficacy of an individual workplace intervention programme among computer workers by evaluating musculoskeletal disorders ( MSDs ) , body posture , upper extremity kinematics , muscle activity and psychosocial factors were tested . The proposed ergonomics interventions effectively reduced MSDs and improved body posture STUDY DESIGN Systematic review and best evidence synthesis . OBJECTIVES To describe the prevalence and incidence of  neck pain and disability in workers ; to identify risk factors for neck pain in workers ; to propose an etiological diagram ; and to make recommendations for future research . SUMMARY OF BACKGROUND DATA Previous review s of the etiology of neck pain in workers relied on cross-sectional evidence . Recently published cohorts and r and omized trials warrant a re- analysis of this body of research . METHODS We systematic ally search ed Medline for literature published from 1980 - 2006 . Retrieved articles were review ed for relevance . Relevant articles were critically appraised . Articles judged to have adequate internal validity were included in our best evidence synthesis . RESULTS One hundred and nine papers on the burden and determinants of neck pain in workers were scientifically admissible . The annual prevalence of neck pain varied from 27.1 % in Norway to 47.8 % in Québec , Canada . Each year , between 11 % and 14.1 % of workers were limited in their activities because of neck pain . Risk factors associated with neck pain in workers include age , previous musculoskeletal pain , high quantitative job dem and s , low social support at work , job insecurity , low physical capacity , poor computer workstation design and work posture , sedentary work position , repetitive work and precision work . We found preliminary evidence that gender , occupation , headaches , emotional problems , smoking , poor job satisfaction , awkward work postures , poor physical work environment , and workers ' ethnicity may be associated with neck pain . There is evidence that interventions aim ed at modifying workstations and worker posture are not effective in reducing the incidence of neck pain in workers . CONCLUSION Neck disorders are a significant source of pain and activity limitations in workers . Most neck pain results from complex relationships between individual and workplace risk factors . No prevention strategies have been shown to reduce the incidence of neck pain in workers This study investigates the effect of ergonomic intervention on working posture and musculoskeletal symptoms in female biomedical scientists . The Nordic musculoskeletal question naire ( NMQ ) , body discomfort chart ( BDC ) and rapid upper-limb assessment ( RULA ) are the tools for assessment . The study was conducted in three phases : pre-intervention , intervention and post-intervention . Pre-intervention , 79 % of subjects reported a three-month prevalence of symptoms , and these were reported more frequently by those working in haematology/transfusion . Analysis by RULA showed that the majority ( 59 % ) of postures had a gr and score of four . A further 24 % had scores of five or six . The highest frequency of poor postures was seen in haematology/transfusion . Intervention comprised physical workplace changes , a seminar , and advice on risk factors . In the post-intervention phase , baseline measurements were repeated . Reporting of three-month prevalence of symptoms had decreased to 54 % , and reports of body discomfort also had decreased . The majority ( 64 % ) had a RULA gr and score of three . No observed postures had scores of five or six . In conclusion , ergonomic intervention result ed in an improvement in working postures , and a decrease in the prevalence of musculoskeletal symptoms and body discomfort . Analysis of findings indicate that RULA scores generally corresponded with reporting of symptoms ( NMQ ) and discomfort ( BDC ) Musculoskeletal disorders ( MSDs ) affecting the back , upper and lower extremities are widespread in the general population , implying a variety of causal factors . Multiple causes are not mutually exclusive , and a high background rate does not preclude associations with specific factors that are uncommon in the general population . MSDs have well-documented associations with occupational ergonomic stressors such as repetitive motion , heavy lifting , non-neutral postures , and vibration . Organizational features of the work environment , such as time pressure and low decision latitude , may also play a role , at least by potentiating the effects of physical loading . Numerous systematic review s have mostly concurred with these overall