Mechanisms for reducing low back pain: a mediation analysis of a multifaceted intervention in workers in elderly care.

PURPOSE: A multifaceted workplace intervention consisting of participatory ergonomics, physical training, and cognitive-behavioural training (CBT) has shown effectiveness for reducing low back pain (LBP). However, the mechanisms of action underlying these intervention components are not well understood. METHODS: This was a mediation analysis of a cluster-randomised controlled trial of a multifaceted intervention in 420 workers in elderly care. Mediation analysis was carried out via structural equation modelling. Potential mediators investigated were: fear-avoidance beliefs, perceived muscle strength, use of assistive devices at work and perceived physical exertion at work. LBP outcomes assessed were: days with LBP, LBP intensity and days with bothersome LBP. RESULTS: There were no significant indirect effects of the intervention on LBP outcomes. There were significant effects of the intervention on both fear-avoidance measures [ß = - 0.63, 95% CI (1.23, 0.03); ß = - 1.03, 95% CI (- 1.70, - 0.34)] and the use of assistive devices [ß = - 0.55, 95% CI (- 1.04, - 0.05)], but not on perceived muscle strength [ß = - 0.18, 95% CI (- 0.50, 0.13)] or physical exertion [ß = - 0.05, 95% CI (- 0.40, 0.31)]. The only potential mediator with a significant effect on LBP outcomes was physical exertion, which had a significant effect on LBP intensity [ß = 0.14, 95% CI (0.04, 0.23)]. CONCLUSIONS: A multifaceted intervention consisting of participatory ergonomics, physical training, and CBT was able to decrease fear-avoidance beliefs and increase use of assistive devices in the workplace. However, these changes did not explain the effect of any of the intervention components on days with LBP, LBP intensity and days with bothersome LBP.

Postural control and shoulder steadiness in F-16 pilots: a randomized controlled study.

BACKGROUND: During maneuvering, fighter pilots experience loads of up to 50-70 kg on their necks. Neck disorders are common and have been linked to impairment in muscle control. We conducted an intervention study introducing targeted training for 24 wk that reduced neck pain. The current study reports the results of the secondary objective, which was to increase the understanding of possible mechanisms underlying such neck pain and its intervention-related relief. METHODS: In a parallel, single-blinded, randomized controlled study, 55 F-16 pilots were evaluated at baseline and randomized to a control group (CG; N = 28) or training group (TG; N = 27). Postural control was tested in four different settings: Romberg with open and closed eyes, unilateral stance, and perturbation. Maximal voluntary contraction and force steadiness was measured for shoulder elevation. RESULTS: At follow-up, there was a significant between-group difference in the Romberg test with closed eyes only (95% confidence ellipse area; CG: 761 +/- 311 mm2; TG: 650 +/- 405 mm2). Prior to randomization, there were no significant differences in postural control and steadiness between 30 pilots who experienced neck pain within the previous 3 mo and 25 pilots without such pain. DISCUSSION: Impaired postural control and steadiness may only be quantifiable in individuals experiencing acute neck pain of certain intensity, and there may be a ceiling effect in the ability to improve these parameters. For individuals with highly developed physiological capacity, a battery of tests with more stringent demands should be considered, e.g., increased number of repetitions, prolonged duration of the tests, or testing with eyes closed.

Physical fitness as a predictor of herniated lumbar disc disease - a 33-year follow-up in the Copenhagen male study.

BACKGROUND: The role of physical fitness (VO2Max (mlO2*min-1*kg-1)) as a risk factor for herniated lumbar disc disease (HLDD) is unknown. The objective of this study was to examine the association between aerobic (physical) fitness and risk of hospitalisation due to HLDD in a long-term follow up. METHODS: The Copenhagen Male Study is a prospective cohort study established in 1970-71. At baseline, 5,249 men answered a questionnaire about their history of back disease, physical and psychosocial working conditions, lifestyle and social class. Height and weight was measured and aerobic capacity (physical fitness) was estimated based on a submaximal bicycle test. Information about hospitalization due to HLDD was obtained from the National Hospital Register covering the period 1977 - 2003. Hazard Ratios (HR) were calculated by Cox's proportional hazard regression model. RESULTS: Among 3,833 men without history of low back disorders, 64 were hospitalized due to HLDD. The cumulative incidence of HLDD was 1.7% (n=34) among men with low physical fitness (15-32 ml O2*min-1*kg-1), and 1.7% (n=30) among men with high physical fitness (33-78 ml O2*min-1*kg-1). In a final model, adjusted for relevant confounders, the HR (95% CI) for HLDD for those with high physical fitness was 0.88 (0.51-1.50) compared to those with low physical fitness. In the same model, HR for men often exposed to strenuous work compared to those seldom or never exposed to strenuous work was 3.91(1.82-8.38). Also body height was a significant predictor. CONCLUSIONS: Physical fitness is not associated with hospitalisation due to HLDD, and the only modifiable risk factor for hospitalisation due to HLDD seems to be strenuousness at work.

