The effectiveness of a 6-month intervention with sit-stand workstation in office workers: Results from the SUFHA cluster randomized controlled trial.

BACKGROUND: Prolonged periods of sitting have been linked to negative health outcomes. Implementation of sit-stand desks in the workplace has been one strategy to reduce prolonged sitting. OBJECTIVE: To assess the effectiveness of sit-stand workstations on reducing sitting time and improving other health outcomes of office-based workers. METHODS: 39 Portuguese office workers were randomized into a 6-month parallel-group cluster RCT consisting by the implementation of sit-stand desks in the workplace. The primary outcome of sitting time was assessed using ActivPAL. Secondary outcomes included biometric, psychological, and diet-related variables. All outcomes were assessed at baseline and 6 months for the whole sample and at 3 months for a sub-sample of the intervention group (n = 11). RESULTS: No significant time*group interaction was found for the primary or secondary outcomes, apart from waist circumference favoring the control group (Δ-1.81 cm, pinteraction = 0.04). There were significant changes within the intervention group for sitting time (-44.0 min/day), prolonged sitting (>30 min) (-45.3 min/day) and standing time (51.7 min/day) at 3 months in the sub-sample and in prolonged sitting (>30 min) (-26 min/day) in the full intervention group (p < 0.05). Changes were also observed within the intervention group for percent body fat (Δ-3.7%) and ratings of quality of life (Δ2.2), musculoskeletal discomfort (Δ-4.9), overall fatigue (Δ-2.2), and the need for recovery after work (Δ-1.7) at 6-month follow-up (p < 0.05). CONCLUSION: Although not being effective for reducing sitting time, the implementation of sit-stand desks in the Portuguese workspace was shown to be feasible over the long term, received well by users, and may offer other health benefits. TRIAL REGISTRATION: OSF Registration, OSF.IO/JHGPW. Registered 15 November 2022. https://doi.org/10.17605/OSF.IO/JHGPW.

Home-based exercise interventions' impact on breast cancer survivors' functional performance: a systematic review.

INTRODUCTION: Home-based exercise (HBE) programs can be a feasible strategy to enhance functional performance and promote physical activity (PA) in breast cancer survivors. A deeper analysis of the effects of HBE interventions, structured by HBE program type and treatment phase, is needed. This systematic review aimed to synthesize the evidence on HBE interventions' impact on breast cancer survivors' functional performance, PA levels, and program adherence rates, according to HBE intervention type and treatment phase. METHODS: A comprehensive search of peer-reviewed articles reporting HBE interventions' effects on the outcomes of interest was performed in Pubmed, Google Scholar, EBSCO, Web of Science, Science Direct, and B-ON until January 15th, 2024. Data were synthesized according to Denton's domains to classify HBE interventions (prescription: structured vs. unstructured; Delivery method: supervised vs. facilitated vs. unsupervised) and treatment phase. Methodological quality appraisal was performed using the Effective Public Health Practice Project tool. RESULTS: Twenty-six studies were included. Most studies conducted structured/facilitated interventions and reported positive effects on functional performance (particularly aerobic capacity), increases in PA levels, and high adherence rates (> 70%) during and post-treatment. CONCLUSION: HBE interventions may be feasible to improve functional performance and promote physical activity among breast cancer survivors. Further studies are needed to confirm which HBE intervention type is more appropriate for each treatment phase. More evidence applying HBE interventions with different designs is required to allow the drawing of more solid conclusions. Studies exploring the effects of HBE interventions on the pre-treatment phase are needed.

Different sedentary behavior domains present distinct associations with eating-related indicators.

