The biomechanical benefits of active sitting.

This cross-sectional study examined the biomechanical effects of two active chairs (AC1: had the feature to pedal and slide forward on the seat pan; AC2: a multiaxial motion seat pan) compared to a traditional office chair and standing workstation. Twenty-four healthy participants worked at each of the workstations for 60-min. The following equipment was used: Motion Capture, Electromyography, Ratings of Perceived Discomfort Questionnaire, and Exit Survey. The active protocol had positive effects on the body, including increased neuromuscular activity in the gastrocnemius, increased overall movement, and a more open trunk-thigh angle. Greater discomfort in the buttocks due to the lack of seat pan contour was reported for the AC1 which identified a need for a design modification. While standing, participants' shoulders were less flexed than when sitting in any of the three seats, however, greater discomfort was reported in the lower legs after 1 h of computer work. Practitioner summary: A comparison of four different workstations was conducted to further understand the use of active workstations. Active sitting was found to have positive effects on the body, such as allowing sitters to increase movement while sitting without the high activation of muscular activity. Standing can also provide a positive break from sitting.

Adequacy of Serial Self-performed SARS-CoV-2 Rapid Antigen Detection Testing for Longitudinal Mass Screening in the Workplace.

Importance: Longitudinal mass testing using rapid antigen detection tests (RADT) for serial screening of asymptomatic persons has been proposed for preventing SARS-CoV-2 community transmission. The feasibility of this strategy relies on accurate self-testing. Objective: To quantify the adequacy of serial self-performed SARS-CoV-2 RADT testing in the workplace, in terms of the frequency of correct execution of procedural steps and accurate interpretation of the range of possible RADT results. Design, Setting, and Participants: This prospective repeated cross-sectional study was performed from July to October 2021 at businesses with at least 2 active cases of SARS-CoV-2 infection in Montreal, Canada. Participants included untrained persons in their workplace, not meeting Public Health quarantine criteria (ie, required quarantine for 10 days after a moderate-risk contact with someone infected with SARS-CoV-2). Interpretation and performance were compared between participants who received instructions provided by the manufacturer vs those who received modified instructions that were informed by the most frequent or most critical errors we observed. Data were analyzed from October to November 2021. Exposures: RADT testing using a modified quick reference guide compared with the original manufacturer's instructions. Main Outcomes and Measures: The main outcome was the difference in correctly interpreted RADT results. Secondary outcomes included difference in proportions of correctly performed procedural steps. Additional analyses, assessed among participants with 2 self-testing visits, compared the second self-test visit with the first self-test visit using the same measures. Results: Overall, 1892 tests were performed among 647 participants, of whom 278 participants (median [IQR] age, 43 [31-55] years; 156 [56.1%] men) had at least 1 self-testing visit. For self-test visit 1, significantly better accuracy in test interpretation was observed among participants using the modified quick reference guide than those using the manufacturer's instructions for reading results that were weak positive (64 of 115 participants [55.6%] vs 20 of 163 participants [12.3%]; difference, 43.3 [95% CI, 33.0-53.8] percentage points), positive (103 of 115 participants [89.6%] vs 84 of 163 participants [51.5%]; difference, 38.1 [95% CI, 28.5-47.5] percentage points), strong positive (219 of 229 participants [95.6%] vs 274 of 326 participants [84.0%]; difference, 11.6 [95% CI, 6.8-16.3] percentage points), and invalid (200 of 229 participants [87.3%] vs 252 of 326 participants [77.3%]; difference, 10.0 [95% CI, 3.8-16.3] percentage points). Use of the modified guide was associated with improvements on self-test visit 2 for results that were weak positive (difference, 15.4 [95% CI, 0.7-30.1] percentage points), positive (difference, 19.0 [95% CI, 7.2-30.9] percentage points), and invalid (difference, 8.0 [95% CI, 0.8-15.4] percentage points). For procedural steps identified as critical for test validity, adherence to procedural testing steps did not differ meaningfully according to instructions provided or reader experience. Conclusions and Relevance: In this cross-sectional study of self-performed SARS-CoV-2 RADT in an intended-use setting, a modified quick reference guide was associated with significantly improved accuracy in RADT interpretations.

