The effect of tablet tilt angles and time on posture, muscle activity, and discomfort at the neck and shoulder in healthy young adults.

BACKGROUND: Although young adults regularly perform tablet writing, biomechanics during the tablet writing with different tilt angles has not been studied. The objective of this study was to compare posture, muscle activity, and discomfort at the neck and shoulder between tablet writing with 0° (horizontal) and 30° tablet tilt angles over 40 minutes in healthy young adults. METHODS: Twenty participants wrote continuously for 40 minutes on a tablet with both tilt angles in a randomized order. Between conditions, there was a 5-minute activity break. Differences in neck and shoulder posture, muscle activity, and discomfort between both tablet tilt angles and changes in the outcomes every 10 minutes over 40 minutes were investigated. RESULTS: With the tilted tablet, there were lower neck flexion (Z = -4.637, P<0.001), lower shoulder extension (Z = -3.734, P<0.001), and lower neck Visual Analogue Scale (VAS) (left; Z = -4.699, P<0.001 and right; Z = -3.874, P<0.001) as compared to the no tilt condition. However, the right upper trapezius muscle activity was higher in the tilted condition as compared to the no tilt one. Over 40 minutes, the neck VAS (left; χ2(4) = 30.235, P<0.001 and right; χ2(4) = 32.560, P<0.001) and heart rate variability (χ2(4) = 12.906, P = 0.012) showed notable increases after 20 minutes compared to baseline. CONCLUSION: In conclusion, adjusting the tablet tilt to 30° and limiting time spent to 20 minutes are recommended for young adults during the tablet writing to prevent neck problems.

Factors associated with reduced risk of musculoskeletal disorders among office workers: a cross-sectional study 2017 to 2020.

BACKGROUND: Prolonged sitting at work should be avoided to reduce the risks of either noncommunicable diseases (NCDs) or musculoskeletal disorders (MSDs) among office workers. A short duration of breaks in sitting every hour can reduce cardiometabolic risk factors contributing to NCDs. However, the recommendation for a break from sitting at work to reduce the risks of MSDs has not been identified. Therefore, this study aimed to determine whether breaking by changing position at work, physical activity, physical fitness, stress and sleep were associated with MSDs among office workers. METHODS: A cross-sectional study was conducted from 2017 to 2020. Participants aged 20-59 years and using a computer at work ≥ 4 days/week were recruited. Data were collected using an online self-reporting questionnaire for computer users and 5 domains of physical fitness tests. Odds ratio (OR) with 95% confidence interval (CI) and multivariate logistic regression were used for statistical analysis. RESULTS: Prevalence of MSDs was 37.9% (n = 207/545) and the most area of complaint were the neck, shoulders and back. A nonsignificant association between physical fitness and MSDs among office workers was obtained. After adjusting for age, sex, body mass index, and comorbidity, moderate-to-vigorous intensity physical activity (MVPA) ≥ 150 min/week and sitting at work ≥ 4 h/day were MSDs risk factors (OR = 1.57, 95%CI = 1.04-2.37). Frequently changing positions from sitting to standing or walking at work every hour could reduce the risks of MSDs by more than 30%. The risks of MSDs increased among office workers who commuted by staff shuttle bus and personal car and had high to severe stress and slept < 6 h/day (1.6 to 2.4 times). CONCLUSION: Our findings indicated MVPA and prolonged sitting were MSD risk factors. We recommend office workers change position from sitting to standing or walking during work every hour and sleep ≥ 6 h/day to reduce risks of MSDs.

Identifying sincerity of effort by grip strength ratio of three wrist positions in individuals with upper extremity musculoskeletal disorders.