BACKGROUND: Unhealthful dietary patterns have been consistently associated with low levels of physical activity (PA), but studies dedicated to sedentary behavior (SB) are scarce, especially in adults. The few studies that investigated the association between SB and dietary patterns focused mostly on specific types of SB, such as TV-watching or screen time. SB can be accumulated in distinct domains (i.e., work, transport, and leisure-time), thus, it is key to investigate in depth the impact that different domains of SB can have on eating-related indicators. We aimed to investigate the associations between different SB domains and eating-related indicators, in a sample of adults. METHODS: Cross-sectional data from students, teachers, and staff from a Portuguese University was collected in November/2021 through an anonymous online survey. Data analyses were performed using the IBM SPSS software (version 28.0) and included descriptive statistics, partial correlations, and group comparisons using one-way ANOVA. Daily average SB at work/study, transport, and in leisure-time were self-reported and eating-related indicators were measured with several items from the Mediterranean Diet Score. Specific eating-related behaviors reflecting a protective eating pattern (e.g., eating breakfast regularly), and eating behavior traits (e.g., external eating) were also assessed. Body mass index (BMI) was calculated as weight (kg)/height(m)2. The International Physical Activity Questionnaire/Short-Form was used to assess PA. RESULTS: The sample included 301 adults (60.1% women), with a mean age of 34.5 years. Overall, leisure-time SB was inversely associated with adherence to the Mediterranean diet (r = -0.20; p < 0.001) and with a protective eating profile (r = -0.31; p < 0.001). Higher transport SB was also related to lower adherence to the Mediterranean diet (r = -0.20; p < 0.001) and to an unhealthier eating profile (r = -0.22; p < 0.001), but no associations were found for work-related SB (p > 0.05). These results persisted after the adjustment for BMI, sex, and self-reported PA. These results were impacted by the age tertile. CONCLUSIONS: Our findings suggest that adults with higher levels of SB in leisure-time and transport domains tend to report less healthy eating-related behaviors, irrespective of BMI, sex, and PA level. However, some differences in these associations were found according to the age tertile. This information may assist public health authorities in focusing their efforts in augmenting literacy on SB, namely on how SB can be accumulated via different settings. Furthermore, public health literacy efforts need to extend besides the more known deleterious effects of SB on health (e.g., diabetes, cardiovascular disease), to also include the interplay with eating indicators. Strategies to reduce SB and unhealthy eating should be particularly focused on promoting physically active forms of commuting and reducing SB in the leisure setting.

COVID-19 Social Restrictions' Impact on the Health-Related Physical Fitness of the Police Cadets.

We aim to examine the changes in health-related physical fitness components, before and after COVID-19 social restrictions, in Police Academy cadets by age, sex, and physical activity (PA) level. A longitudinal analysis of 156 cadets (29.5% women) aged 25.4 ± 5.3 years old was conducted. All variables were collected before and after the lockdown period (13 weeks). PA levels were assessed with a self-reported questionnaire. Health-related physical fitness components were assessed based on the standardized protocols of morphological evaluation, speed, agility, strength, flexibility, and aerobic capacity tests. Despite the high correlations between pre- and post-pandemic social restrictions, we found significantly higher values for anthropometric indicators and lower physical fitness levels in post-pandemic restrictions, except for lower-body strength. When stratifying the sample by sex, age, and PA categories, the results indicate that the COVID-19 lockdown tends to differently impact anthropometric indicators and the physical fitness of the cadets, according to their sex, age, and PA categories. Our findings show that our sample reduces several health-related physical fitness components due to the social lockdown, with emphasis on cardiorespiratory fitness in men and upper-limb strength in women, highlighting the need to create effective strategies to keep police officers active during situations of less physical work.

Providing office workers with height-adjustable workstation to reduce and interrupt workplace sitting time: protocol for the Stand Up for Healthy Aging (SUFHA) cluster randomized controlled trial.

BACKGROUND: Sedentary behavior (SB) has been linked to several negative health outcomes. Therefore, reducing SB or breaking up prolonged periods of SB improves functional fitness, food consumption, job satisfaction, and productivity. Reducing SB can be achieved by introducing a health-enhancing contextual modification promoted by a sit-stand desk in the workplace. The primary goal will be to test the effectiveness of this intervention in reducing and breaking up SB, while improving health outcomes in office-based workers during a 6-month intervention. METHODS: A two-arm (1:1), superiority parallel-group cluster RCT will be conducted to evaluate the effectiveness of this intervention in a sample of office-based workers from a university in Portugal. The intervention will consist of a psychoeducation session, motivational prompts, and contextual modification promoted by a sit-stand desk in the workplace for 6 months. The control group will work as usual in their workplace, with no contextual change or prompts during the 6-month intervention. Three assessment points will be conducted in both groups, pre-intervention (baseline), post-intervention, and a 3-month follow-up. The primary outcomes include sedentary and physical activity-related variables, which will be objectively assessed with 24 h monitoring using the ActivPAL for 7 days. The secondary outcomes include (a) biometric indices as body composition, body mass index, waist circumference, and postural inequalities; and (b) psychosocial variables such as overall and work-related fatigue, overall discomfort, life/work satisfaction, quality of life, and eating behavior. Both the primary and secondary outcomes will be assessed at each assessment point. DISCUSSION: This study will lean on the use of a sit-stand workstation for 6 months, prompted by an initial psychoeducational session and ongoing motivational prompts. We will aim to contribute to this topic by providing robust data on alternating sitting and standing postures in the workplace. TRIAL REGISTRATION: The trial was prospectively registered, and the details are at: https://doi.org/10.17605/OSF.IO/JHGPW ; Registered 15 November 2022. OSF Preregistration.

