Mediators and moderators of a walking intervention to prevent neck pain among high-risk office workers: a secondary analysis of a randomized controlled trial.

OBJECTIVES: To test hypothesized mediators and moderators of the benefits of an app-provided walking intervention for preventing neck pain in high-risk office workers. METHODS: Ninety-one office workers at risk for developing neck pain participated in the primary clinical trial. Two hypothesized mediators (the total number of steps taken and the number of days that participants exceed the number of recommended steps) were tested using a smartphone application every month during a 6-month period. Four hypothesized moderators (number of working hours, level of work psychological demands, chair height adjustability, and body mass index) were assessed at baseline. Parallel mediation and moderation analyses were conducted using the Hayes PROCESS macro, model 4 and 1, respectively, with post-hoc Johnson-Neyman techniques. RESULTS: The number of days that participants exceeded the recommended steps ‒ the specific number was tailored to each participant, but averaged 7735 steps/day ‒ mediated the benefits of the walking intervention for reducing the risk for neck pain at each of six assessment points (B's range -0.63 to -0.89, all p's < 0.05) over 6-month period. None of the hypothesized moderators evidenced statistically significant moderator effects of the walking intervention. CONCLUSION: Workers should walk at rates greater than recommended levels on as many days as possible, rather than attempt to maximize walking within a limited number of days. Given that the walking program studied appeared to be similarly effective across multiple groups of workers, the findings suggest that regular walking can reduce the risk for developing neck pain among high-risk office workers.

Effects of Postural Shifting Frequency on Perceived Musculoskeletal Discomfort During 1-Hour Sitting in Office Workers.

OBJECTIVE: The purpose of this study was to evaluate the effects of postural shifting frequency on perceived musculoskeletal discomfort during 1 hour of sitting in healthy office workers. METHODS: An experimental study comparing 3 different postural shifting frequencies was conducted on 60 healthy office workers who were asked to sit for an hour. The effects of 3 postural shifts (ie, 10, 20, and 30 times/h) on discomfort, measured by Borg's CR-10 scale, were compared. A seat pressure mat was used to confirm an individual's postural shift. RESULTS: Postural shifting frequency of 10 to 30 times/h had significant effects on perceived discomfort in the neck, shoulder, and upper and lower back during 1-hour sitting. At the neck and shoulder, a postural shifting frequency of 30 times/h significantly reduced perceived discomfort compared to a postural shifting frequency of 10 times/h during 1-hour sitting. At the upper and lower back, a postural shifting frequency of 20 to 30 times/h significantly reduced perceived discomfort compared to a postural shifting frequency of 10 times/h. CONCLUSION: Postural shifts of 30 times/h provided buffering effects on perceived musculoskeletal discomfort at the neck, shoulder, and upper and lower back.

Can the Borg CR-10 scale for neck and low back discomfort predict future neck and low back pain among high-risk office workers?

PURPOSE: Perceived discomfort could indicate an early sign of pain, for example, as a result of a biomechanical load on the musculoskeletal system. Assessing discomfort can, therefore, help to identify workers at increased risk of musculoskeletal disorders for targeted intervention development. We aimed: (1) to identify the optimal cut-off value of neck and low back discomfort among office workers and (2) to evaluate its predictive validity with future neck and low back pain, respectively. METHODS: At baseline healthy participants (n = 100) completed questionnaires, including the Borg CR-10 discomfort scale (on a 0-10 scale), and were followed for six months, during which musculoskeletal pain was assessed monthly. Logistic regression analyses were performed to assess the associations of baseline discomfort with the onset of future neck or low back pain. Sensitivity, specificity, and the area under the receiver operating characteristics curve were estimated to identify the optimal discomfort cut-off value predicting future pain. RESULTS: Borg CR-10 scores ≥ 3.5 for perceived neck and low back discomfort had acceptable sensitivity and specificity to predict future neck and low back pain, respectively. Perceived discomfort at baseline as a dichotomous measure (using the ≥ 3.5 cut-off) was a statistically significant predictor of future neck pain (OR = 10.33) and low back pain (OR = 11.81). CONCLUSION: We identified the optimal cut-off value of the Borg CR-10 discomfort scale to identify office workers at increased risk of developing neck and low back pain. These findings might benefit ergonomists, primary health care providers, and occupational health researchers in developing targeted interventions.

Responsiveness of the UW Concerns About Pain Scale and UW Pain-Related Self-Efficacy Scale in Individuals With Chronic Low Back Pain.