Systematic on-site testing for SARS-CoV-2 infection among asymptomatic essential workers in Montréal, Canada: a prospective observational and cost-assessment study.

BACKGROUND: Essential workers are at increased risk for SARS-CoV-2 infection. We aimed to estimate the yield, acceptability and cost of systematic workplace-based testing of asymptomatic essential workers for SARS-CoV-2 infection. METHODS: From Jan. 27 to Mar. 12, 2021, we prospectively recruited non-health care essential businesses in Montréal, Canada, through email or telephone contact. Two trained mobile teams, each composed of 2 non-health care professionals, visited businesses. Consenting asymptomatic employees provided saline gargle samples under supervision. Samples were analyzed by means of reverse transcription polymerase chain reaction (RT-PCR). At businesses with outbreaks (≥ 2 participants with a positive result), we retested all participants with a negative result on initial testing. Our primary outcomes were yield (proportion of test results that were positive), acceptability (proportion of participants estimated to be present at the business who agreed to participate) and costs (including training, sample collection and analysis, and communicating results). Our secondary outcome was identification of factors associated with a positive test result on multivariable logistic regression. RESULTS: Of the 366 businesses contacted, 69 (18.8%) agreed to participate. Nineteen businesses (28%) were manufacturers or suppliers, 12 (17%) were in auto sales or repair, and 11 (16%) were in childcare; the corresponding number of employees was 1225, 242 and 113. The median number of participants per business was 13 (interquartile range [IQR] 8-22). Of an estimated 2348 employees on site, 2128 (90.6%) participated (808 [38.0%] female, median age 48 [IQR 37-57] yr). Of the 2626 tests performed, 53 (2.0%) gave a positive result. Self-reported nonwhite ethnicity (adjusted odds ratio [OR] 3.7, 95% confidence interval [CI] 1.4-9.9) and a negative SARS-CoV-2 test result before the study (adjusted OR 0.4, 95% CI 0.2-0.8) were associated with a positive test result. Five businesses were experiencing an outbreak; at these businesses, 40/917 participants (4.4%) had a positive result on the initial test. We repeated testing for employees with initially negative results at 3 of these businesses over 2-3 weeks: 8/350 participants (2.3%) had a positive result on the second test, and none had a positive result on the third and fourth tests; no employer reported new positive results after our final visit (up to Mar. 26, 2021). At the remaining 64 businesses, 1211 participants were tested once, of whom 5 (0.4%) had a positive result. The per-person RT-PCR cost was $34, and all other costs, $8.67. INTERPRETATION: On-site saline gargle sampling of essential workers for SARS-CoV-2 testing was acceptable and of modest cost, and appears most useful in the context of outbreaks. This sampling strategy should be evaluated further as a component of efforts to prevent SARS-CoV-2 transmission. PREPRINT: medRxiv - doi:10.1101/2021.05.12.21256956.

Does active sitting provide more physiological changes than traditional sitting and standing workstations?

This cross-sectional study examined the physiological effects of two active chairs (AC1: had the feature to pedal and slide forward; AC2: was a multiaxial chair) compared to a traditional office chair and standing workstation. Twenty-four healthy participants computed at each of the workstations for 60 min. The active protocol was to alternate between a pedalling/side-to-side motion and sliding forward/front-to-back motion to the sound of a metronome operating at 40 bpm. The participants' physiological effects were recorded using near-infrared spectroscopy (NIRS); electrodermal activity (EDA) and a heart rate (HR) monitor for each collection period. Statistical analysis was conducted using a repeated measures analysis of variance for within-task and between-workstation comparisons. A Tukey's post hoc analysis was calculated for significant findings. Both active chairs significantly increased oxygenated blood in the gastrocnemius and participants' heart rate and EDA (stress) levels were affected slightly by task and time. However, participants felt more "productive" sitting in the control chair than in either of the active chairs.