Compensatory mechanisms from different exercise intensities in type 2 diabetes: a secondary analysis of a 1-year randomized controlled trial.

AIMS: This investigation aimed to determine the effect of different intensities of training on non-exercise physical activity (NEPA) and estimated thermogenesis (NEAT) from a 1-year exercise randomized controlled trial (RCT) in individuals with type 2 diabetes mellitus (T2DM) on non-training days. Additionally, changes in NEPA and estimated NEAT in those who failed (low-responders) or succeeded (high-responders) in attaining exercise-derived clinically meaningful reductions in body weight (BW) and fat mass (FM) (i.e., 6% for FM and 3% for BW) was assessed. METHODS: Individuals with T2DM (n = 80) were enrolled in a RCT with three groups: resistance training combined with moderate-intensity continuous training (MICT) or high-intensity interval training (HIIT) and a control group. Of the 80 participants, 56 (completed data) were considered for this secondary analysis. NEPA and estimated NEAT were obtained by accelerometry and body composition through dual-energy X-ray absorptiometry. RESULTS: After adjustments, no time*group interactions were found for estimated NEAT in the MICT (ß = - 5.33, p = 0.366) and HIIT (ß = - 5.70, p = 0.283), as well as for NEPA in the MICT (ß = - 452.83, p = 0.833) and HIIT (ß = - 2770.76, p = 0.201), when compared to controls. No compensatory changes in NEPA and estimated NEAT were observed when considering both low-responders and high-responders to FM and BW when compared to controls. CONCLUSIONS: Both MICT and HIIT did not result in any compensatory changes in estimated NEAT and NEPA with the intervention on non-training days. Moreover, no changes in estimated NEAT and NEPA were found when categorizing our participants as low-responders and high-responders to FM and BW when compared to controls. Trial registration clinicaltrials.gov ID. NCT03144505.

Discrepancies Between Self-reported and Objectively Measured Smartphone Screen Time: Before and During Lockdown.

Screen time shows higher health risks compared to other types of sedentary behaviors. A lockdown may simultaneously increase screen time, reduce physical activity (PA), and change time perception. Our goal was to compare self-reported against objectively measured smartphone screen time (SST) in a sample of active and inactive Portuguese adults before and during a social lockdown. This study was a cross-sectional analysis with 211 Portuguese adults (57.8% males), aged 25.2 ± 8.5 years, from two cohorts, one before the social lockdown and the other during the lockdown. SST was self-reported (SR-SST) and objectively measured using a smartphone (OM-SST). PA was self-reported. Linear regressions were performed to determine the association between SR-SST and OM-SST. A Bland and Altman analysis was used to assess agreement. Independent T-tests were performed for comparisons between cohorts and paired sample T-tests for comparisons within each cohort. The cohort assessed during the lockdown showed a higher SST than the cohort assessed before the lockdown (OM-SST; p < 0.001 and SR-SST; p = 0.009). Before the lockdown, there was no difference between SR-SST and OM-SST (p = 0.100). However, during the social lockdown, although the agreement between SR-SST and OM-SST was good (ICC = 0.72), participants systematically underestimated their SST by ~ 71 min/day (p < 0.001), and this underestimation was higher in inactive participants (~ 85 min/day) than in active individuals (~ 49 min/day). The general population needs to be aware of the benefits of limiting screen time, especially during periods of societal modifications, such as a generalized lockdown. There was a tendency to underestimate SST, meaning a lack of awareness of the actual time spent in this potentially deleterious behavior. This underestimation was more pronounced during the lockdown period and for the inactive participants, thus posing a greater health risk. The findings from this investigation entail relevant information for policy makers to delineate strategies for reducing population screen time from a preventive health perspective.

Breaking-Up Sedentary Behavior and Detraining Effects on Glycemic Control: A Randomized Crossover Trial in Trained Older Adults.