findings . Nevertheless , some continue to debate whether MSDs are sometimes work-related , even for those performing jobs with repetitive and routinized tasks , heavy lifting , and /or pronounced postural strain . This article discusses ( 1 ) some epidemiologic features of MSDs that underlie that debate ; and ( 2 ) the question of what should appropriately be considered a gold st and ard for scientific evidence on an etiological question such as the health effects of a non-voluntary exposure , such as an occupational or environmental agent . In particular , r and omized clinical trials have little relevance for determining the health effects of non-therapeutic risk factors Objectives To assess dental students ' posture on two different seats in order to determine if one seat predisposes to a difference in working posture . Design A between-subject experimental design was selected . Setting The study was undertaken at the University of Birmingham School of Dentistry in 2006 . Subjects ( material s ) and methods Sixty second year dental students at the University of Birmingham who were attending their fi rst classes in the phantom head laboratory were r and omly selected and allocated to two different seats ( 30 Bambach Saddle Seats and 30 conventional seats ) . Students were trained in the use of the seats . After ten weeks , the students were observed , photographs were taken by the research er and these were assessed using Rapid Upper Limb Assessment ( RULA ) . Main outcome measures The posture of the students was assessed using the RULA . Each student was given a risk score . A Mann Whitney test was used for statistical analysis . Results The results indicated that the students using the conventional seat recorded signifi cantly higher risk scores ( p < 0.05 ) when compared with the students using Bambach Saddle Seat , suggesting an improvement in posture when using the Bambach Saddle Seat . Conclusion RULA has identifi ed that dental students using a Bambach Saddle Seat were able to maintain an acceptable working posture during simulated dental treatment and this seating may reduce the development of work-related musculoskeletal disorders The United States MEPS ( musculoskeletal — eyestrain — psychosocial — stress ) study consisted of 1 group of 28 female data entry operators . The intervention was in 3 parts : workstation re design ( including advanced ergonomic chairs , motorized adjustable workstations , advanced adjustable keyboards , adjustable copyholders , adjustable footrests , monitor support surfaces ) and ergonomic training/coaching and corrective lenses . After the intervention , statistically significant reductions in physical signs ( trigger points , neck and shoulder mobility ) , subjective reports of intensity and frequency of musculoskeletal pain , and subjective reports of visual problems were observed . Static load during the work sample , as assessed by experts , improved after the intervention as did measured postural angles of head and trunk and subjective assessment of users of ergonomic characteristics of the workplaces . For all of these measures , improvements observed 1 month after intervention were also observed in the 1-year follow-up . Trapezius load , as assessed by electromyography ( EMG ) , decreased after intervention , but then increased in the follow-up . The increase was interpreted as a calibration problem Typing is associated with musculoskeletal complaints ( MSCs ) , caused by multiple risk factors . Although a wide variety of ergonomic intervention programs were conducted to reduce risk factors and MSC 's , only few of them were found evidence based . This study aim ed to test the efficacy of a workplace intervention in reducing MSC 's among computer workers . 66 computer workers were assigned r and omly to one of three intervention programs : ergonomic intervention including biofeedback , intervention without biofeedback and control group without intervention . The efficacy was tested by advanced assessment including ; pain location and severity , posture at work , upper extremity 3D kinematics , muscle activity and psychosocial status . Working hypothesis ; significant score differences will be found between the study groups which underwent ergonomic intervention and the control group on the following measures : pain complaints , upper extremity kinematics , muscle activity and psychosocial status . Significant differences were found between pre and post intervention and between research groups and the control group in pain , posture and motion . The ergonomic intervention with biofeedback had no unique contribution in