Effect of specific resistance training on musculoskeletal pain symptoms: dose-response relationship.

The purpose of this study was to investigate the dose-response of strength training for relieving musculoskeletal pain in female office workers. The relation between the dose of training in terms of total training volume (sets × repetitions × load reported in training diaries) during a 16-week strength training program and changes in pain (calculated as pain index, 0-100%, from self-reported intensities and durations of pain in the upper body and low back) was determined by regression analysis. The women were part of a randomized controlled trial with specific strength training (SRT), all-round physical exercise (APE), and a reference group (REF). Results showed that pain index in SRT and APE decreased significantly from baseline to follow-up (-25%/-22%) compared with changes in REF (-15%). In the dose-response analysis within the SRT group (n = 125), the total volume of training (mean 18.056 kg, SD = 13.798) was negatively correlated with changes in pain index (ß = -0.16, p = 0.045), and there was a significant dose-response relationship between training volume per session and change in pain index (ß = -0.20, p = 0.034). In contrast, training attendance (mean 1.69 sessions per week, SD = 0.8) was not significantly related to the change in pain index. In conclusion, achieving higher accumulated training volumes was important for reducing musculoskeletal pain in female office workers. The training volume per session should be optimized by securing a load at 10-15 repetition maximum and adhering to principles of progressive overload.

Does self-assessed physical capacity predict development of low back pain among health care workers? A 2-year follow-up study.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: To determine the prognostic value of self-assessed physical capacity for the development of low back pain (LBP) among female health care workers without LBP. SUMMARY OF BACKGROUND DATA: High physical capacities in terms of strength, endurance, flexibility, and balance are assumed to prevent LBP among persons with high physical work demands. However, the few existing studies investigating this relationship show contrasting findings. METHODS: Female health care workers answered a questionnaire about physical capacity in 2004, and days with LBP in 2005 and 2006. The odds ratios (ORs) for developing nonchronic (1-30 d of the past 12 mo) and persistent (>30 d of the past 12 mo) LBP in 2006 from self-assessed physical capacity were investigated with multiadjusted logistic regressions among female health care workers without LBP in 2005 (n = 1612). RESULTS: Health care workers with low and medium physical capacity had increased risk of developing nonchronic LBP (OR = 1.52 [CI = 1.05-2.20] and OR = 1.37 [CI = 1.01-1.84], respectively), and health care workers with low physical capacity had an increased risk of developing persistent LBP (OR = 2.13 [CI = 1.15-3.96]), referencing those with high physical capacity. CONCLUSION: Self-assessed low physical capacity is a strong predictor for developing nonchronic and persistent LBP among pain-free female health care workers. Future intervention studies should investigate whether increased physical capacity, for example, through exercise training prevents development of LBP among female health care workers.

The association between health and sickness absence among Danish and non-Western immigrant cleaners in Denmark.

PURPOSE: The aim of the study is to investigate the association between health and sickness absence among Danish and non-Western immigrant cleaners in Denmark. METHODS: This study is based on a cross-sectional analysis of baseline data from 2007 to 2008. The study population includes 276 cleaners, 144 Danish and 132 non-Western immigrant cleaners. Cumulative sickness absences during a 6-month period from administrative records were subdivided into no sickness absence (0 days), low occurrence of sickness absence (1-10 days) and high occurrence of sickness absence (over 10 days). Measures of health consisted of self-report and objective assessments. The relationship between sickness absence and health was analyzed through multinomial logistic regression, stratified by immigrant status. RESULTS: For both Danish and non-Western immigrant cleaners, poor self-reported health was significantly related to high occurrence of sickness absence. Among Danish cleaners, high blood pressure was related to high occurrence of sickness absence. Among non-Western immigrant cleaners, total body pain and having one or more diagnosed chronic disease were related to high occurrence of sickness absence. No association between health and low occurrence of sickness absence was found. CONCLUSIONS: The findings confirm the importance of health for high occurrence of sickness absence, in both ethnic groups. Moreover, low occurrence of sickness absence was not related to the health conditions investigated.