In a randomized crossover trial, we examined the effects of interrupting sedentary behavior on glycemic control in trained older adults, before and after 2 weeks of detraining. Fourteen participants (65-90 years old) completed two 7-hr conditions before and after 2 weeks of detraining: (a) uninterrupted sitting (SIT) and (b) sitting plus 2 min of moderate-intensity activity every 30 min (INT). Both before and after detraining, no differences were observed for 7-hr glucose area under the curve (7 hr AUC) and mean glucose between sitting plus 2 min of moderate-intensity activity and uninterrupted sitting conditions. After detraining and for the SIT condition, higher values of 7-hr AUC (p = .014) and mean glucose (p = .015) were observed, indicating worsened glycemic control. No changes were observed in INT condition between both time points. Frequent interruptions in sedentary behavior had no effect on glycemic control, prior to or after detraining. Even so, older adults experiencing a short-term detraining period should avoid prolonged bouts of sedentary behavior that may jeopardize their glycemic control.

A hierarchy of correlates for objectively measured physical activity, sedentary time, and physical fitness in older adults: A CHAID analysis.

The aging process reflects, in many cases, not only a decline in physical activity (PA) and physical fitness (PF), but also an increase in overall levels of sedentary time (ST). In order to hierarchically identify the most powerful correlates related to low and high levels of objectively assessed PA, ST, and PF during the late adulthood, a total of 2666 older adults were cross-sectionally evaluated. Multidimensional correlates were obtained through interview. Using chi-squared automatic detection analysis to identify the cluster of correlates with most impact on PA (<21.4 min/day), ST (≥8 h/day), and PF (<33.3th percentile), was found that the most likely subgroup to be physically inactive consisted of widowers not owning a computer and sport facilities in the neighbourhood (94.7%), while not being widowed, reporting to have a family that exercises and a computer at home (54.3%) represented the subgroup less likely to be inactive. Widowers without sidewalks in the neighbourhood were the most sedentary group (91.0%), while being a married woman and reporting to have space to exercise at home (40%) formed the most favourable group of correlates regarding ST. Men reporting a financial income <500€ and physical problems frequently formed the group with the lowest PF level (70.3%). In contrast, the less likely subgroup to have low levels of PF level consisted of having a financial income ≥1000€ and a computer at home (3.4%). Future interventions should target widowers with limited accessibility to computer and urban/sport-related infrastructures, as well as impaired older adults with low financial income.HighlightsChi-squared automatic interaction detection was used to identify and hierarchise correlates of objectively measured physical activity, sedentary time, and fitness.Widowers not having a computer at home and sport facilities in the neighbourhood were the most likely to be physically inactive, while not being widowed, having a family that exercises and a computer at home represented the subgroup less likely to be physically inactive.The most likely to be classified as sedentary were widowers without sidewalks in the neighbourhood, while the most favourable group of correlates regarding ST was formed by married women and reporting to have space to exercise at home.Individuals with a low financial income and physical problems comprised the population subgroup with the lowest PF levels, while having a medium-high financial income and a computer at home represented the less likely subgroup to have low levels of PF.

Effect of a 16-week multi-level classroom standing desk intervention on cognitive performance and academic achievement in adolescents.

The replacement of traditional classroom desks for active-permissive desks has been tested to reduce sitting time during classes. However, their impact on other domains is still unclear. We aimed to verify the potential effects of a classroom standing desk intervention on cognitive function and academic achievement in 6th-grade students. This was a controlled trial conducted with two classes [intervention (n = 22) and control (n = 27)] from a public school in Lisbon, Portugal. The intervention was carried out for 16 weeks and consisted of multi-level actions (students, parents, and teachers) centered on the implementation of standing desks in the intervention classroom. The control group had traditional classes with no use of standing desks or any other interference/action from the research team. Pre- and post-assessments of executive functions (attention, inhibitory function, memory, and fluid intelligence) and academic achievement were obtained. No differences between groups were found at baseline. Both groups improved (time effect) academic achievement (p < 0.001), memory span (p < 0.001), and inhibitory function (p = 0.008). Group versus time interactions were observed regarding operational memory (intervention: + 18.0% and control: + 41.6%; p = 0.039) and non-verbal fluid intelligence (intervention: - 14.0% and control: + 3.9%; p = 0.017). We concluded that a 16-week classroom standing desk intervention did not improve cognitive performance or academic achievement more than the traditional sitting classes.Trial registration: ClinicalTrials.gov Identifier (NCT03137836) (date of first registration: 03/05/2017).

Sedentary behaviours and their relationship with body composition of athletes.