OBJECTIVES: The aim was to examine the responsiveness, presence of floor or ceiling effects, and minimal clinically important differences (MCIDs) for 2 new measures of pain-related catastrophizing and self-efficacy in individuals with chronic low back pain. METHODS: A total of 183 individuals with chronic low back pain recruited from physical therapy clinics in Thailand completed the Thai versions of the 6-item University of Washington Concerns About Pain scale (T-UW-CAP6) and 6-item University of Washington Pain-Related Self-Efficacy scale (T-UW-PRSE6) at baseline and at 4 weeks follow-up. Perceived change in low back symptom was assessed at 4 weeks using a 7-point measure of Global Perceived Effect (GPE). Responsiveness of the T-UW-CAP6 and the T-UW-PRSE6 scale scores were evaluated by computing the effect sizes and standardized response means for change over time, and examining these as a function of the GPE ratings. Floor and ceiling effects were examined by evaluating the score distributions. Scale core MCIDs were estimated by computing a half a SD and SE of measurement statistics for each scale. RESULTS: Responsiveness of the scales to pain treatment was supported by differences found in the mean change scores as a function of the treatment response categories. No significant floor or ceiling effects were found for either measure. Changes of 4.38 and 3.68 appeared to be the smallest change score perceived as clinical meaningful for the T-UW-CAP6 and T-UW-PRSE 6 scale scores, respectively. DISCUSSION: The T-UW-CAP6 and T-UW-PRSE6 demonstrated good ability to detect perceived changes over time in patients with chronic low back pain. The MCIDs values provide a benchmark for assessing individual improvement in this clinical context.

Characteristics of office workers who benefit most from interventions for preventing neck and low back pain: a moderation analysis.

Introduction: Neck and low back pain are significant health problem in sedentary office workers. Active break and postural shift interventions has been proved to reduce the incidence of new onset of both neck and low back pain. Objectives: To identify variables that moderate the effects of active breaks and postural shift interventions on the development of neck and low back pain in office workers. Methods: Using data from a 3-arm (active break, postural shift, and control group) cluster randomized controlled trial (N = 193), we evaluated the moderating effects of age, job position, education level, sex, perceived psychological work demands, number of working hours, and using a chair with lumbar support on the benefits of 2 interventions designed to prevent the development of neck and low back pain in office workers. Moderation analyses were conducted using the Hayes PROCESS macro, with post hoc Johnson-Neyman techniques and logistic regressions. Results: Significant interactions between intervention groups and 3 moderators assessed at baseline emerged. For the prevention of neck pain, the effect of the active break intervention was moderated by the number of working hours and the effect of the postural shift intervention was moderated by the level of perceived psychological work demands and the number of working hours. For the prevention of low back pain, the effect of postural shift intervention was moderated by having or not having a chair with lumbar support. Conclusions: The study findings can be used to help determine who might benefit the most from 2 treatments that can reduce the risk of developing neck and low back pain in sedentary workers and may also help us to understand the mechanisms underlying the benefits of these interventions.

The effects of active break and postural shift interventions on recovery from and recurrence of neck and low back pain in office workers: A 3-arm cluster-randomized controlled trial.

OBJECTIVES: To investigate the efficacy of active break and postural shift interventions aimed to reduce sitting discomfort on recovery duration and recurrence of neck and low back pain among high-risk office workers. METHODS: A 3-arm cluster-randomized controlled trial with 12-month follow-up was conducted in 193 healthy but high-risk office workers. Participants in the intervention groups received custom-designed apparatus to facilitate either active breaks or postural shifts to reduce sitting discomfort at work. Participants in a control group received a placebo seat pad. Incidence of neck and low back pain with pain intensity and disability level was recorded monthly. Main outcome measures were recovery time and recurrent rate of neck and low back pain. Analyses were performed using log rank test and Cox proportional hazard models. RESULTS: Median time to recovery in those receiving active break and postural shift interventions (1 month) was significantly shorter than those in the control group (2 months). Neck and low back pain recurrent rates for the active break, postural shift, and control groups were 21%, 18%, and 44%, respectively. Hazard rate (HR) ratios after adjusting for biopsychosocial factors indicated a protective effect of active break and postural shift interventions for neck and low back pain recurrence (HRadj 0.22, 95% CI 0.06-0.83 for active breaks and HRadj 0.35, 95% CI 0.16-0.77 for postural shift). CONCLUSION: Active break and postural shift interventions shortened recovery time and reduced recurrence of neck and low back pain among high-risk office workers.

Effects of an active break and postural shift intervention on preventing neck and low-back pain among high-risk office workers: a 3-arm cluster-randomized controlled trial.