Effects of kettlebell training on postural coordination and jump performance: a randomized controlled trial.

The aim of this study was to investigate the effectiveness of a worksite intervention using kettlebell training to improve postural reactions to perturbation and jump performance. This single-blind randomized controlled trial involved 40 adults (n = 40) from occupations with a high prevalence of musculoskeletal pain and discomfort (mean age 44 years, body mass index 23 kg·m, 85% women). A blinded examiner took measures at baseline and follow-up. Participants were randomly assigned to a training group-doing kettlebell swings 3 times a week for 8 weeks-or to a control group. The outcome measures were postural reactions to sudden perturbation and maximal countermovement jump height. Compared with the control group, the training group had a significant decreased stopping time after perturbation (-109 ms, 95% confidence interval [-196 to -21]). Jump height increased significantly in the training group (1.5 cm, 95% confidence interval [0.5 to 2.5]), but this was nonsignificantly different from control. Kettlebell training improves postural reactions to sudden perturbation. Future studies should investigate whether kettlebell training can reduce the risk of low back injury in occupations with manual material handling or patient handling where sudden perturbations often occur.

Implementation of physical coordination training and cognitive behavioural training interventions at cleaning workplaces--secondary analyses of a randomised controlled trial.

This study evaluates the implementation of physical coordination training (PCT) and cognitive behavioural training (CBTr) interventions in a randomised controlled trial at nine cleaners' workplaces. Female cleaners (n = 294) were randomised into a PCT, a CBTr or a reference (REF) group. Both 12-week interventions were performed in groups guided by an instructor. Records were kept on intervention dose (adherence) unanticipated events at the work place (context) and quality of intervention delivery (fidelity). Participant adherence was 37% in the PCT and 49% in the CBTr interventions. Optimal implementation was reached by only 6% in PCT and 42% in the CBTr. Analysis of the barriers to successful implementation indicated that the intervention process is sensitive to unanticipated events. In order to succeed in improving the health of high-risk populations such as cleaners and to correctly interpret intervention effects, more research on implementation is needed. TRIAL REGISTRATION: ISRCTN96241850. PRACTITIONER SUMMARY: Both physical coordination training and cognitive behavioural training are potential effective workplace interventions among low educated job groups with high physical work demands. However, thorough consideration should be given to feasibility in the design of interventions. The optimal intervention should be tailored to closely match the implementation context and be robust and flexible to minimise susceptibility to changes in work organisation.

The relationship between low back pain and leisure time physical activity in a working population of cleaners--a study with weekly follow-ups for 1 year.

BACKGROUND: Low back pain (LBP) and leisure time physical activity (LTPA) are considered to be closely related, and clinical guidelines for the treatment of acute LBP recommend patients stay physically active. However, the documentation for this recommendation is sparse and based on studies involving patient populations. The purpose of the study was (1) to investigate the correlation between LBP and LTPA on a weekly basis over the course of a year in a high-risk group of cleaners; and (2) to investigate if maintaining LTPA during an episode of acute LBP has a positive effect on LBP intensity in the subsequent 4 weeks. METHODS: 188 cleaners consented to participate in a 52-week text message survey about hours of LTPA and intensity of LBP (from 0 to 9) over the previous 7 days. The correlation between LBP and LTPA was calculated by Pearson correlation coefficient. During an episode of acute LBP, a mixed effect logistic regression model was used to investigate whether cleaners who maintain LTPA have a lower pain intensity and higher probability of returning to initial pain intensity within the following four weeks compared with cleaners who decrease LTPA during acute LBP. RESULTS: The correlation between weekly LTPA and LBP data was negative, but numerically low (r = -0.069) and statistically insignificant (p = 0.08). Among the 82 cleaners experiencing at least one episode of acute LBP, those maintaining LTPA during an episode of acute LBP did not have a lower pain intensity (average LBP intensity difference between groups of 0.06; 95% confidence interval (95% CI) of -0.417 to 0.539) or higher probability of returning to initial pain level (Odds ratio 1,02; 95% CI of 0.50 to 2.09) in the following four weeks compared with cleaners decreasing LTPA during acute LBP. CONCLUSIONS: Hours of LTPA and intensity of LBP measured on a weekly basis throughout a year showed no close correlation. Maintaining LTPA during an episode of acute LBP did not result in a positive effect on LBP in the following 4 weeks. Documentation of LTPA recommendations for acute LBP in working populations is still needed.