ABSTRACTDuring the recovery period, athletes present high sedentary behaviour (SB). In non-athletes, there is a direct relationship between SB and obesity. However, little is known about this relationship in athletes. We hypothesized that different types of SB entail different associations with body composition outcomes.We examined the associations between different types of SB and body composition outcomes in 135 athletes (70 males) aged 21.3 ± 3.9 years old. Dual-energy X-ray absorptiometry was performed to assess fat mass (FM), fat-free mass (FFM) and trunk fat mass (TFM). A validated SB questionnaire (PACE) was used to estimate total SB and specific sedentary pursuits on an average day. Multiple linear regression analyses were performed, adjusting for age, sex, weekly training time, years of sport practice, and sport type.A positive association was found for total SB and total screen time with %TFM (ß = 0.220, p = 0.038 and ß = 0.319, p = 0.040, respectively), while an inverse association was found for %FFM (ß = -0.214, p = 0.042 and ß = -0.310, p = 0.026). A higher total screen time was related with a higher %FM (ß = 0.283, p = 0.035). With a much stronger effect size, cell phone screen time was positively related with %FM (ß = 1.447, p = 0.001).There is still debate whether high levels of physical activity can fully counteract the harms of SB. These findings suggest that SB, particularly cell phone screen time, can compromise athletes' body composition, regardless of weekly training time. Sport federations and coaches may improve athletes' body composition by targeting specific sedentary pursuits, i.e. total screen time and cell phone screen time, during athletes' recovery time.Highlights Even in athletes, SB can compromise total and regional body composition regardless of high training time.Screen time, specifically cell phone screen time seems to be the sedentary pursuit to target in athletes.Sport federations and coaches must control SB during athletes' recovery time.

Physical fitness tests as an indicator of potential athletes in a large sample of youth.

BACKGROUND: Promoting youth sports participation is an excellent strategy to improve health and high-level sports competition around the world. AIMS: The aim of this study was to analyse the potential of commonly used physical-fitness (PF) tests to discriminate against athletes from non-athletes in young populations. MATERIAL AND METHODS: One thousand eight hundred and thirty-one youth people were analysed (boys: 514 non-athletes and 401 athletes; girls: 722 non-athletes and 194 athletes) aged 10-18 years (y). Cardiorespiratory fitness (CRF), muscular fitness (MF), agility and speed were tested using PF tests. RESULTS: Application of receiver operating characteristics curves was used to assess the discriminatory potential of each PF for distinguishing athletes from non-athletes, with an area under the curve (AUC) higher than 65% (0.65). In the oldest groups (≥16 y), the speed test at 20 m in boys (AUC = 0.70) and horizontal jump test in girls (AUC = 0.75) were the best discriminators, while the push-up-test (AUC 10-11 y boys = 0.68, AUC 14-15 y boys = 0.68, AUC 10-11 y girls = 0.73, AUC 12-13 y girls = 0.87) and the PACER (AUC boys: 12-13 y = 0.68 and AUC girls 14-15 y = 0.73) appeared to be better discriminators than other PF tests, for the younger age-groups. CONCLUSION: The speed-test at 20 m and the horizontal-jump were the best PF to identify older adolescents with athletic potential, while the PACER and push-up tests were the most discriminatory for the younger adolescents.

Interindividual Variability in Fat Mass Response to a 1-Year Randomized Controlled Trial With Different Exercise Intensities in Type 2 Diabetes: Implications on Glycemic Control and Vascular Function.

Purpose: Little is known about the interindividual variability in fat mass (FM) loss in response to high-intensity interval training (HIIT) and moderate continuous training (MCT) in individuals with type 2 diabetes mellitus (T2DM). Moreover, the impact on health-related outcomes in those who fail to reduce FM is still unclear. The aims of this investigation were (1) to assess if the individuals with T2DM who FM differed across MCT, HIIT, and control groups over a 1-year intervention and (2) to assess the changes on glycemic control and vascular function in the exercising patients who failed to lose FM. Methods: Adults with T2DM were randomized into a 1-year intervention involving a control group (n=22), MCT with resistance training (RT; n=21), and HIIT with RT (n=19). FM was assessed using dual-energy X-ray absorptiometry and a change in total body FM above the typical error was used to categorize FM responders. Glycemic control and vascular stiffness and structure were assessed. A chi-square test and generalized estimating equations were used to model the outcomes. Results: Both MCT (n=10) and HIIT (n=10) had a similar proportion of individuals who were categorized as high responders for FM, with the percent change in FM on average -5.0±9.6% for the MCT and -6.0±12.1% for the HIIT, which differed from the control group (0.2±7.6%) after a 1-year intervention (p<0.05). A time-by-group interaction for carotid artery intima-media thickness (cIMT) (p for interaction=0.042) and lower-limb pulse wave velocity (LL PWV; p for interaction=0.010) between those categorized as low FM responders and the control group. However, an interaction was observed between the high responders for FM loss and controls for both brachial and carotid hemodynamic indices, as well as in cIMT, carotid distensibility coefficient, carotid beta index, and LL PWV (p for interactions <0.05). No interactions were found for glycaemic indices (p for interaction >0.05). Conclusion: Our results suggest that the number of FM responders did not differ between the MCT or HIIT, compared to the control, following a 1-year exercise intervention in individuals with T2DM. However, low responders to FM may still derive reductions in arterial stiffness and structure. Clinical Trial Registration: Comparing Moderate and High-intensity Interval Training Protocols on Biomarkers in Type 2 Diabetes Patients (D2FIT study) - number: NCT03144505 (https://clinicaltrials.gov/ct2/show/NCT03144505).

