Association between objectively measured static standing and low back pain - a cross-sectional study among blue-collar workers

Association between commuting time and work-related low back pain with respect to sports and leisure activities in Korean workers

Long commuting times can induce work-related low back pain (LBP), which can be exacerbated by reduced sports and leisure activities. However, there is a lack of empirical research on commuting time and work-related LBP in Korea. In this study, we aimed to investigate the relationship between commuting time and work-related LBP as well as the effect of sports and leisure activities on Korean workers. We utilized data from the sixth Korean Working Conditions Survey to analyze the relationship between commuting time and work-related LBP using multivariable logistic regression. The total number of included workers was 28,202. Workers without sports and leisure activities, and long commuting times (40-59, 60-79, and ≥80 min) showed significantly higher odds ratios for work-related LBP (1.29 [95% Confidence intervals=1.12-1.49], 1.42 [1.22-1.65], and 1.96 [1.68-2.28], respectively). However, in workers with sports and leisure activities, the results were significant only for commuting times of 60-79 and ≥80 min (1.41 [1.13-1.75], 1.60 [1.28-1.99], respectively). Long commuting times were associated with work-related LBP, and engagement in sports and leisure activities was found to play a role in mitigating the impact among Korean wage workers.

Changes in Baropodometric Evaluation and Discomfort during the Workday in Assembly-Line Workers

Prolonged standing at work is associated with health risks. The appearance of lower-limb and lower-back discomfort is one of the most prevalent factors in prolonged standing workers. The aim of this research was to evaluate the effect of an eight-hour workday on foot pressure and musculoskeletal discomfort in standing workers. Thirty-six assembly-line workers (six women) were recruited to participate in a cross-sectional study to assess foot pressure and surface, foot, knee, and lower-back discomfort before and after a real workday. Baropodometry outcomes (surface and pressure) were evaluated by the pressure platform SensorMedica and musculoskeletal discomfort was evaluated by Cornell's Musculoskeletal Discomfort Questionaire. Total foot surface (p = 0.01) and foot discomfort (p = 0.03) increased significantly at the end of the workday. Prolonged standing during 8 h workday increased the foot discomfort and total foot surface in assembly-line workers. No foot pressure variable (forefoot, rearfoot, or total) was significantly modified after the workday in assembly-line workers.

Changes in Desk-Based Workers' Sitting, Standing, and Stepping Time: Short- and Longer-Term Effects on Musculoskeletal Pain

PURPOSE

Sitting at work can be associated with musculoskeletal pain, but the effect of reductions in sitting is not well understood. We examined relationships with musculoskeletal pain of changes in sitting, standing, stepping, and short and long bouts of these behaviors.

METHODS

Analyses pooled data from 224 desk workers (68.4% women; mean ± SD age = 45.5 ± 9.4 yr; body mass index = 28.1 ± 6.1 kg⋅m -2 ) in intervention trial. Device-assessed (activPAL3) sitting, standing, and stepping time and multisite musculoskeletal pain (Nordic Questionnaire; 12 body areas) were assessed at baseline, 3 months, and 12 months. Compositional data analyses in linear mixed-effects regressions examined relationships within 16 waking hours of the behaviors and their short and long bouts, with changes from baseline in acute and chronic multisite musculoskeletal pain at 3 and 12 months. Analyses were adjusted for initial group randomization and relevant covariates.

RESULTS

At 3 months, increased standing relative to changes in other compositions was significantly associated with increased multisite musculoskeletal pain (acute: β = 1.54, 95% confidence interval [CI] = 0.10 to 2.98; chronic: β = 1.49, 95% CI = 0.12 to 2.83). By contrast, increased stepping relative to changes in other compositions was significantly associated with reduced multisite musculoskeletal pain (acute: β = -1.49, 95% CI = -2.97 to -0.02; chronic: β = -1.87, 95% CI = -3.75 to -0.01). Neither sitting reduction relative to changes in other compositions nor changes in short bouts relative to long bouts of the behaviors were significantly associated with multisite musculoskeletal pain changes. At 12 months, there were no significant associations for any of the compositional changes.