Associations between psychosocial work environment and hypertension among non-Western immigrant and Danish cleaners.

INTRODUCTION: Non-Western cleaners have reported better psychosocial work environment but worse health compared with their Danish colleagues. The aim of this study was to compare the association between psychosocial work environment and hypertension among non-Western immigrant cleaners and Danish cleaners. METHODS: Two hundred and eighty-five cleaners from nine workplaces in Denmark participated in this cross-sectional study. The cleaners were identified as non-Western immigrants (n = 137) or Danes (n = 148). Blood pressure was measured in a seated position, and psychosocial work environment was assessed by the Copenhagen Psychosocial Questionnaire (COPSOQ). In each population, multivariate logistic regressions were applied testing for an association between each of the COPSOQ scales and hypertension. RESULTS: Models adjusted for age, sex, BMI, smoking, workplace and physical work exertion showed that high Trust regarding management (OR = 0.50) and high Predictability (OR = 0.63) were statistically significantly associated with low prevalence of hypertension in the Danish population. In the immigrant population, no significant associations were found. Analyses on interaction effects showed that associations between Meaning of work and hypertension were significantly different among the two populations (p < 0.05). CONCLUSIONS: Psychosocial work factors were associated with hypertension among Danes, but not among non-Western immigrants. This divergent association between psychosocial work environment and hypertension between Danes and non-Western immigrant cleaners may be explained by different perceptions of psychosocial work environment.

Psychosocial work environment among immigrant and Danish cleaners.

INTRODUCTION: Non-Western cleaners have been shown to have poorer health than their Danish colleagues. One reason could be a poorer psychosocial work environment. However, it is unknown if differences in self-reported psychosocial work environment exist between non-Western and Danish workers within the same social class. The aim of this study was to investigate such differences among cleaners with the hypothesis that the non-Western compared with Danish cleaners would report a generally poorer psychosocial work environment. METHODS: Two hundred and eighty-five cleaners (148 Danes and 137 non-Western immigrants) from 9 workplaces in Denmark participated in this cross-sectional study. The cleaners' immigrant status was tested for association with psychosocial work environment scales from the short version of the Copenhagen Psychosocial Questionnaire (COPSOQ) using ordinal logistic regression. RESULTS: Models adjusted for age, sex, BMI, smoking, workplace, and perceived physical work exertion showed that non-Western cleaners compared with Danish cleaners reported significantly higher scores with regard to Predictability (OR = 3.97), Recognition (OR = 1.92), Quality of Leadership (OR = 1.81), Trust Regarding Management (OR = 1.72), and Justice (OR = 2.14). CONCLUSIONS: This study showed that non-Western immigrant cleaners reported a statistically significantly better psychosocial work environment than Danish cleaners on a number of scales. Therefore, the hypothesis of non-Western immigrants reporting worse psychosocial work environment than their Danish colleagues was not supported.

Participation of Danish and immigrant cleaners in a 1-year worksite intervention preventing physical deterioration.

Worksite health promotion is seldom offered to workers who are low-educated and multi-ethnic, possibly due to an assumption that they are more reluctant to participate. Furthermore, little has been done to promote health at female-dominated workplaces. The main aim of this study was to investigate differences in participation among immigrant and Danish cleaners throughout a 1-year randomised controlled study tailored to cleaners and carried out in predominantly female workplaces. No significant differences in ethnicity were found in consent and participation throughout the 1-year intervention. Dropout was equally distributed among Danish and immigrant cleaners. This study indicates that a worksite health promotion intervention among a female-dominated, high-risk occupation such as cleaning can be equally appealing for Danes and immigrants. PRACTITIONER SUMMARY: This study provides insight about participation of Danish and immigrant cleaners in a worksite health promotion intervention in a predominantly female occupation. For attaining high participation and low dropout in future worksite health promotion interventions among cleaners, the intervention ought to not only target the ethnic background of the workers, but also to be specifically tailored to the job group.