comparison to other interventions . In conclusion ; the proposed intervention program was found efficient for reducing pain among computer workers Background and Purpose The purpose of this study was to evaluate the efficacy of a preventive ergonomic intervention , which was provided by physical therapists , on spinal and upper-extremity work-related posture and symptom complaints of workers who use video display terminals ( VDT ) . Subjects Two hundred employees who spent at least 20 hours per week at a VDT were r and omly divided into 2 groups . Group E received the ergonomic intervention and an informative brochure , and group I received only the brochure . Methods Both groups were evaluated at the beginning of the study and at a follow-up 5 months later . The following tools were used : a pain drawing and the Rapid Entire Body Assessment ( REBA ) method to assess spinal and upper-extremity work-related posture . Results Group E had a lower REBA score and reduced lower back , neck , and shoulder symptoms compared with group I. Discussion and Conclusion The results suggest that a personalized preventive ergonomic intervention can improve spinal and upper-extremity work-related posture and musculoskeletal symptoms for workers who use VDTs Introduction : Lateral and medial epicondylitis associated with work activity is a common upper extremity musculoskeletal disorder with a prevalence of 4–30 % depending upon the work setting and diagnostic criteria . The influence of treatment , ergonomic factors , medical history , psychosocial variables , and aging on the improvement of symptoms has not been well defined . Methods : This was a prospect i ve cohort study of a cohort of 45 workers with active elbow tendonitis for an average of 13 months .  Complete resolution of symptoms was the defined outcome measure . Results : The predictive factors for persistent elbow tendonitis included older age ( OR = 1.1 , 95 % CI : 0.99 , 1.33 ) , higher h and repetition level for their job(s ) ( OR = 2.5 , 95 % CI : 1.00 , 6.25 ) , more deviation from a neutral wrist position during the work activity ( OR = 2.0 , 95 % CI : 0.80 , 5.56 ) , and lower perceived decision authority on the job ( OR = 0.9 , 95 % CI : 0.79 , 0.98 ) . Other ergonomic , psychosocial , and electrophysiologic measures were not predictive . The models had relatively high sensitivity and specificity . Treatment effects could not be evaluated due to incomplete data available . Conclusions : Older workers with jobs requiring more repetition and awkward wrist postures , and less decision authority were less likely to have resolution of their elbow tendonitis . Implication s : Workers at highest risk for persistent elbow tendonitis should be placed at jobs with lower repetition levels and that use more neutral wrist postures . Effective interventions must address both the ergonomic and psychosocial risk factors in a multifaceted approach to this problem Prolonged sitting and psychosocial factors have been associated with musculoskeletal symptoms among adolescents . However , the impact of prolonged static sitting on musculoskeletal pain among South African high school students is uncertain . A prospect i ve observational study was performed to determine whether sitting postural alignment and psychosocial factors contribute to the development of upper quadrant musculoskeletal pain ( UQMP ) in grade ten high school students working on desktop computers . The sitting postural alignment , depression , anxiety and computer use of 104 asymptomatic students were measured at baseline . At three and six months post baseline , the prevalence of UQMP was determined . Twenty-seven students developed UQMP due to seated or computer-related activities . An extreme cervical angle ( < 34.75 degrees or > 43.95 degrees ; OR 2.8 ; 95 % CI : 1.1 - 7.3 ) and a combination of extreme cervical and thoracic angles ( < 63.1 degrees or > 71.1 degrees ; OR 2.2 ; 95 % CI : 1.1 - 5.6 ) were significant postural risk factors for the development of UQMP . Boys with any extreme angle were more likely to suffer pain compared with boys with all middle range angles ( OR 4.9 ; 95 % CI : 1.0 - 24.5 ) . No similar effect was found for girls . There was no strong relationship between depression , anxiety , computer exposure and UQMP among South African high school students Purpose The aim of the study was to determine effects of ergonomic intervention on work-related upper extremity musculoskeletal disorders ( WUEMSDs )  among computer workers . Methods Four hundred computer workers answered a question naire on work-related upper extremity musculoskeletal symptoms ( WUEMSS ) . Ninety-four subjects with WUEMSS using computers at least 3 h a day participated in a prospect i ve , r and omized controlled 6-month intervention . Body posture and workstation layouts were assessed by the Ergonomic Question naire . We used the Visual Analogue Scale to assess the intensity of WUEMSS . The Upper Extremity Function Scale was used to evaluate functional limitations at the neck and upper extremities . Health-related quality of life was assessed with the Short Form-36 . After baseline assessment , those in the intervention group participated in a multicomponent ergonomic intervention program including a comprehensive ergonomic training consisting of two interactive sessions , an ergonomic training brochure , and workplace visits with workstation adjustments . Follow-up assessment was conducted after 6 months . Results In the intervention group , body posture ( p < 0.001 ) and workstation layout ( p = 0.002 ) improved over 6 months ; furthermore , intensity ( p < 0.001 ) , duration ( p < 0.001 ) , and frequency ( p = 0.009 ) of WUEMSS decreased significantly in the intervention group compared with the control group . Additionally , the functional status ( p = 0.001 ) , and physical ( p < 0.001 ) , and mental ( p = 0.035 ) health-related quality of life improved significantly compared with the controls . There was no improvement of work day loss due to WUEMSS ( p > 0.05 ) . Conclusions Ergonomic intervention programs may be effective in reducing ergonomic risk factors among computer workers and consequently in the secondary prevention of WUEMSDs BACKGROUND Despite widespread recommendations regarding posture during computer use , associations between specific postures and musculoskeletal health are not well characterized . METHODS Six hundred and thirty-two newly hired computer users were followed prospect ively to evaluate associations between posture and neck or shoulder ( N/S ) and h and or arm ( H/A ) musculoskeletal symptoms and musculoskeletal disorders . Participants ' postures were measured at entry and they reported symptoms on weekly diaries . Participants reporting symptoms were examined for specific disorders . Multivariate Cox regression models were used to estimate associations between postural variables and risk of symptoms and disorders , controlling for confounding variables . RESULTS Keying with an inner elbow angle > 121 degrees , greater downward head tilt , and presence of armrests on the participants chair were associated with lower risk of N/S symptoms or N/S disorders .  Keying with elbow height below the height of the " J " key and the presence of a telephone shoulder rest were associated with a greater risk of N/S symptoms or N/S disorders . Horizontal location of the " J " key > 12 cm from the edge of the desk was associated with a lower risk of H/A symptoms and H/A disorders . Use of a keyboard with the " J " key > 3.5 cm above the table surface , key activation force > 48 g , and radial wrist deviation of > 5 degrees while using a mouse was associated with a greater risk of H/A symptoms or H/A disorders . The number of hours keying/week was associated with H/A symptoms and disorders . CONCLUSIONS The results suggest that the risk of musculoskeletal symptoms and musculoskeletal disorders may be reduced by encouraging specific seated postures Objectives Studies from western countries show that dentists are vulnerable to work-related musculoskeletal disorders ( WMSDs ) of the neck and upper extremities , but little is known about their epidemiology among members of this rapidly growing profession in China . This study aims to investigate the prevalence of WMSDs and identify potential risk factors associated with their occurrence in the dental profession in China . Setting and participants A cross-sectional survey was carried out in 52 different hospitals in a large metropolitan city in China . A total of 304 question naires were distributed to respondents identified via stratified r and om sampling and 272 dentists ( 121 females and 151 males ) completed the survey . The response rate was 89.5 % . Outcomes Visual analogue score was used to record neck and upper limb musculoskeletal symptoms on a body chart . Work-related risk factors , including physical and psychosocial factors , were accounted for in the regression analysis . Results 88 % of the dentists reported at least one musculoskeletal disorder and 83.8 % suffered from neck pain . In the multivariate analyses , working hours per day were associated with neck pain ( OR=1.43 ; 95 % CI 1.03 to 1.98 ) . Inability to select the appropriate size of dental instrument was