A hierarchy of correlates impacting adults' sensor-based physical activity and sedentary time.

Investigation into correlates across all levels of the socio-ecological model predictive of objectively measured physical activity has rarely been assessed in adults. While considering a diversity of correlates, we determined which correlates best predict sensor-based moderate-to-vigorous physical activity (MVPA) and sedentary-time (ST) in adults. A Chi-squared Automatic Interaction Detection algorithm was used to hierarchize the correlates associated with high ST (≥66.6thpercentile) and sufficient MVPA (≥150 min/week) in 865 adults. The main correlate predictive of being active was currently partaking in sport/exercise. The following relevant correlates were being male for the exercisers and having trees in the neighbourhood for the non-exercisers. The final correlate to boost male exercisers' MVPA was having lots of shops in the neighbourhood and not having television in the bedroom for women. The primary correlate for high ST was job activity level, with individuals having highly active jobs being less likely to exhibit high levels of ST; being single, male, and a former athlete also increased the chances of being highly sedentary. To increase adults' MVPA, promotion of sport participation, neighbourhood landscape planning, shop availability, as well as limiting television in the bedroom must be prioritized. For counteracting ST, increasing workplace activity level is warranted.

Relative sit-to-stand power: aging trajectories, functionally relevant cut-off points, and normative data in a large European cohort.

BACKGROUND: A validated, standardized, and feasible test to assess muscle power in older adults has recently been reported: the sit-to-stand (STS) muscle power test. This investigation aimed to assess the relationship between relative STS power and age and to provide normative data, cut-off points, and minimal clinically important differences (MCID) for STS power measures in older women and men. METHODS: A total of 9320 older adults (6161 women and 3159 men) aged 60-103 years and 586 young and middle-aged adults (318 women and 268 men) aged 20-60 years were included in this cross-sectional study. Relative (normalized to body mass), allometric (normalized to height squared), and specific (normalized to legs muscle mass) muscle power values were assessed by the 30 s STS power test. Body composition was evaluated by dual energy X-ray absorptiometry and bioelectrical impedance analysis, and legs skeletal muscle index (SMI; normalized to height squared) was calculated. Habitual and maximal gait speed, timed up-and-go test, and 6 min walking distance were collected as physical performance measures, and participants were classified into two groups: well-functioning and mobility-limited older adults. RESULTS: Relative STS power was found to decrease between 30-50 years (-0.05 W·kg-1 ·year-1 ; P > 0.05), 50-80 years (-0.10 to -0.13 W·kg-1 ·year-1 ; P < 0.001), and above 80 years (-0.07 to -0.08 W·kg-1 ·year-1 ; P < 0.001). A total of 1129 older women (18%) and 510 older men (16%) presented mobility limitations. Mobility-limited older adults were older and exhibited lower relative, allometric, and specific power; higher body mass index (BMI) and legs SMI (both only in women); and lower legs SMI (only in men) than their well-functioning counterparts (all P < 0.05). Normative data and cut-off points for relative, allometric, and specific STS power and for BMI and legs SMI were reported. Low relative STS power occurred below 2.1 W·kg-1 in women (area under the curve, AUC, [95% confidence interval, CI] = 0.85 [0.84-0.87]) and below 2.6 W·kg-1 in men (AUC [95% CI] = 0.89 [0.87-0.91]). The age-adjusted odds ratios [95% CI] for mobility limitations in older women and men with low relative STS power were 10.6 [9.0-12.6] and 14.1 [10.9-18.2], respectively. MCID values for relative STS power were 0.33 W·kg-1 in women and 0.42 W·kg-1 in men. CONCLUSIONS: Relative STS power decreased significantly after the age of 50 years and was negatively and strongly associated with mobility limitations. Our study provides normative data, functionally relevant cut-off points, and MCID values for STS power for their use in daily clinical practice.