Effects on musculoskeletal pain, work ability and sickness absence in a 1-year randomised controlled trial among cleaners.

BACKGROUND: Only a few workplace initiatives among cleaners have been reported, even though they constitute a job group in great need of health promotion. The purpose of this trial was to evaluate the effect of either physical coordination training or cognitive behavioural training on musculoskeletal pain, work ability and sickness absence among cleaners. METHODS: A cluster-randomised controlled trial was conducted among 294 female cleaners allocated to either physical coordination training (PCT), cognitive behavioural training (CBTr) or a reference group (REF). Questionnaires about musculoskeletal pain and work ability were completed at baseline and after one year's intervention. Sickness absence data were obtained from the managers' records. Analyses were performed according to the intention-to-treat-principle (ITT). RESULTS: No overall reduction in musculoskeletal pain, work ability or sickness absence from either PCT or CBTr compared with REF was found in conservative ITT analyses. However, explorative analyses revealed a treatment effect for musculoskeletal pain of the PCT. People with chronic neck/shoulder pain at baseline were more frequently non-chronic at follow-up after PCT compared with REF (p = 0.05). CONCLUSIONS: The PCT intervention appeared effective for reducing chronic neck/shoulder pain among the female cleaners. It is recommended that future interventions among similar high-risk job groups focus on the implementation aspects of the interventions to maximise outcomes more distal from the intervention such as work ability and sickness absence. TRIAL REGISTRATION: ISRCTN: ISRCTN96241850.

Neck pain and postural balance among workers with high postural demands - a cross-sectional study.

BACKGROUND: Neck pain is related to impaired postural balance among patients and is highly prevalent among workers with high postural demands, for example, cleaners. We therefore hypothesised, that cleaners with neck pain suffer from postural dysfunction. This cross-sectional study tested if cleaners with neck pain have an impaired postural balance compared with cleaners without neck pain. METHODS: Postural balance of 194 cleaners with (n = 85) and without (N = 109) neck pain was studied using three different tests. Success or failure to maintain the standing position for 30 s in unilateral stance was recorded. Participants were asked to stand on a force platform for 30 s in the Romberg position with eyes open and closed. The centre of pressure of the sway was calculated, and separated into a slow (rambling) and fast (trembling) component. Subsequently, the 95% confidence ellipse area (CEA) was calculated. Furthermore a perturbation test was performed. RESULTS: More cleaners with neck pain (81%) failed the unilateral stance compared with cleaners without neck pain (61%) (p < 0.01). However, the risk of failure in unilateral stance was statistically elevated in cleaners with concurrent neck/low back pain compared to cleaners without neck/low back pain (p < 0.01), whereas pain at only neck or only low back did not increase the risk. Impaired postural balance, measured as CEA (p < 0.01), rambling (p < 0.05) and trembling (p < 0.05) was observed among cleaners with neck pain in comparison with cleaners without neck pain in the Romberg position with eyes closed, but not with eyes open. CONCLUSIONS: Postural balance is impaired among cleaners with neck pain and the current study suggests a particular role of the slow component of postural sway. Furthermore, the unilateral stance test is a simple test to illustrate functional impairment among cleaners with concurrent neck and low back pain. TRIAL REGISTRATION: ISRCTN96241850.

Health disparities between immigrant and Danish cleaners.