CONCLUSIONS

In the short term, while increasing standing with reduced sitting time can be unfavorable, concurrently increasing stepping could potentially reduce musculoskeletal pain. In the longer term, musculoskeletal pain may not be increased by moderate reductions in sitting time through spending more time standing or stepping.

Occupational factors and low back pain: a Mendelian randomization study

Background

Low back pain (LBP) is a common condition and a leading cause of health function loss worldwide. This study assessed the impact of occupational factors on LBP using Mendelian Randomization (MR) method, controlling for confounding variables.

Methods

Based on publicly available genome-wide association studies (GWAS), two-sample univariate and multivariate MR analyses were performed to assess the causal effect of occupational factors on LBP. We used the inverse variance weighted (IVW) method and sensitivity analyses to generate the total results for the univariate MR analysis. Furthermore, we performed multivariate MR analysis to assess the direct causal association between occupational factors and LBP after accounting for potential confounding variables.

Results

The total causal effect of genetically predicted job involves heavy manual or physical work on LBP was found to be significant (IVW OR, 2.117; 95% CI, 1,288-3.479; p = 0.003). Upon adjusting for potential confounding variables, the direct effect of job involves heavy manual or physical work on LBP remained statistically significant. Similarly, the total causal effect of genetically predicted job involves mainly walking or standing on LBP was also found to be significant (IVW OR, 1.429; 95% CI, 1,035-1.975; p = 0.030). However, upon adjusting for potential confounding variables, the direct effect of job involves mainly walking or standing on LBP became insignificant. In contrast, the findings from the MR analysis indicated a lack of association between work/job satisfaction and LBP. Sensitivity analysis consistently supported these trends.

Conclusion

Our results supported a causal link between job involves heavy manual or physical work and increased risk of LBP, while finding no significant associations between prolonged walking/standing at work, job satisfaction, and LBP, providing valuable insights for the development of targeted prevention and intervention strategies for LBP.

Does a break from sitting change biomechanical outcome measures or transient pain? A laboratory-based experimental study

BACKGROUND

Sitting can induce transient low back pain (LBP) in healthy individuals. A rest from sitting should provide relief, however, the parameters of breaks (activity type, intensity, duration, and timing) are not currently known.

OBJECTIVE

The purpose of this study was to examine the effect of 2-minute walking breaks at 40-minute intervals on sitting-induced LBP.

METHODS

Thirty-two healthy participants were recruited for a within-control study: two randomly presented sessions of sitting for 2 hours with and without breaks. Outcome measures were compared between condition and pain group using a three-way ANOVA with significance atp > 0.05.

RESULTS

Walking breaks at 40-minute intervals result in significantly lower pain ratings than those taken immediately before the break for sitting-induced back pain developers. However, this relief is short lived (<10 minutes), with ratings increasing to pre-break levels once the sitting exposure resumes. There were no differences in biomechanical factors between sessions. Regardless of session type, pain developers displayed higher spine fidget frequency than non-pain developers, females sat with less spine flexion, with greater gluteal activation levels, and with their center of pressure approximately half a centimeter to the left and forward compared to males, and males had significantly greater peak pressures over a smaller area compared to females.

CONCLUSION

Walking breaks at 40-minute intervals provide significant, but temporary, relief of sitting-induced back pain for pain developers. Future work should optimize break parameters and examine the longer-term benefit of breaks, especially for individuals that are not able to tolerate sitting for extended durations.

Association between long-term static postures exposure and musculoskeletal disorders among university employees: A viewpoint of inflammatory pathways

Background

Musculoskeletal disorders (MSDs) are critical occupational and social problems. With the improvement of production mechanization and automation, and the widespread application of computers, more occupations are exposed to static postures and load. This study explored the role of inflammation in the association between static postures exposure and MSDs.