Threshold of Relative Muscle Power Required to Rise from a Chair and Mobility Limitations and Disability in Older Adults.

PURPOSE: Being able to rise from a chair is paramount for independent living and is strongly influenced by the ability of the lower limbs to exert mechanical power. This study assessed minimal thresholds of lower-limb relative muscle power required to perform the sit-to-stand (STS) task in older adults and its association with mobility limitations and disability. METHODS: A total of 11,583 older adults (age, 60-103 yr) participated in this investigation. The 5-rep and 30-s versions of the STS test were used to assess chair rising ability. Relative power was calculated by the STS muscle power test. The minimum thresholds of power required to perform the STS tests were derived from the minimum values (i.e., "floor" effect) reported in the power tests through regression analyses. Mobility limitations and disability in activities of daily living (ADL) were recorded. RESULTS: For the average older man and woman, the thresholds to complete five STS repetitions were 1.1 and 1.0 W·kg-1, respectively, whereas the thresholds to complete one STS repetition were 0.3 W·kg-1 in both sexes. These thresholds increased linearly with height (5- and 1-rep, respectively: +0.13 and +0.03 W·kg-1 per 10-cm increase; both P < 0.001) and did not differ by sex or testing condition (both P ≥ 0.259). All participants with relative power below the 5-rep threshold presented mobility limitations, and 51%-56% of women and 36%-49% of men also showed disability in ADL (all χ2 ≥ 290.4; P < 0.001). CONCLUSION: A minimum level of relative muscle power is required to rise from a chair independently, which depends on the individual height and is associated with increased mobility limitations and disability. This information will help interpret data yielded by the STS muscle power test and may contribute to the prevention and treatment of mobility limitations in older people.

Criterion validity of a single-item question for assessment of daily breaks in sedentary time in adults.

BACKGROUND: As the implementation of sensor-based assessment for sedentary time (ST) and physical activity (PA) has practical limitations when applied on a large-scale, most studies rely on subjective data. We aimed to examine the criterion validity of a single-item question to assess daily breaks in ST and other PA-related outcomes for the first time using sensor-based data as the criterion. METHODS: In a sample of 858 adults, breaks in ST and other PA-related parameters were assessed through sensor-based accelerometry and subjective data, which included a comprehensive questionnaire with a specific question ('During the day, do you usually sit for a long time in a row or interrupt frequently?') with a three-level closed answer. The Spearman's rank correlation coefficient was used to determine the agreement between the single-item question and sensor-based data. RESULTS: Positive correlations were found for self-reported breaks in ST with sensor-based breaks in ST in both women (ρ=0.37; 95% CI=0.29-0.44) and men (ρ=0.15; 95% CI=0.04-0.26). Self-reported breaks in ST were inversely correlated with ST in women (ρ =-0.33; 95% CI=-0.40 to 0.25). For both sexes, self-reported breaks in ST showed a positive correlation with light-intensity PA (ρ=0.39; 95% CI=0.31-0.46 women; ρ=0.13; 95% CI=0.02-0.24 men), however, positive correlations between self-reported breaks in ST and moderate-to-vigorous PA (ρ=0.13; 95% CI=0.02-0.24) were found only in men. CONCLUSIONS: Our single-item question can be used as an indication for ranking people's breaks in ST during the waking day, although acknowledging that some misclassification will occur, especially in men. There must be an effort to include this question in future national and international surveys to replicate these findings.

Physical activity moderates the effect of sedentary time on an older adult's physical independence.