OBJECTIVES: To evaluate whether the grip strength ratio of three wrist positions could determine sincerity of effort (SOE), by differentiating between maximal effort (ME) and submaximal effort (SE), in individuals with upper extremity musculoskeletal disorders (MSDs). METHODS: A total of 19 volunteers with unilateral upper extremity MSDs (9 males, 10 females) participated in this study. Participants performed grip strength tests in neutral, full flexion, and full extension wrist positions for both hands. In each wrist position, they exerted grip force with their ME and preferred SE for three times. RESULTS: Significant main effects of type of effort, wrist position (P < .001), and hand (P = .005) were observed. The results also showed significant interactions for type of effort × wrist position (P < .001) and wrist positions × hand (P = .001). Moreover, the grip strength ratios of neutral/flexion (N/F) and neutral/extension (N/E) between ME and SE differed significantly (P < .001). CONCLUSION: This study suggests that the N/F and N/E grip strength ratios can discriminate between ME and SE in individuals with upper extremity MSDs. Thus, this test might be applicable to use for identifying SOE in clinical setting.

The Prevalence of and Risk Factors Associated with Musculoskeletal Disorders in Thai Oil Palm Harvesting Workers: A Cross-Sectional Study.

Musculoskeletal disorders (MSDs) are common in various occupations. However, there is still limited research about the prevalence of, and risk factors associated with, MSDs among oil palm harvesting workers in Thailand. To investigate the prevalence of MSDs and risk factors associated with MSDs in Thai oil palm harvesting workers, face-to-face interviews were conducted with Thai oil palm harvesting workers in Krabi Province, Thailand, using a questionnaire. The questionnaire consisted of four sections which included information on demographic characteristics, work-related characteristics, job stress, and MSDs. A total of 334 oil palm harvesting workers participated in the current study. The prevalence of MSDs during the past 12 months was 88.0%. Lower back MSDs had the highest (59.0%) 12-month prevalence among oil palm harvesting workers, followed by shoulder (37.1%) and neck (27.2%). Factors associated with lower back MSDs included type of task, heavy lifting, and job stress. Moreover, type of task, repetitive movement, and job stress were associated with shoulder and neck MSDs. The cutters had a higher risk of having shoulder and neck MSDs, primarily due to the fact that their work involved cutting the fresh fruit bunches from high up in the trees. The collectors had more back issues due to the heavy lifting. These findings showed the need to raise awareness, and to design guidelines and interventions to prevent MSDs in oil palm harvesting workers.

The Effects of Ramp Gradients and Pushing-Pulling Techniques on Lumbar Spinal Load in Healthy Workers.

BACKGROUND: Many tasks in industrial and health care setting are involved with pushing and pulling tasks up or down on a ramp. An efficient method of moving cart which reduces the risk of low back pain should be concerned. This study aimed to investigate the effects of handling types (HTs) and slope on lumbar spinal load during moving a cart on a ramp. We conducted a 2 × 2 × 4 factorial design with three main factors: 2 HTs, 2 handling directions of moving a cart and 4 degrees of ramp slope. METHODS: Thirty healthy male workers performed 14 tasks consist of moving a cart up and down on the ramp of 0°, 10°, 15°, and 20° degrees with pushing and pulling methods. Joint angles from a 3D motion capture system combined with subject height, body weight, and hand forces were used to calculate the spinal load by the 3DSSPP program. RESULTS: Our results showed significant effect of HT, handling directions and slope on compression and shear force of the lumbar spine (p < 0.001). When the ramp gradient increased, the L4/5 compression forces increased in both pushing and pulling (p < 0.001) Shear forces increased in pulling and decreased in pushing in all tasks. At high slopes, pulling generated more compression and shear forces than that of pushing (p < 0.01). CONCLUSION: Using the appropriate technique of moving a cart on the ramp can reduce the risk of high spinal load, and the pushing is therefore recommended for moving a cart up/down on ramp gradients.

Determining Sincerity of Effort Based on Grip Strength Test in Three Wrist Positions.