Methods

This study adopted a prospective nested case-control design in which 66 lower back MSDs cases and 66 healthy controls were selected from a cohort study of university employees. The personal information, postural load, musculoskeletal symptoms, pressure pain thresholds (PPTs), and inflammatory cytokines were collected. Logistic and linear regressions were used to investigate the association among postural load, inflammatory cytokines, and lower back MSDs. Mediation analysis was used to calculate the mediation effect.

Results

The results of logistic and linear regressions showed that postural load and inflammatory cytokines were positively associated with lower back MSDs (P < 0.05), and postural load was positively associated with inflammatory cytokines (P < 0.05). Further, mediation analysis showed that the mediation effect of postural load on the lower back MSDs through TNF-α was 0.073 (95%CI: 0.025-0.128), and the mediation effect of posture load on the lower back MSDs through IL-6 was 0.098 (95%CI: 0.041-0.179), respectively.

Conclusion

Static postures were associated with the occurrence of MSDs through inflammatory cytokines, and low-level inflammation may be a critical early event in the generation of MSDs. This study may help bridge the gap of potential mechanisms linking static postures to increased risks of MSDs, and provide new evidence for targeted protection against the global increasing MSDs.

Nonlinear analysis of postural changes related to the movement interventions during prolonged standing task

This study assessed the effects of movement-based interventions on the complexity of postural changes during prolonged standing. Twenty participants, equally distributed in gender and standing work experience (SWE), completed three simulated prolonged standing sessions: without movement (control), leg exercise and footrest. The amount and complexity of variability in the centre of pressure (COP) and lumbar curvature angle were quantified using linear and nonlinear tools. Lower leg swelling and back/leg discomfort were also monitored. Participants in the SWE group showed significantly greater postural complexity during the standing. Regular leg exercise resulted in significantly higher postural complexity and lower leg discomfort and swelling. The footrest led to significant changes in amount of COP variability. Both interventions significantly reduced back discomfort. Overall, the nonlinear analysis of postural changes provided different findings compared to linear ones, considering the standing time, interventions and standing job experience. Nonlinear results were consistent with leg discomfort and swelling. Practitioner summary: The effect of movement-based interventions on dynamics of postural alterations over prolonged standing were characterised using nonlinear techniques. The effect of standing work experience was also considered. Previous experience of standing jobs and leg movements increase the complexity of postural behaviour over standing period.

Correlation between standing posture during work and low back and lower limb pain among cleaners and caregivers of older adults

ABSTRACT Maintaining a standing posture during work has been associated with musculoskeletal symptoms. Few studies, however, assess the standing time using objective measures. Thus, this study aimed to verify whether standing time at work is associated with lower back and lower limb pain in the last seven days and last 12 months in caregivers of older adults and cleaners. This is a cross-sectional study. Standing time at work was quantified using inclinometers attached to the workers’ thigh and spine. Musculoskeletal symptoms were assessed using the Nordic Musculoskeletal Questionnaire. Data were analyzed using the point-biserial correlation coefficient (rpb) between standing time at work and the presence of musculoskeletal symptoms. The analyses were performed using the SPSS software, adopting 5% significance level. Workers spend most of their time standing still (41.3%) or walking (39.3%). The presence of symptoms in the lower back was positively correlated with standing time (rpb=0.52; p<0.05). Walking time was negatively correlated with symptoms at the hip in the last 12 months (rpb=−0.53; p<0.05) and running time with symptoms at the hip, in the last seven days, (rpb=−0.43; p<0.05) and the lower back (rpb=−0.43; p<0.05). Longer standing time was correlated with the presence of symptoms in the lower back. Meanwhile, less time walking and running were correlated with the presence of musculoskeletal symptoms in the hips and lower back.