BACKGROUND/OBJECTIVES: Moderate-to-vigorous physical activity (MVPA) and breaks in sedentary time (BST) have been proposed as viable solutions to improve an older adult's physical independence, whereas sedentary time (ST) has been associated with detrimental effects. We sought to assess the joint effects of ST, BST, and MVPA on the physical independence of older adults and determine whether and to what extent the ST relationship with physical independence is moderated by MVPA and/or BST. DESIGN: Cross-sectional. SETTING: Laboratory of Exercise and Health, Faculty of Human Kinetics. PARTICIPANTS: Older adults (≥65 years old) from the national surveillance system in Portugal (n = 821). MEASUREMENTS: Physical activity and ST were assessed by accelerometry. Physical independence was assessed using a 12-item composite physical function (CPF) questionnaire. Multiple linear regression was used to model the outcomes. RESULTS: Higher ST was related to lower CPF score (ß = -0.01, p < 0.0001), whereas higher MVPA was related to better CPF score (ß = 0.02, p < 0.0001). BST was not related to physical independence after accounting for MVPA and ST (ß = 0.03, p = 0.074). MVPA had a moderating effect on the relationship of ST with CPF score (p < 0.0001), where MVPA ≥36.30 min/day ameliorated the significant inverse relationship between ST and CPF. Engaging in ≥107.78 of MVPA resulted in ST having a significant positive relationship with CPF score. No moderation effect was found for BST (p > 0.05). CONCLUSION: Regardless of the time spent in MVPA and BST, ST was inversely related to CPF. However, MVPA was found to be a moderator of the relationship between ST and physical independence, such that engaging in at least 36 min/day of MVPA may blunt the negative effects of ST. At high levels of MVPA (≥108 min/day), having some ST may actually provide some benefit to an older adult's ability to maintain physical independence.

Sedentary patterns are associated with BDNF in patients with type 2 diabetes mellitus.

PURPOSE: Exercise is beneficial to type-2 diabetes-mellitus (T2DM), and there is evidence showing that one of those benefits include a higher expression of brain-derived neurotrophic factor (BDNF), which has been implicated in improving fat oxidation and cognitive development. The deleterious effect of prolonged sedentary time (ST) on BDNF levels has never been examined in patients with T2DM. Our goal was to analyse the associations for sedentary patterns [i.e. breaks in ST per sedentary hour (BST-ST) and bouts of sedentary time (BSB) of different length] with BDNF in patients with T2DM, independent of moderate-to-vigorous physical activity (MVPA) and cardiorespiratory fitness (CRF). METHODS: Sample included 80 patients (38 women) with T2DM (58.3 ± 7.8 years). ST and MVPA were assessed by accelerometry (ActiGraph, GT3X + model), BDNF by blood collection and plasma quantification using commercial enzyme-linked immunosorbent assay kits, and CRF was determined using a Bruce protocol to exhaustion, on a motorized treadmill. RESULTS: Positive associations for BST-ST (ß = 0.155; p = 0.007) with BDNF, and negative associations for BSB longer than 15 min with BDNF were found (ß = - 0.118; p = 0.049). Neither MVPA nor cardiorespiratory fitness eliminated the associations for BST-ST with BDNF, but MVPA eradicated the associations between BSB > 15 min and BDNF. CONCLUSIONS: Our findings suggest that interrupting ST and especially avoiding longer sedentary periods (> 15 min) may be beneficial for BDNF plasma abundance that may influence metabolic and cognitive functioning of patients with T2DM, especially for the ones presenting lower MVPA levels. TRIAL REGISTRATION: May 5, 2017, ClinicalTrials.govID:NCT03144505.

Recommendations for determining the validity of consumer wearable heart rate devices: expert statement and checklist of the INTERLIVE Network.

Assessing vital signs such as heart rate (HR) by wearable devices in a lifestyle-related environment provides widespread opportunities for public health related research and applications. Commonly, consumer wearable devices assessing HR are based on photoplethysmography (PPG), where HR is determined by absorption and reflection of emitted light by the blood. However, methodological differences and shortcomings in the validation process hamper the comparability of the validity of various wearable devices assessing HR. Towards Intelligent Health and Well-Being: Network of Physical Activity Assessment (INTERLIVE) is a joint European initiative of six universities and one industrial partner. The consortium was founded in 2019 and strives towards developing best-practice recommendations for evaluating the validity of consumer wearables and smartphones. This expert statement presents a best-practice validation protocol for consumer wearables assessing HR by PPG. The recommendations were developed through the following multi-stage process: (1) a systematic literature review based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, (2) an unstructured review of the wider literature pertaining to factors that may introduce bias during the validation of these devices and (3) evidence-informed expert opinions of the INTERLIVE Network. A total of 44 articles were deemed eligible and retrieved through our systematic literature review. Based on these studies, a wider literature review and our evidence-informed expert opinions, we propose a validation framework with standardised recommendations using six domains: considerations for the target population, criterion measure, index measure, testing conditions, data processing and the statistical analysis. As such, this paper presents recommendations to standardise the validity testing and reporting of PPG-based HR wearables used by consumers. Moreover, checklists are provided to guide the validation protocol development and reporting. This will ensure that manufacturers, consumers, healthcare providers and researchers use wearables safely and to its full potential.