PURPOSE: It is unknown whether immigrants working in the cleaning industry have a poorer health and work ability than cleaners from the native population. The main aim was to investigate differences in objective and self-reported health measures between immigrant and Danish cleaners. METHODS: Three hundred and fifty-one cleaners, consisting of 166 Danes (88% women) and 179 immigrants (74% women) (6 with unknown ethnicity), from 9 workplaces in Denmark participated in the study. Health and work ability were obtained by objective (e.g., BMI and blood pressure) and self-reported measures (e.g., work ability, self-rated health, and musculoskeletal symptoms). In order to investigate differences between Danish and immigrant cleaners, logistic regression analyses and General Linear Models were performed. RESULTS: When controlling for age, sex, workplace, job seniority, and smoking, more Danish compared with immigrant cleaners were current smokers (42% vs. 28%, p < 0.001 (not controlled for smoking)), had hypertension (46% vs. 26%, p < 0.05) and drank more alcohol (3.0 vs. 0.8 units per day, respectively, p < 0.001). Contrary, more immigrants compared with Danish cleaners were measured to be overweight (47% vs. 30%, p < 0.05), reported less than good work ability (57% vs. 42%, p < 0.01), considered it unthinkable/unsure to be able to perform work 2 years ahead (37% vs. 23%, p < 0.01), reported reduced self-rated health (46% vs. 38%, p < 0.01) and everyday pain in the neck/shoulder (28% vs. 11%, p < 0.01), wrist (18% vs. 7%, p < 0.01), and lower back (21% vs. 10%, p < 0.01). There were no differences in self-reported chronic diseases. CONCLUSIONS: Although the health of the cleaners was alarmingly poor, the immigrant cleaners generally had a poorer self-reported health and work ability than the Danish cleaners. These findings highlight the need for occupational health actions among cleaners, particularly tailored to the immigrant subpopulation.

Muscle activity during functional coordination training: implications for strength gain and rehabilitation.

The purpose of this study was to evaluate if different types, body positions, and levels of progression of functional coordination exercises can provide sufficiently high levels of muscle activity to improve strength of the neck, shoulder, and trunk muscles. Nine untrained women were familiarized with 7 functional coordination exercises 12 times during 4 weeks before testing. Surface electromyographic (EMG) activity was obtained from rectus abdominus, erector spinae, obliquus externus, and trapezius during the exercises with 2-4 levels of progression. Electromyography was normalized to the maximal EMG activity during maximal voluntary contractions, and a p value < 0.05 was considered significant. All recorded muscles reached sufficiently high levels of activity during the coordination exercises for strength gain (>60% of maximal EMG activity). Type of exercise played a significant role for the attained muscle activity. Body position during the exercises was important for the activity of the erector spinae, and level of progression was important for the activity of the trapezius. The findings indicate that depending on type, body position, and level of progression, functional coordination training can be performed with a muscle activity sufficient for strength gain. Functional coordination training may therefore be a good choice for prevention or rehabilitation of musculoskeletal pain or injury in the neck, shoulder, or trunk muscles.

Successful reach and adoption of a workplace health promotion RCT targeting a group of high-risk workers.

BACKGROUND: Cleaners are rarely introduced to workplace health promotion programs. The study's objective was to evaluate the reach and adoption of a workplace randomized controlled trial (RCT) among cleaners in Denmark. METHODS: Cleaning businesses with at least 30 employees, that could offer a weekly 1-hour intervention during working hours, were invited to participate. Employees working at least 20 hours/week were invited to answer a screening questionnaire and consent to participate. Analyses determined the differences in health variables between responders and non-responders, consenters and non-consenters, participants and non-participants and between participants of the RCT's three groups: physical coordination training, cognitive-behavioural theory-based training and reference group. RESULTS: From 16 eligible workplaces, a representative sample of 50% adopted the trial. Of 758 eligible employees, 78% responded to the screening questionnaire and 49% consented to participate. Consenters and participants differed from non-consenters and non-participants by having higher BMI, more chronic diseases and poorer musculoskeletal health. CONCLUSIONS: This study indicates that workplace health promotion programs directed at health risk factors among cleaners enable significant adoption and reach to a high-risk subgroup of the Danish workforce. TRIAL REGISTRATION: Trial registration ISRCTN96241850.

Worksite interventions for preventing physical deterioration among employees in job-groups with high physical work demands: background, design and conceptual model of FINALE.

