Validation of a Zio XT Patch Accelerometer for the Objective Assessment of Physical Activity in the Atherosclerosis Risk in Communities (ARIC) Study.

BACKGROUND: Combination devices to monitor heart rate/rhythms and physical activity are becoming increasingly popular in research and clinical settings. The Zio XT Patch (iRhythm Technologies, San Francisco, CA, USA) is US Food and Drug Administration (FDA)-approved for monitoring heart rhythms, but the validity of its accelerometer for assessing physical activity is unknown. OBJECTIVE: To validate the accelerometer in the Zio XT Patch for measuring physical activity against the widely-used ActiGraph GT3X. METHODS: The Zio XT and ActiGraph wGT3X-BT (Actigraph, Pensacola, FL, USA) were worn simultaneously in two separately-funded ancillary studies to Visit 6 of the Atherosclerosis Risk in Communities (ARIC) Study (2016-2017). Zio XT was worn on the chest and ActiGraph was worn on the hip. Raw accelerometer data were summarized using mean absolute deviation (MAD) for six different epoch lengths (1-min, 5-min, 10-min, 30-min, 1-h, and 2-h). Participants who had ≥3 days of at least 10 h of valid data between 7 a.m-11 p.m were included. Agreement of epoch-level MAD between the two devices was evaluated using correlation and mean squared error (MSE). RESULTS: Among 257 participants (average age: 78.5 ± 4.7 years; 59.1% female), there were strong correlations between MAD values from Zio XT and ActiGraph (average r: 1-min: 0.66, 5-min: 0.90, 10-min: 0.93, 30-min: 0.93, 1-h: 0.89, 2-h: 0.82), with relatively low error values (Average MSE × 106: 1-min: 349.37 g, 5-min: 86.25 g, 10-min: 56.80 g, 30-min: 45.46 g, 1-h: 52.56 g, 2-h: 54.58 g). CONCLUSIONS: These findings suggest that Zio XT accelerometry is valid for measuring duration, frequency, and intensity of physical activity within time epochs of 5-min to 2-h.

Longitudinal association of sedentary time and physical activity with pain and quality of life in fibromyalgia.

OBJECTIVE: To analyze changes over time and the predictive value of baseline and changes of sedentary time (ST) and physical activity (PA) on pain, disease impact, and health-related quality of life (HRQoL) at 2- and 5-year follow-up in women with fibromyalgia. METHODS: This is a longitudinal and exploratory study with three time points. A total of 427 women with fibromyalgia (51.4 ± 7.6 years) were followed after 2 (n = 172) and 5 years (n = 185). ST and PA (light and moderate-to-vigorous [MVPA]) were assessed using triaxial accelerometers. Pain, disease impact, and HRQoL were measured using: pressure pain threshold, the pain subscale of the revised fibromyalgia impact questionnaire (FIQR), the bodily pain subscale of the 36-item short-form health survey (SF-36), a visual analog scale (VAS), the FIQR, and the SF-36 physical and mental components. RESULTS: Over 5 years, pressure pain threshold, ST, light PA, and MVPA variables were worsened, while FIQR and SF-36 variables were improved (Cohen's d < 0.1-0.3). Baseline ST or light PA were not associated with future outcomes, whereas greater MVPA at baseline was associated with better SF-36 bodily pain at 5-year follow-up (ß = 0.13). Reducing ST and increasing light PA were associated with better bodily pain (ß = -0.16 and 0.17, respectively) and SF-36 physical component (ß = -0.20 and 0.17, respectively) at 5-year follow-up. Increasing MVPA was associated with less pain (pressure pain threshold, VAS, and FIQR-pain) and better SF-36 physical component at 2- and 5-year follow-up (ß's from -0.20 to 0.21). CONCLUSIONS: Objectively measured variables slightly worsened over years, while for self-reported outcomes there was a trend for improvement. Reductions in ST and increases in light PA and MVPA were associated with better HRQoL at 5-year follow-up, and increases in MVPA were additionally associated with better pain and HRQoL at 2-year follow-up.

Does the perceived neighborhood environment promote mental health during pregnancy? Confirmation of a pathway through social cohesion in two Spanish samples.