Correlação entre a postura em pé durante o trabalho e dor na coluna lombar e nos membros inferiores em trabalhadoras da limpeza e cuidadoras de idosos

RESUMO A postura em pé durante o trabalho tem sido associada a sintomas musculoesqueléticos. Entretanto, há poucos estudos que avaliam o tempo em pé utilizando medidas objetivas. Assim, o objetivo deste estudo foi verificar se o tempo em pé no trabalho está associado com dor na coluna lombar e nos membros inferiores nos últimos sete dias e 12 meses em cuidadoras de idosos e trabalhadoras da limpeza. Trata-se de estudo transversal, em que o tempo em pé no trabalho foi quantificado por meio de inclinômetros fixados na coxa e na coluna vertebral, e os sintomas musculoesqueléticos foram avaliados por meio do Questionário Nórdico de Sintomas Osteomusculares. Os dados foram analisados por meio da correlação ponto bisserial (rpb) entre o tempo em pé no trabalho e a presença de sintomas musculoesqueléticos. As análises foram realizadas por meio do software SPSS e o nível de significância adotado foi de 5%. Verificou-se que as trabalhadoras passam a maior parte do tempo em pé paradas (41,3%) ou andando (39,3%). Houve correlação positiva entre a presença de sintoma na lombar e o tempo em pé (rpb=0,52; p<0,05) e correlação negativa entre o tempo andando e sintomas no quadril (rpb=−0,53; p<0,05) nos últimos 12 meses e o tempo correndo e sintomas no quadril (rpb=−0,43; p<0,05) e na coluna lombar (rpb=−0,43; p<0,05) nos últimos sete dias. O maior tempo em pé foi correlacionado com a presença de sintomas na lombar; enquanto o menor tempo andando e correndo foram correlacionados com a presença de sintomas no quadril e na coluna lombar.

The effect of walking and stationary work on the acute back pain, muscle activation, posture and postural control of older women

Back pain is associated with activity such as walking or assembly line work that involves upper-body movement. However, no single study has explored the effect of these tasks on back pain, spinal angles and balance in an older adult female population. This study investigated changes in back pain, postural sway, upper-, lower- and full-spine angle and EMG activation of trunk muscles following 30 minutes of walking and a modified quiet standing task. Fourteen older adult females (62 ± 11yrs) with low to moderate chronic back pain were recruited as participants. Findings demonstrated that following these activities, increased acute back pain and upper-spine flexion occur although acute back pain was not clinically significant; postural control and muscle activation remained unchanged. This suggests that walking and modified quiet standing can lead to subtle acute back pain in older females that could be due to an increased upper spinal flexion rather than muscle fatigue. Practitioner summary: Back pain and postural problems are common in older adults. Older adult female participants experienced increased back pain and greater upper-spine flexion following 30-minute walking and standing with trunk rotation, but the practical importance was less clear. However, balance was unaffected, suggesting no increase in fall risk. Abbreviations: CBP: chronic back pain; MQS: modified quiet standing; QS: quiet standing; RPE: rating of perceived exertion; TD: trapezius descendens; TT: trapezius transversalis; TA: trapezius ascendens; ESL: erector spinae longissimus; C7: seventh cervical vertebrae; T7: seventh thoracic vertebrae; T10: tenth thoracic vertebrae; T12: twelfth thoracic vertebrae; L2: second lumbar vertebrae; S2: second sacral vertebrae; AP: anterior-posterior; ML: medial-lateral; SWAYtot: total postural sway; M: mean.

Is it possible to discriminate workers with a higher prevalence of low back pain considering daily exposure time in a work-related lumbar posture? A diagnostic accuracy study

The study aimed to develop and validate a cut-off for daily postures to discriminate workers with low back pain. The self-reported episode of low back pain in the last year and during the previous week and the total spent time in occupational postures of 529 workers were used to screen workers who more likely would report low back pain. The receiver operating characteristics curve verified the ability of daily time in each posture in discriminating workers with low back pain in a training sample. Then, the chi-squared test and measurements of the diagnostic accuracy were performed in the testing sample. The daily time spent in a given posture was not able to accurately discriminate against workers with low back pain. Total time spent walking was the only daily posture that discriminated workers with low back pain in the last year in the testing sample, albeit with low accuracy. Practitioner Summary: The daily time spent in a given posture was not able to accurately distinguish workers with low back pain. Total spent time in walking presented modest diagnostic accuracy and should be interpreted cautiously. The spent time in a particular posture did not detect workers with LBP in the last week.