BACKGROUND: A mismatch between individual physical capacities and physical work demands enhance the risk for musculoskeletal disorders, poor work ability and sickness absence, termed physical deterioration. However, effective intervention strategies for preventing physical deterioration in job groups with high physical demands remains to be established. This paper describes the background, design and conceptual model of the FINALE programme, a framework for health promoting interventions at 4 Danish job groups (i.e. cleaners, health-care workers, construction workers and industrial workers) characterized by high physical work demands, musculoskeletal disorders, poor work ability and sickness absence. METHODS/DESIGN: A novel approach of the FINALE programme is that the interventions, i.e. 3 randomized controlled trials (RCT) and 1 exploratory case-control study are tailored to the physical work demands, physical capacities and health profile of workers in each job-group. The RCT among cleaners, characterized by repetitive work tasks and musculoskeletal disorders, aims at making the cleaners less susceptible to musculoskeletal disorders by physical coordination training or cognitive behavioral theory based training (CBTr). Because health-care workers are reported to have high prevalence of overweight and heavy lifts, the aim of the RCT is long-term weight-loss by combined physical exercise training, CBTr and diet. Construction work, characterized by heavy lifting, pushing and pulling, the RCT aims at improving physical capacity and promoting musculoskeletal and cardiovascular health. At the industrial work-place characterized by repetitive work tasks, the intervention aims at reducing physical exertion and musculoskeletal disorders by combined physical exercise training, CBTr and participatory ergonomics. The overall aim of the FINALE programme is to improve the safety margin between individual resources (i.e. physical capacities, and cognitive and behavioral skills) and physical work demands, and thereby reduce the physical deterioration in a long term perspective by interventions tailored for each respective job-group. DISCUSSION: The FINALE programme has the potential to provide evidence-based knowledge of significant importance for public health policy and health promotion strategies for employees at high risk for physical deterioration. TRIAL REGISTRATIONS: ISRCTN96241850, NCT01015716 and NCT01007669.

The effect of worksite physical activity intervention on physical capacity, health, and productivity: a 1-year randomized controlled trial.

OBJECTIVE: To investigate the effect of two contrasting physical activity worksite interventions versus a reference intervention (REF) on various health outcomes. METHODS: A 1-year randomized controlled trial was conducted with specific resistance training (SRT), all-round physical exercise (APE), and REF. RESULTS: SRT and APE compared with REF showed significant reductions in systolic blood pressure (approximately 6 mm Hg), body fat percentage (approximately 2.2 body fat%), as well as shoulder and back pain (approximately 30% reduction in duration). Muscle strength (APE and SRT) and maximal oxygen uptake (APE) increased approximately 10%. CONCLUSIONS: Worksite intervention with both SRT as well as APE is recommended, since these activities compared with REF resulted in clinically relevant reductions of cardiovascular and metabolic syndrome-related risk factors as well as musculoskeletal pain symptoms, in combination with minor increases in physical capacity.

Rapid muscle activation and force capacity in conditions of chronic musculoskeletal pain.

BACKGROUND: The association between musculoskeletal pain and decreased maximal muscle strength capacity has been extensively studied, but knowledge about functional rapid force capacity in conditions of chronic musculoskeletal pain is lacking. The objective of this study is to investigate rapid muscle activation and force capacity of chronically painful muscles. METHODS: Cross-sectional study with 42 women with chronic trapezius myalgia, and 20 healthy matched controls. Maximal capacity was determined as peak torque and peak EMG amplitude of the painful trapezius and painfree deltoid muscles during the stable high-force phase of maximal voluntary shoulder abduction, whereas rapid capacity was determined as the steepest slope of the torque-time and EMG-time curves, defined as rate of torque development and rate of EMG rise. Intensity of pain was registered prior to the test on a visual-analogue-scale. FINDINGS: Peak torque was 18% lower at 115 degrees shoulder joint angle in women with myalgia compared with healthy controls (P<0.001), with a corresponding 29% lower level of peak EMG specifically of the painful trapezius muscle (P<0.001). Rate of torque development was 33-54% lower (P<0.001), with a corresponding 21-35% lower level of rate of EMG rise of both the painful trapezius and painfree deltoid (P<0.0001). Intensity of pain showed higher association with parameters of rapid capacity (R=-0.33 to -0.53, P<0.001-0.05) than with maximal capacity (R=-0.15 to -0.41, P<0.01-ns). INTERPRETATION: In conditions of chronic musculoskeletal pain, the ability to rapidly activate painful and painfree synergistic muscles is more severely impaired than maximal muscle activation. These findings have clinical relevance for rehabilitation of chronically painful muscles.