Physical neighborhood attributes such as greenness, walkability and environmental pollution may have an influence on people's behavior and health. It has been claimed that part of such effects may come from the promotion of physical activity and the strengthening of social cohesion. In this study, we recruited samples of pregnant women in two Spanish cities (Donostia-San Sebastián, 440 participants and Barcelona, 360 participants) who filled in a questionnaire and wore an accelerometer for 1 week during the first trimester of pregnancy. The influence of perceived residential greenness, walkability and environmental pollution on mental health (GHQ-12) was tested in two structural equation models that included light physical activity, moderate-to-vigorous physical activity and social cohesion as mediators. Two solutions showing excellent and good fits (Donostia-San Sebastián: X2(3) = 2.56, p = .465, CFI = 1, RMSEA < 0.001; Barcelona: X2(6) = 4.86, p = .566, CFI = 1, RMSEA = 0.048) consistently showed that neighborhood attributes promote mental health through social cohesion in the two cities. Stratified analyses revealed that the social cohesion-mental health effect was only statistically significant for low and medium socioeconomic status groups in the Donostia-San Sebastián sample. Pathways through physical activity were not confirmed.

Reliability of ActiGraph GT3X+ placement location in the estimation of energy expenditure during moderate and high-intensity physical activities in young and older adults.

WHO defines physical activity (PA) as any bodily movement produced by skeletal muscles that requires energy expenditure (EE). The purpose of this study was to compare the EE estimations by ActiGraph GT3X+ with a gold standard measurement, the portable gas analyser in a set of 3 different PAs. This cross-sectional study involved 56 participants, age range (years, [min, max]: young people [20, 33], older adults [65, 83]). Participants completed a single session of three experimental PAs including biking, treadmill walking, and treadmill running. Each participant wore five GT3X+ triaxial accelerometers and a portable gas analyser used as the gold standard measurement. The GT3X+ were placed on the wrists, the waist (centred at the pelvis), and the ankles. ActiGraph GT3X+ and MetaMax3B records were investigated through intraclass correlation coefficient. Magnitude of measurement error was estimated using Effect Size. The GT3X+ wrist and GT3X+ waist underestimated EE regardless of the PA type. The GT3X+ ankles strongly overestimated EE during biking (mean bias = 489 ± 392%) and walking (mean bias = 106 ± 58%), while it underestimated EE during running (mean bias = -47 ± 27%). The ActiGraph GT3X+ does not provide accurate EE estimates across a range of placement locations during moderate and high-intensity PA.

Patterns and correlates of objectively measured physical activity in 3-year-old children.

BACKGROUND: To increase the knowledge about physical activity (PA) patterns and correlates among children under the age of 4, there is a need for study's using objective measurements. The aim of this study was therefore to investigate if objectively measured PA among 3-year-old children differed between day of week and time of day and whether it correlated to child weight status and sex as well as parental weight status and education. METHODS: Totally 61 children (51% girls) aged 3, participating in Early Stockholm Obesity Prevention Project were included. PA was measured with a tri-axial accelerometer (ActiGraph GT3X+) worn on the non-dominant wrist for one week. The main outcome was average PA expressed as counts per minute from the vector magnitude. PA and demographics/family-related factors were collected at baseline and at age 3. To analyze the results simple linear regression, ANOVA and paired t-tests were performed. RESULTS: The mean number of valid days was 6.7 per child. The children were more active on weekdays than weekends (p < 0.01) and the hourly pattern differed over the day with children being most active midmorning and midafternoon (p = 0.0001). Children to parents with low education were more active (p = 0.01) than those with highly educated parents. No differences in PA by child weight status, sex nor parental weight status were found. CONCLUSIONS: PA in 3-year-old children was lower during weekends than weekdays and varied over the day. Boys and girls had similar PA patterns, these patterns were independent of child or parental weight status. Children to parents with low education were more active than their counterparts. The fact that PA differed between weekdays and weekends indicates that PA might be affectable in 3-year-old children.

Comparing physical activity estimates in children from hip-worn Actigraph GT3X+ accelerometers using raw and counts based processing methods.

This study examined differences in physical activity (PA) estimates provided from raw and counts processing methods. One hundred and sixty-five children (87 girls) wore a hip-mounted ActiGraph GT3X+ accelerometer for 7 days. Data were available for 129 participants. Time in moderate PA (MPA), vigorous PA (VPA) and moderate-vigorous PA (MVPA) were calculated using R-package GGIR and ActiLife. Participants meeting the wear time criteria for both processing methods were included in the analysis. Time spent in MPA (-21.4 min.d-1, 95%CI -21 to -20) and VPA (-36 min.d-1, 95%CI -40 to -33) from count data were higher (P < 0.001) than raw data. Time spent in MVPA between the two processing methods revealed significant differences (All P < 0.001). Bland-Altman plots suggest that the mean bias for time spent in MPA, VPA and MVPA were large when comparing raw and count methods. Equivalence tests showed that estimates from raw and count processing methods across all activity intensities lacked equivalence. Lack of equivalence and poor agreement between raw and count processing methods suggest the two approaches to estimate PA are not comparable. Further work to facilitate the comparison of findings between studies that process and report raw and count physical activity data may be necessary.

