Results Level of evidence from 54 high and medium quality studies showed moderate evidence of a positive effect of physical exercise .
Within this domain , there was strong evidence of a positive effect of workplace strength training .
There was limited evidence for ergonomics and strong evidence for no benefit of participatory ergonomics , multifaceted interventions , and stress management .
No intervention domains were associated with “ negative effects ” .
Conclusions The evidence synthesis recommends that implementing strength training at the workplace can reduce MSD  among workers with physically dem and ing work .
In regard to workplace ergonomics , there was not enough evidence from the scientific literature to guide current practice s. Based on the scientific literature , participatory ergonomics and multifaceted workplace interventions seem to have no beneficial effect on reducing MSD among this group of workers .
Purpose This systematic review investigates the effectiveness of workplace interventions to rehabilitate musculoskeletal disorders ( MSDs ) among employees with physically dem and ing work .
Lumbar Supports to Prevent Recurrent Low Back Pain among Home Care Workers
Context Lumbar supports are commonly used to prevent low back pain , but evidence on their effectiveness is lacking . Contribution This trial assigned 360 home care workers with a history of low back pain to a short course on healthy work habits , with or without worker-directed use of a lumbar support . Over 12 months , participants assigned to lumbar support had a similar number of sick days but fewer days with low back pain than did those assigned to the course only . Implication Adding lumbar supports to instruction on healthy work habits may decrease low back pain recurrence , but not absenteeism , among workers with previous low back pain . The Editors Low back pain is a common problem that results in high medical expenses , work absenteeism , and disability ( 1 ) . The reported 1-year prevalence ranges from 15 % to 40 % in a general population ( 2 ) and from 44 % to 72 % among home care workers ( 3 , 4 ) . Various ergonomic aids are marketed for the prevention of low back pain . Workers frequently use lumbar supports to prevent back pain ( 5 ) , but the effectiveness of such supports remains unclear . Recent systematic review s of the sparse evidence on lumbar supports ( 6 , 7 ) concluded that no evidence exists for the effectiveness of  lumbar supports  in the primary prevention of low back pain in the workplace , but 2 of the 4 included r and omized , controlled trials ( 8 , 9 ) reported that lumbar supports might be effective in workers with a history of low back pain ( secondary prevention ) . However , these findings were derived from subgroup analyses , and evidence from direct research on secondary prevention was not available . In cohort studies , a history of low back pain proved to be a strong predictor for the incidence of new episodes of low back pain ( 1012 ) . Home care workers with a history of low back pain may therefore be well suited to secondary preventive measures . In a previous uncontrolled feasibility study , we found that home care workers who had frequent episodes of low back pain reported adherence rates of 61 % to 81 % with lumbar supports and a 45 % decrease in pain intensity when using lumbar supports ( 13 ) . We design ed the current trial to evaluate the effectiveness of adding worker-directed use of lumbar supports to a short course on healthy working methods to reduce low back pain and work absenteeism among home care workers with a history of low back pain . Methods Design Our r and omized , controlled trial included 2 groups . The control group received a short refresher course on healthy working methods provided by their employer at the start of their employment ( Appendix ) ; primary and secondary care for the management of low back pain was available as usual ( 14 ) . The intervention group received a lumbar support in addition to usual care . The intervention and data collection continued for 12 months after enrollment . The Medical Ethical Committee of the Erasmus University Medical Center , Rotterdam , the Netherl and s , approved the study . Participants All participants were recruited from employees of a large home care organization in Rotterdam . During staff meetings , all present team members completed a brief survey about study inclusion criteria that was distributed and collected by the team managers . We included persons who performed medical care or domestic tasks as a home care worker , were experiencing low back pain symptoms at the time of inquiry or had experienced 2 or more episodes ( on 2 consecutive days ) of low back pain symptoms in the 12 months before the inquiry , did not have specific low back pain ( for example , due to rheumatoid arthritis or vertebral fractures ) , and were not pregnant at the start of the study . Because of a possible association between lumbar supports and increased blood pressure and heart rate , we excluded workers receiving medical treatment for high blood pressure ( 15 ) . Employees who met the inclusion criteria received detailed information about the trial , and those who agreed to participate provided written consent . R and omization In the Netherl and s , home care workers provide 1 of 8 functions , each of which requires different skills and tasks . To ensure a balance in workload and working conditions between the 2 study groups , we stratified r and omization by these 8 functions . We also stratified r and omization by low back pain experience at baseline ( current pain vs. past pain ) . The r and omization process used a computer-generated r and om-number table with 16 strata ( 2 low back pain by 8 workplace functions ) , arranged in blocks of 8 within each stratum . After baseline measurements were completed , colleagues who were not otherwise involved in the study and who were blinded to participants ' baseline characteristics used the r and om-number table to allocate each participant to 1 of the study groups . Intervention All participants in the intervention group were instructed to wear the lumbar supports on working days on which they had or expected they might develop low back pain . Participants could select 1 of 4 types of lumbar supports , supplied by Bauerfeind B.V. , Haarlem , the Netherl and s. LumboTrain and LumboTrain Lady are individually adjustable , hook- and -loop fastening , fully elastic supports that are available in 5 sizes for men or women . LumboLoc and LordoLoc are more structured supports , with integrated stays in the back , that have individually adjustable hook- and -loop fastenings and are available in 6 sizes . Participants chose the lumbar support on the basis of fit and wearing comfort , and they were not given advice to direct their choice from among the 4 available supports . When measured by the research er for the lumbar support , the participants were advised to wear the support for a few days in a row , regardless of low back pain , in order to become accustomed to it . The expected duration of wearability of the lumbar supports was 1 year . The costs of the lumbar supports were 75 for LumboTrain and LumboTrain Lady , 56 for LumboLoc , and 50 for LordoLoc . Outcome Measures Our primary outcome measures were the number of days that participants reported low back pain per month and the number of calendar days of sick leave that participants took during the 12-month intervention . Secondary outcome measures were the average severity of low back pain in the previous week , rated on a scale of 0 to 10 ( 16 ) , and functional status in the previous week , measured by using a Dutch translation of the Quebec Back Pain Disability Scale ( on which 0 corresponds to no disablement and 100 corresponds to fully disabled ) ( 17 , 18 ) . Participants used a calendar to record the days per month on which they experienced low back pain . The intervention group was also asked to record on the calendar whether they had worn the lumbar support ;  thus , the calendars also served as a monitor for adherence to therapy . The calendars were collected for review after 1 , 3 , 6 , 9 , and 12 months . The number of calendar days of sick leave was derived from the staff register and was provided by the home care organization at the end of the study ; this information covered 15 months , from 3 months before the start of the study until the end of the intervention . We could gather only general data on sick leave because employees are not obliged to specify their illness for the employer when they report themselves ill , and registration by a company doctor starts from 6 consecutive weeks of sick leave . We collected information on self-reported , low back painrelated sick leave ; however , this was not a predetermined outcome , and the results should be interpreted cautiously . We administered a question naire at baseline to obtain information on the secondary outcome measures and demographic characteristics ; history of low back pain ; job characteristics ( among others , the Job Content Question naire , Dutch translation [ 19 ] ) ; and other possible confounders , such as additional work ( hours per week and type ) , preference for study group assignment , confidence in pain reduction with use of the lumbar support ( scale of 0 to 10 ) , and confidence in improved functioning ( scale of 0 to 10 ) . Follow-up question naires were administered at 3 , 6 , 9 , and 12 months to measure the secondary outcomes . In the intervention group , these question naires also measured the general satisfaction with the lumbar support ( scale of 0 to 10 ) , several items on comfort of wearing ( 5-point Likert scale ) , and adherence to use of the lumbar support ( 7-point Likert scale ) . We recorded spontaneously reported side events and asked participants about side effects in the question naires . Statistical Analysis We estimated that with a power of 80 % , a significance level of 0.05 , and an SD of 20 days , we would need 140 participants in each study group to demonstrate a difference of 7 days of low back pain per year or sick leave per year between the 2 groups . To prevent inadequate power because of participant withdrawal or low adherence to therapy , we sought to enroll 400 home health care workers . We used a longitudinal marginal model with generalized estimating equation estimates to analyze the data , according to intention-to-treat principles . For the primary outcomes ( number of days of low back pain and number of days of sick leave ) , we used a negative-binomial count data model with a log-link and an exchangeable correlation structure . Covariates ( history of low back pain , body mass index , additional work , and pregnancy during follow-up ) were added to the model separately and were used in the final model if they statistically significantly contributed to the model ( P < 0.05 ) . The scale scores of the secondary outcomes were analyzed by using a normal distributed model and an exchangeable correlation structure . To investigate model misspecification and the effect of missing data , we performed sensitivity analyses in which we used various structures for the working correlation to estimate the models and used multiple imputation techniques to analyze 5 imputed data sets for missing data ( 20 ) . For all analyses , we used SAS ,
Results Level of evidence from 54 high and medium quality studies showed moderate evidence of a positive effect of physical exercise .
Within this domain , there was strong evidence of a positive effect of workplace strength training .
There was limited evidence for ergonomics and strong evidence for no benefit of participatory ergonomics , multifaceted interventions , and stress management .
No intervention domains were associated with “ negative effects ” .
Conclusions The evidence synthesis recommends that implementing strength training at the workplace can reduce MSD  among workers with physically dem and ing work .
In regard to workplace ergonomics , there was not enough evidence from the scientific literature to guide current practice s. Based on the scientific literature , participatory ergonomics and multifaceted workplace interventions seem to have no beneficial effect on reducing MSD among this group of workers .
Purpose This systematic review investigates the effectiveness of workplace interventions to rehabilitate musculoskeletal disorders ( MSDs ) among employees with physically dem and ing work .