The Effect of an Electronic Passive Prompt Intervention on Prolonged Occupational Sitting and Light-Intensity Physical Activity in Desk-Based Adults Working from Home during COVID-19 in Ireland.

This study aimed to assess the effect of passive prompts on occupational physical behaviours (PBs) and bouts of prolonged sitting among desk-based workers in Ireland who were working from home during the COVID-19 pandemic. Electronic passive prompts were delivered every 45 min, asking participants to walk for five minutes, during working hours. Twenty-eight participants (aged 30-67 years) completed the six-week intervention between October 2020 and April 2021. PBs were measured using an activPAL3TM accelerometer, following a 24 h wear protocol, worn for the duration of the study. Participants were highly sedentary at both baseline (77.71% of work hours) and during the intervention (75.81% of work hours). However, the number of prolonged occupational sedentary bouts > 90 min was reduced compared to baseline (0.56 ± 0.08 vs. 0.77 ± 0.11, p = 0.009). Similar reductions were observed in the time spent in sustained sitting > 60 and >90 min when compared to baseline sedentary patterns (60 min: -31.27 ± 11.91 min, p = 0.014; 90 min: -27.97 ± 9.39 min, p = 0.006). Light-intensity physical activity (LIPA) significantly increased during the intervention (+14.29%, p = 0.001). This study demonstrates that passive prompts, delivered remotely, can both reduce the number and overall time spent in prolonged bouts of occupational sedentary behaviour and increase occupational LIPA.

The Acute Effects of Interrupting Prolonged Sitting Time in Adults with Standing and Light-Intensity Walking on Biomarkers of Cardiometabolic Health in Adults: A Systematic Review and Meta-analysis.

BACKGROUND: Increasing evidence highlights that accumulating sitting time in prolonged bouts is detrimental to cardiometabolic health. OBJECTIVES: This systematic review aimed to compare the effects of fractionating prolonged sitting with frequent short bouts of standing and light-intensity walking on cardiometabolic health markers and conduct a meta-analysis for differences in systolic blood pressure (SBP), postprandial glucose and insulin. METHODS: Experimental randomised crossover trials with at least three intervention arms that assessed interrupting sitting with frequent short bouts of standing and light-intensity walking over a single day compared to a prolonged sitting condition were retrieved. These studies measured at minimum one marker of cardiometabolic health in adults > 18 years. An electronic search was completed on the 2nd of August 2021, searching PubMed and Web of Science Core Collection, Scopus, Embase, Cochrane Library and APA PsycINFO. Risk of bias was assessed using a modified Downs and Black checklist. A meta-analysis was conducted using calculated Cohen's d quantifying the magnitude of difference between experimental conditions. RESULTS: Seven studies met the inclusion criteria for the systematic review. All seven studies were included within the meta-analysis for postprandial glucose, four studies were pooled for postprandial insulin and three for SBP. Biomarkers of cardiometabolic health were discussed qualitatively if fewer than three studies measured and reported the variable. A meta-analysis of seven acute, 1-day randomised crossover trials that sampled mixed-sex adults (aged > 18 years) who were predominately overweight or participants with obesity found that standing as an interruption to prolonged sitting significantly reduced postprandial glucose (∆ = - 0.31, 95% CI - 0.60, - 0.03; z = - 2.15, p < 0.04) but had no significant effect on insulin or SBP. Light-intensity walking was shown to significantly attenuate postprandial glucose (∆ = - 0.72, 95% CI - 1.03, - 0.41; z = - 4.57, p < 0.001) and insulin (∆ = - 0.83, 95% CI - 1.18, - 0.48; z = - 4.66, p < 0.001) compared to continued sitting. When comparing light-intensity walking breaks compared to standing breaks a significant reduction in glucose (∆ = - 0.30, 95% CI - 0.52, - 0.08; z = -2.64, p < 0.009) and insulin (∆ = - 0.54, 95% CI - 0.75, - 0.33; z = -4.98, p < 0.001) was observed. Both standing and light-intensity walking showed no effect on SBP. CONCLUSIONS: Frequent short interruptions of standing significantly attenuated postprandial glucose compared to prolonged sitting; however, light-intensity walking was found to represent a superior physical activity break. The feasibility and longitudinal implications of breaking sedentary behaviour with light-intensity walking should be investigated in a free-living setting. REGISTRATION: Not available.

The validity and reliability of the Achilles tendon moment arm assessed with dual-energy X-ray absorptiometry, relative to MRI and ultrasound assessments.

Dual-energy X-ray absorptiometry (DXA) in single energy mode has been shown to permit the visualisation of bone and soft tissue, such as the patellar tendon through two-dimensional sagittal imaging. However, there is no validated DXA-based measurement of the Achilles tendon moment arm (dAT). The aims of this study were: 1) to compare in vivo DXA derived measurements of the dAT at rest against two previously validated methods: tendon excursion (TE) and magnetic resonance imaging (MRI) at three ankle angles (-5°, 0° and +10°). 2) analyse the intra-day reliability of the DXA method at all ankle angles and compare between methods. Twelve healthy adults (mean ± SD: 31.4 ± 9.5 years; 174.0 ± 9.5 cm; 76.2 ± 16.6 kg) participated in this study, involving test-retest DXA scans, ultrasound scans and one MRI scan. The dAT was defined as the distance from the centre of the calcaneal-tibial joint axis to the Achilles tendon (AT) muscle-tendon line of action. DXA derived dAT measures were significantly greater than MRI measurements (19.7-24.9%) and were 45.2% significantly larger than the TE method. The test-retest reliability of the DXA technique at 0° was high [CV = 1.38%; ICC = 0.96] and despite the consistently larger dAT lengths obtained using DXA, MRI and DEXA data were strongly correlated (r = 0.878, p < 0.001). In conclusion, the DXA technique allowed for highly reproducible in vivo dAT measurement at rest, which has implications for the calculation of AT forces in vivo and the ability to predict the measurement from one tool to the other, thereby providing a novel basis to contrast existing and future studies.