BACKGROUND: Several grip strength tests are commonly used for detecting sincerity of effort. However, there is still no widely accepted standardized sincerity of effort test. Therefore, this study aimed to examine whether grip strength test in three wrist positions could distinguish between maximal and submaximal efforts. METHODS: Twenty healthy individuals (10 men and 10 women) with a mean age of 26.7 ± 3.92 years participated in this study. All participants completed two test conditions (maximal and submaximal efforts) in three wrist positions (neutral, flexion, and extension) using both hands. Each participant exerted 100% effort in the maximal effort condition and 50% effort in the submaximal effort condition. The participants performed three repetitions of the grip strength test for each session. RESULTS: The results showed that there is a significant main effect of the type of effort (p < 0.001), wrist position (p < 0.001), and hand (p = 0.028). There were also significant types of effort and wrist position interactions (p < 0.001) and effort and hand interactions (p < 0.028). The results also showed that grip strength was highest at the wrist in neutral position in both the maximal and the submaximal effort condition. Grip strength values of the three wrist positions in the maximal effort condition were noticeably greater than those in the submaximal effort condition. CONCLUSION: The findings of this study suggest that grip strength test in three wrist positions can differentiate a maximal effort from a submaximal effort. Thus, this test could potentially be used to detect sincerity of effort in clinical setting.

Break in Sedentary Behavior Reduces the Risk of Noncommunicable Diseases and Cardiometabolic Risk Factors among Workers in a Petroleum Company.

Although prolonged sitting appears as a novel risk factor related to health outcomes for all ages, its association needs to be replicated in occupational conditions. This study explored the associations between sedentary behavior and four noncommunicable diseases (NCDs) as well as two cardiometabolic risk factors (CMRFs) among workers in a petroleum company, Thailand. All workers were invited to complete the online self-report questionnaire. Sedentary behavior was measured as the amount of time sitting at work, during recreation, and while commuting. Out of 3365 workers contacted, 1133 (34%) participated. Prevalence of NCDs and CMRFs was 36% and was positively associated with sedentary behavior. After adjusting for age, BMI, and exercise, the risk of NCDs and CMRFs for sedentary office work was 40% greater compared with more active field work. Those who took a break without sitting more than twice a day and commuted by walking or cycling had less risk of NCDs and CMRFs. The total duration of sedentary behavior was 10 h/day, and two-thirds of that total was workplace sitting. This was significantly associated with NCDs and CMRFs (p < 0.001). Day-and-night rotating shiftwork was negatively associated with NCDs and CMRFs (p < 0.001). Sedentary behavior should be considered a health risk among workers. Hence, to promote a healthy lifestyle and safe workplace, organizations should encourage standing activities during break and physically active commutes, and have workers avoid prolonged sitting.

Online self-report questionnaire on computer work-related exposure (OSCWE): validity and internal consistency.

OBJECTIVE: To develop an online, self-report questionnaire on computer work-related exposure (OSCWE) and to determine the internal consistency, face and content validity of the questionnaire. MATERIAL AND METHOD: The online, self-report questionnaire was developed to determine the risk factors related to musculoskeletal disorders in computer users. It comprised five domains: personal, work-related, work environment, physical health and psychosocial factors. The questionnaire's content was validated by an occupational medical doctor and three physical therapy lecturers involved in ergonomic teaching. Twenty-five lay people examined the feasibility of computer-administered and the user-friendly language. The item correlation in each domain was analyzed by the internal consistency (Cronbach's alpha; alpha). RESULTS: The content of the questionnaire was considered congruent with the testing purposes. Eight hundred and thirty-five computer users at the PTT Exploration and Production Public Company Limited registered to the online self-report questionnaire. The internal consistency of the five domains was: personal (alpha = 0.58), work-related (alpha = 0.348), work environment (alpha = 0.72), physical health (alpha = 0.68) and psychosocial factor (alpha = 0.93). CONCLUSION: The findings suggested that the OSCWE had acceptable internal consistency for work environment and psychosocial factors. The OSCWE is available to use in population-based survey research among computer office workers.