Standing time and daily proportion of sedentary time are associated with pain-related disability in a one month accelerometer measurement in adults with overweight or obesity

OBJECTIVES

The association between the subjective experience of pain-related disability (PRD) and device-measured physical activity (PA) and sedentary behavior (SB) in overweight and obese adults is not well known. The aim of this study was to investigate the associations of pain markers with accelerometer-measured SB duration and different intensities of PA among physically inactive middle-aged adults with overweight or obesity.

METHODS

This cross-sectional analysis included 72 subjects (27 men) with mean age of 57.9 (SD 6.7) years and mean BMI of 31.6 (SD 4.1) kg/m2. SB and standing time (ST), breaks in sedentary time, light physical activity (LPA) and moderate-to-vigorous physical activity (MVPA) were measured for four consecutive weeks (mean 25 days, SD 4) with a hip-worn triaxial accelerometer. Headache, musculoskeletal pain, back pain, and PRD were assessed by visual analog scales (VAS) and using the Oswestry disability index (ODI). RAND-36 questionnaire was applied to assess health-related quality of life. The associations were studied by linear models.

RESULTS

ST was positively and SB proportion was negatively associated with PRD when adjusted for age, sex, BMI, accelerometry duration, MVPA, pain medication use, and general health perceptions assessed by RAND-36. No associations were found between ST and back pain. SB or different PA intensities were not associated with pain experience at specific sites.

CONCLUSIONS

Longer daily ST, but not LPA or MVPA is associated with higher level of PRD. Correspondingly, higher proportion of SB is associated with lower level of PRD. This suggests that individuals with PRD prefer to stand, possibly to cope with pain. These results may highlight the importance of habitual standing behaviors in coping with experienced PRD in adults with overweight or obesity.

Occupational status and self-reported low back pain by gender: a nation-wide cross-sectional study among the general population in Japan

Background

We aimed to examine the cross-sectional association between occupational class and self-reported low back pain (LBP) in a representative sample of the Japanese general population.

Methods

We used anonymized data from a nationwide survey (31,443 men and 35,870 women aged ≥ 20). Occupational class variables included working status, occupation, employment status, and company size (number of employees). Covariates included age, socio-economic status, lifestyle, and comorbidities. Poisson regression models stratified by gender were used to estimate adjusted prevalence ratio (APR) and 95% confidence interval (CI) for self-reported LBP.

Results

The prevalence of self-reported LBP was 11.7% in men and 14.2% in women. After adjustment for covariates and mutual adjustment for all occupational class variables, among both genders, agricultural/forestry/fishery workers and non-workers had a significantly higher prevalence of self-reported LBP: APR (95% CI) of agricultural/forestry/fishery was 1.36 (1.08–1.70) in men and 1.59 (1.30–1.93) in women; that of non-workers was 1.42 (1.18–1.70) in men and 1.23 (1.08–1.40) in women. Among men, non-regular employees were more likely to have self-reported LBP than regular employees: APR (95% CI) was 1.25 (1.07–1.46) in part-timers and casual staff and 1.18 (1.03–1.35) in other types of non-regular employees. Moreover, compared to men working at companies with ≥ 100 employees, men working at companies with 30–99 employees had a significantly higher prevalence of self-reported LBP (APR 1.17; 95% CI, 1.03–1.34). Among women, professionals and technicians (1.26; 1.11–1.43) and sales workers (1.22; 1.04–1.43) had a significantly higher prevalence of self-reported LBP than clerks. Neither employment status nor company size was associated with self-reported LBP in women. After stratified analyses by age group, similar patterns were observed in participants aged 20–64, but not in those aged ≥ 65.

Conclusion

Our results suggest that self-reported LBP is highly prevalent among agricultural/forestry/fishery workers and the unemployed, regardless of gender, and that there are also gender differences in the association of occupational class factors with self-reported LBP. It is necessary, therefore, to take preventive measures against LBP based on gender and occupational class factors in Japan.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12199-021-01031-2.