OBJECTIVE: This study evaluated the effects of the promotion of active breaks and postural shifts on new onset of neck and low-back pain during a 6-month follow-up among high-risk office workers. METHODS: A 3-arm cluster-randomized controlled trial with 6-month follow-up was conducted among healthy but high-risk office workers. Participants were recruited from six organizations in Bangkok, Thailand (N=193) and randomly assigned at cluster level into active break intervention (N=47), postural shift intervention (N=46), and control (N=100) groups. Participants in the intervention groups received a custom-designed apparatus to facilitate designated active breaks and postural shifts during work. Participants in the control group received a placebo seat pad. The primary outcome measure was new onset of neck and low-back pain during 6-month follow-up. Analyses were performed using Cox proportional hazard models. RESULTS: One-hundred and eighty-six (96%) predominantly female participants were successfully followed up over six months. New onset of neck pain during the 6-month follow-up occurred in 17%, 17%, and 44% of the participants in the active break, postural shift, and control groups, respectively. For new onset of low-back pain, these percentages were 9%, 7%, and 33%, respectively. Hazard rate (HR) ratios after adjusting for biopsychosocial factors indicated a protective effect of the active break and postural shift interventions for neck pain [HRadj 0.45, 95% confidence interval (CI) 0.20-0.98 for active break and HRadj 0.41, 95% CI 0.18-0.94 for postural shift] and low-back pain (HRadj 0.34, 95% CI 0.12-0.98 for active break and HRadj 0.19, 95% CI 0.06-0.66 for postural shift). CONCLUSION: Interventions to increase either active breaks or postural shifts reduced new onset of neck and low-back pain among high-risk office workers.

Perceived musculoskeletal discomfort and its association with postural shifts during 4-h prolonged sitting in office workers.

This study examined the characteristics of perceived discomfort and postural shifts at different magnitudes during a 4-h sitting period and the association between perceived discomfort and number of postural shifts. Forty healthy participants continuously typed a standardized text passage at a computer work station for 4 h. Subjects rated perceived body discomfort using Borg's CR-10 scale in 10 body regions (i.e. neck, shoulder, elbow, wrist/hand, upper back, lower back, buttock, thigh, knee, and ankle/foot). A seat pressure mat device was used to gather seat pressure data during sitting. Postural shifts were determined by analysis of the dispersion index of both ischial tuberosities from seat pressure data. The threshold for a postural shift was set at ±10% and ±20%. Perceived discomfort in all body regions increased continuously during a 4-h sitting period. The body regions with the highest perceived discomfort were the low back, buttocks, upper back, thigh, and neck. The average (±SD) numbers of postural shifts during the 1st, 2nd, 3rd, and 4th hour of sitting were 14.8 ± 9.5, 17.8 ± 9.4, 18.2 ± 11.1, and 18.1 ± 9.8 shifts per hour for the 10% threshold, and were 4.8 ± 4.4, 6.0 ± 5.6, 7.4 ± 6.7, and 7.7 ± 6.6 shifts per hour for the 20% threshold, respectively. Prolonged sitting led to an increase in perceived musculoskeletal discomfort over time. The number of postural shifts at both magnitudes increased in the first 2 h of sitting and, in the second 2-h period of sitting, only the number of larger postural shifts (with 20% threshold) increased. The findings extend our understanding of sitting behaviors.

Seat Pressure Distribution Characteristics During 1 Hour Sitting in Office Workers With and Without Chronic Low Back Pain.

BACKGROUND: Low back pain (LBP) is a major problem for office workers. Individuals adopting poor postures during prolonged sitting have a considerably increased risk of experiencing LBP. This study aimed to investigate seat pressure distribution characteristics, i.e., average pressure, peak pressure ratio, frequency of postural shift, and body perceived discomfort (BPD), during 1 hour of sitting among office workers with and without chronic LBP. METHODS: Forty-six participants (chronic LBP = 23, control = 23) typed a standardized text passage at a computer work station for an hour. A seat pressure mat device was used to collect the seat pressure distribution data. Body discomfort was assessed using the Body Perceived Discomfort scale. RESULTS: Office workers with chronic LBP sat significantly more asymmetrically than their healthy counterparts. During 1-hour sitting, all workers appeared to assume slumped sitting postures after 20 minutes of sitting. Healthy workers had significantly more frequent postural shifts than chronic LBP workers during prolonged sitting. CONCLUSION: Different sitting characteristics between healthy and chronic LBP participants during 1 hour of sitting were found, including symmetry of sitting posture and frequency of postural shift. Further research should examine the roles of these sitting characteristics on the development of LBP.