associated with shoulder ( OR=2.07 ; 95 % CI 1.00 to 4.32 ) and wrist/h and ( OR=2.47 ; 95 % CI 1.15 to 5.32 ) pain . As for psychosocial factors , high job dem and was associated with symptoms in the shoulder ( OR=1.09 ; 95 % CI 1.00 to 1.18 ) , elbow ( OR=1.11 ; 95 % CI 1.03 to 1.19 ) and wrist/h and ( OR=1.09 ; 95 % CI 1.02 to 1.17 ) . Regular physical exercise was associated with decreased neck pain ( OR=0.37 ; 95 % CI 0.14 to 1.00 ) . Conclusions The prevalence of WMSDs among Chinese dentists is high . Specifically , long working hours , inability to select the appropriate size of dental instrument and high job dem and are the most significant risk factors Objectives This study investigated the effectiveness of the Stay@Work participatory ergonomics programme to reduce workers′ exposure to psychosocial and physical risk factors . Methods 37 departments ( n=3047 workers ) from four Dutch companies participated in this cluster r and omised controlled trial ; 19 ( n=1472 workers ) were r and omised to an intervention group ( participatory ergonomics ) and 18 ( n=1575 workers ) to a  control group ( no participatory ergonomics ) . During a 6 h meeting guided by an ergonomist , working groups devised ergonomic measures to reduce psychosocial and physical workload and implemented them within 3 months in their departments . Data on psychosocial and physical risk factors for low back pain and neck pain were collected at baseline and after 6 months . Psychosocial risk factors were measured using the Job Content Question naire and physical risk factors using the Dutch Musculoskeletal Question naire . Intervention effects were studied using multilevel analysis . Results Intervention group workers significantly increased on decision latitude ( 0.29 points ; 95 % CI 0.07 to 0.52 ) and decision authority ( 0.16 points ; 95 % CI 0.04 to 0.28 ) compared to control workers . However , exposure to awkward trunk working postures significantly increased in the intervention group ( OR 1.86 ; 95 % CI 1.15 to 3.01 ) compared to the control group . No significant differences between the intervention and control group were found for the remaining risk factors . After 6 months , loss to follow-up was 35 % in the intervention group and 29 % in the control group . Conclusion Participatory ergonomics was not effective in reducing exposure to psychosocial and physical risk factors for low back pain and neck pain among a large group of workers . Trial registration IS RCT N27472278 Activation of back musculature during work tasks leads to fatigue and potential injury . This is especially prevalent in dentists who perform much of their work from a seated position . We examined the use of an ergonomic dental stool with mid-sternum chest support for reducing lower back muscle activation . Electromyography of lower back extensors was assessed from 30 dental students for 20 s during three conditions in r and om order : ( a ) sitting upright at 90 ° of hip flexion on a st and ard stool , ( b ) leaning forward at 80 ° of hip flexion on a st and ard stool , and ( c ) leaning forward at 80 ° of hip flexion while sitting on an ergonomic stool . Muscular activity of the back extensors was reduced when using the ergonomic stool compared to the st and ard stool , by 33–50 % ( p < 0.01 ) . This suggests a potential musculoskeletal benefit with use of a dental stool with mid-sternum chest support An intervention study was conducted to examine the effectiveness of an innovative self-modeling photo-training method for reducing musculoskeletal risk among office workers using computers . Sixty workers were r and omly assigned to either : 1 ) a control group ; 2 ) an office training group that received personal , ergonomic training and workstation adjustments or 3 ) a photo-training group that received both office training and an automatic frequent-feedback system that displayed on the computer screen a photo of the worker 's current sitting posture together with the correct posture photo taken earlier during office training . Musculoskeletal risk was evaluated using the Rapid Upper Limb Assessment ( RULA ) method before , during and after the six weeks intervention . Both training methods provided effective short-term posture improvement ; however , sustained improvement was only attained with the photo-training method . Both interventions had a greater effect on older workers and on workers suffering more musculoskeletal pain . The photo-training method had a greater positive effect on women than on men A group of routine data entry operators ( female ) was included in the Polish MEPS ( musculoskeletal — eyestrain— psychosocial — stress ) study . Before the intervention , ergonomic assessment revealed improper working conditions such as inadequate lighting , uncomfortable chairs , and lack of forearm and wrist support while medical examination revealed that trapezius muscle load along with upper arm , head and back angles were higher than advisable . Subjects complained about neck and shoulder pain , visual problems , and psychosocial conditions . The ergonomic intervention included installation of new luminaires and Venetian blinds , new chairs , repair of ventilators , and optometric corrections . The results after the intervention showed mainly improvement in chair comfort , lighting conditions , visual strain , and sitting posture . However , financial limitations did not allow satisfactory completion of the intervention leading to a mixed interpretation of the results Objectives To examine whether the introduction of intermittent st and ing bouts during the workday using a height-adjustable workstation can improve subjective levels of fatigue , musculoskeletal discomfort and work productivity relative to seated work . Methods Overweight/obese office workers ( n=23 ; age 48.2±7.9 years , body mass index 29.6±4 kg/m2 ) undertook two , 5-day experimental conditions in an equal , r and omised ( 1:1 ) order . In a simulated office environment , participants performed their usual occupational tasks for 8 h/day in a : seated work posture ( SIT condition ) ; or interchanging between a st and ing and seated work posture every 30 min using an electric , height-adjustable workstation ( ST AND -SIT condition ) . Self-administered question naires measuring fatigue , musculoskeletal discomfort and work productivity were performed on day 5 of each experimental condition . Results Participants ’ total fatigue score was significantly higher during the SIT condition ( mean 67.8 ( 95 % CI 58.8 to 76.7 ) ) compared with the ST AND -SIT condition ( 52.7 ( 43.8 to 61.5 ) ; p<0.001 ) . Lower back musculoskeletal discomfort was significantly reduced during the ST AND -SIT condition compared with the SIT condition ( 31.8 % reduction ; p=0.03 ) . Despite concentration/focus being significantly higher during the SIT condition ( p=0.006 ) , there was a trend towards improved overall work productivity in favour of the ST AND -SIT condition ( p=0.053 ) . Conclusions Transitioning from a seated to a st and ing work posture every 30 min across the workday , relative to seated work , led to a significant reduction in fatigue levels and lower back discomfort in overweight/obese office workers , while maintaining work productivity . Future investigations should be directed at underst and ing whether sustained use of height-adjustable workstations promote concentration and productivity at work . Trial Registration Number ACTRN12611000632998 This special issue of the International Journal of Occupational Safety and Ergonomics ( JOSE ) reports the results from an extensive multinational and multidisciplinary collaborative investigation of the impacts on  visual display terminal ( VDT ) work  of musculoskeletal , visual , ergonomic , and psychosocial factors . For brevity , this effort has been referred to as the MEPS project ( musculoskeletal — eyestrain — psychosocial — stress ) . This paper lays out the basic method ological structure of the study . The study was conducted in 4 countries utilizing VDT data entry workers as the primary subject population . A battery of objective and subject assessment measures , including muscle load , visual function , physical and visual strain , postural , ergonomic and psychosocial factors , were assessed at 3 different points in time . A pre-test was given prior to an ergonomic intervention . Two post-tests were given 1 month and 1 year after the ergonomic intervention
CONCLUSIONS Based on a limited number of studies , the use of ergonomic saddle seats and dental loupes leads to improved working postures .
The use of loupes appears to relieve shoulder , arm and h and pain .
However , their effect on neck pain is scarce .
None of the studies reported on the effect of the saddle seats on musculoskeletal pain .
OBJECTIVES Musculoskeletal disorders affect a high percentage of dentists , dental hygienists and therapists .
Static and awkward working postures are considered as major risk factors .
Proper seat selection and use of magnification loupes are promoted for their ergonomic benefits .
The aim of this review was to evaluate the existing empirical evidence on the effect of the above interventions on ( i ) correction of poor posture and ( ii ) reduction in musculoskeletal pain .