Thigh-worn accelerometry for measuring movement and posture across the 24-hour cycle: a scoping review and expert statement

Introduction

The Prospective Physical Activity Sitting and Sleep consortium (ProPASS) is an international collaboration platform committed to harmonise thigh-worn accelerometry data. The aim of this paper is to (1) outline observational thigh-worn accelerometry studies and (2) summarise key strategic directions arising from the inaugural ProPASS meeting.

Methods

(1) We performed a systematic scoping review for observational studies of thigh-worn triaxial accelerometers in free-living adults (n≥100, 24 hours monitoring protocols). (2)Attendees of the inaugural ProPASS meeting were sent a survey focused on areas related to developing ProPASS: important terminology (Q1); accelerometry constructs (Q2); advantages and distinct contribution of the consortium (Q3); data pooling and harmonisation (Q4); data access and sharing (Q5 and Q6).

Results

(1) Eighty eligible articles were identified (22 primary studies; n~17 685). The accelerometers used most often were the ActivPAL3 and ActiGraph GT3X. The most commonly collected health outcomes were cardiometabolic and musculoskeletal. (2) None of the survey questions elicited the predefined 60% agreement. Survey responses recommended that ProPASS: use the term physical behaviour or movement behaviour rather than 'physical activity' for the data we are collecting (Q1); make only minor changes to ProPASS's accelerometry construct (Q2); prioritise developing standardised protocols/tools (Q4); facilitate flexible methods of data sharing and access (Q5 and Q6).

Conclusions

Thigh-worn accelerometry is an emerging method of capturing movement and posture across the 24 hours cycle. In 2020, the literature is limited to 22 primary studies from high-income western countries. This work identified ProPASS's strategic directions-indicating areas where ProPASS can most benefit the field of research: use of clear terminology, refinement of the measured construct, standardised protocols/tools and flexible data sharing.

Static Balance Modification during the Workday in Assembly Chain Workers with and without Current Low Back Pain

Background: Low back pain (LBP) is a common recurrent pathology among assembly chain workers. This population tends to spend most of the workday in a static standing posture and handling loads, with balance being essential for correct job performance. LBP is related to poorer postural control, so balance could be affected in this condition. Methods: The purpose of the present study is to analyze the deterioration of static balance generated by work activity in a prolonged standing position. We assess sway with a pressure platform at three moments of the workday (before, during, and after work), comparing the different balance parameters in 22 manufacturing plant workers with (17) and without (5) LBP. Results: In the pre-work capture, an independent t-test showed no significant differences between the pain and non-pain groups’ static balance parameters. Between the pre- and mid-workday captures, a two-way ANOVA with repeated measures showed a significant decrease in the medial-lateral center of pressure displacement with open eyes in workers with LBP. Conclusions: workers with low back pain do not show a greater deterioration in static balance than workers without pain during the workday.

Measurement Properties of the Sedentary Behavior Questionnaire in Patients with Chronic Nonspecific Low Back Pain

BACKGROUND

The Sedentary Behavior Questionnaire (SBQ) is a brief and easy instrument to measure time spent on sedentary activities; however, no study has investigated the reliability and validity of this questionnaire in people with chronic low back pain (LBP).

OBJECTIVE

To investigate the internal consistency, test-retest reliability, measurement error, construct validity, and interpretability of the SBQ against data derived from an accelerometer in patients with nonspecific chronic LBP.

STUDY DESIGN

Cross-sectional study.

SETTING

Outpatient physiotherapy clinic.

PATIENTS

Seventy-five patients aged between 18 and 60 years (mean age, 42 years old) with nonspecific chronic LBP were recruited for this study.

INTERVENTIONS

Not applicable.

METHODS

The Cronbach's α was calculated to investigate the internal consistency of the SBQ and the intraclass correlation coefficient (ICC) was calculated to investigate the reliability of the SBQ between two administrations separated by a 1-week interval. Measurement error was assessed calculating the SEM and minimal detectable change (MDC). Spearman correlation (r) was calculated to investigate the construct validity using hypothesis testing. Interpretability was investigated using ceiling and floor effects.

RESULTS

The Cronbach's α of the SBQ total score was 0.92, indicating homogeneity among the items of the instrument. The reliability of the SBQ was excellent (ICC > 0.75), without any evidence of ceiling and floor effects. Regarding measurement error, the total score of the SBQ showed an SEM and MDC of 109.8 minutes per day and 304.4 minutes per day, respectively. However, there were no correlations of the SBQ domains or the total score with the accelerometer-measured sedentary time (r < 0.25).

CONCLUSION

The SBQ is a reliable tool for quantifying time spent in sedentary activities of patients with chronic LBP. The SBQ showed poor construct validity compared to the accelerometer-measured sedentary time, which indicates that patients may underestimate their time spent in sedentary activities.

Sedentary and Physical Activity Behavior in "Blue-Collar" Workers: A Systematic Review of Accelerometer Studies

BACKGROUND

This systematic review assessed evidence on the accelerometer-measured sedentary and physical activity (PA) behavior of nonoffice workers in "blue-collar" industries.

METHODS

The databases CINAHL, Embase, MEDLINE, PubMed, and Scopus were searched up to April 6, 2018. Eligibility criteria were accelerometer-measured sedentary, sitting, and/or PA behaviors in "blue-collar" workers (≥10 participants; agricultural, construction, cleaning, manufacturing, mining, postal, or transport industries). Data on participants' characteristics, study protocols, and measured behaviors during work and/or nonwork time were extracted. Methodologic quality was assessed using a 12-item checklist.

RESULTS

Twenty studies (representing 11 data sets), all from developed world economies, met inclusion criteria. The mean quality score for selected studies was 9.5 (SD 0.8) out of a maximum of 12. Data were analyzed using a range of analytical techniques (eg, accelerometer counts or pattern recognition algorithms). "Blue-collar" workers were more sedentary and less active during nonwork compared with work time (eg, sitting 5.7 vs 3.2 h/d; moderate to vigorous PA 0.5 vs 0.7 h/d). Drivers were the most sedentary (work time 5.1 h/d; nonwork time 8.2 h/d).

CONCLUSIONS

High levels of sedentary time and insufficient PA to offset risk are health issues for "blue-collar" workers. To better inform interventions, research groups need to adopt common measurement and reporting methodologies.

Are accelerometer measures of temporal patterns of static standing associated with lower extremity pain among blue-collar workers?

BACKGROUND

Pain in the lower extremities is common among blue-collar workers, with prolonged static standing as a potential risk factor. However, little is known about the association between diurnal accelerometer measures of static standing and pain in the lower extremities, and the potential importance of temporal patterns of static standing for this association.

RESEARCH QUESTION

We aimed to investigate the cross-sectional association between accelerometer measures of total static standing time and temporal patterns (bout duration) of static standing (short: 0-5 min; moderate: >5-10 min; and long bouts: >10 min) during total day, work and leisure and pain intensity (on a 0-10 scale) in hips, knees and feet/ankles.

METHODS

Accelerometers were used to measure static standing during four consecutive days among 677 blue-collar workers. Linear regression analyses were used to investigate the association between static standing time and pain intensity in the lower extremities.

RESULTS

Total static standing time comprised, on average, 3.9 h per day. 72.6% of the workers were exposed to long bouts of static standing, averaging 0.1 h per day. Short bouts of static standing were positively associated with hip and knee pain during total day, and positively associated with knee pain during work. Also, total static standing time during leisure was positively associated with knee and hip pain. A negative, but not significant, association was found for static standing in moderate bouts at work and hip pain.

SIGNIFICANCE

Even though the associations found were weak, these findings suggest that the temporal pattern of static standing is of importance for pain in the lower extremities. Future research should examine the possibility that moderate bouts of standing could play a role in preventing lower extremity pain.