On Placement, Location and Orientation of Wrist-Worn Tri-Axial Accelerometers during Free-Living Measurements.

Wearable accelerometers have recently become a standalone tool for the objective assessment of physical activity (PA). In free-living studies, accelerometers are placed by protocol on a pre-defined body location (e.g., non-dominant wrist). However, the protocol is not always followed, e.g., the sensor can be moved between wrists or reattached in a different orientation. Such protocol violations often result in PA miscalculation. We propose an approach, PLOE ("Placement, Location and Orientation Evaluation method"), to determine the sensor position using statistical features from the raw accelerometer measurements. We compare the estimated position with the study protocol and identify discrepancies. We apply PLOE to the measurements collected from 45 older adults who wore ActiGraph GT3X+ accelerometers on the left and right wrist for seven days. We found that 15.6% of participants who wore accelerometers violated the protocol for one or more days. The sensors were worn on the wrong hand during 6.9% of the days of simultaneous wearing of devices. During the periods of discrepancies, the daily PA was miscalculated by more than 20%. Our findings show that correct placement of the device has a significant effect on the PA estimates. These results demonstrate a need for the evaluation of sensor position.

Wear compliance, sedentary behaviour and activity in free-living children from hip-and wrist-mounted ActiGraph GT3X+ accelerometers.

The GT3X+ worn at the wrist promotes greater compliance than at the hip. Minutes in SB and PA calculated from raw accelerations at the hip and wrist provide contrasting estimates and cannot be directly compared. Wear-time for the wrist (15.6 to 17.4 h.d-1) was greater than the hip (15.2 to 16.8 h.d-1) across several wear-time criteria (all P < 0.05). Moderate-strong associations were found between time spent in SB (r = 0.39), LPA (r = 0.33), MPA (r = 0.99), VPA (r = 0.82) and MVPA (r = 0.81) between the two device placements (All P < 0.001). The wrist device detected more minutes in LPA, MPA, VPA and MVPA whereas the hip detected more SB (all P = 0.001). Estimates of time in SB and all activity outcomes from the wrist and hip lacked equivalence. One hundred and eighty-eight 9-12-year-old children wore a wrist- and hip-mounted accelerometer for 7 days. Data were available for 160 (hip) and 161 (wrist) participants. Time spent in SB and PA was calculated using GGIR. This study examined the compliance of children wearing wrist- and hip-mounted ActiGraph GT3X+ accelerometers and compared estimates of sedentary behaviour (SB) and physical activity (PA) between devices.

Association of sedentary time and physical activity with pain, fatigue, and impact of fibromyalgia: the al-Ándalus study.

We examined the association of objectively measured sedentary time (ST) and physical activity (PA) levels with pain, fatigue, and the impact of the disease in women with fibromyalgia. Four hundred and nineteen (mean age ± SD = 51.7 ± 7.6 years old) women with fibromyalgia participated. ST and PA levels (light, moderate, and moderate-to-vigorous [MVPA]) were measured with triaxial accelerometry. We assessed experimental pain with algometry and clinical pain, fatigue, and impact of fibromyalgia with a number of questionnaires. The association of ST and light PA with most of the pain- and fatigue-related outcomes and impact of fibromyalgia (all, P ≤ 0.019) was independent of moderate and vigorous PA. Furthermore, the association of vigorous PA with general and physical fatigue was independent of ST and light and moderate PA (all, P < 0.001). In conclusion, lower levels of ST or higher levels of light PA are associated with lower pain, fatigue, and the overall impact of the disease independent of moderate and vigorous PA in women with fibromyalgia. Interestingly, higher vigorous PA is independently associated with lower general and physical fatigue. These results are significant for future ST and PA intervention studies in this population.

Comparison of children's free-living physical activity derived from wrist and hip raw accelerations during the segmented week.

This study assessed children's physical activity (PA) levels derived from wrist-worn GENEActiv and hip-worn ActiGraph GT3X+ accelerometers and examined the comparability of PA levels between the two devices throughout the segmented week. One hundred and twenty-nine 9-10-year-old children (79 girls) wore a GENEActiv (GAwrist) and ActiGraph GT3X+ (AGhip) accelerometer on the left wrist and right hip, respectively, for 7 days. Mean minutes of light PA (LPA) and moderate-to-vigorous PA (MVPA) per weekday (whole-day, before-school, school and after-school) and weekend day (whole-day, morning and afternoon-evening) segments were calculated, and expressed as percentage of segment time. Repeated measures analysis of variance examined differences in LPA and MVPA between GAwrist and AGhip for each time segment. Bland-Altman plots assessed between-device agreement for LPA and MVPA for whole weekday and whole weekend day segments. Correlations between GAwrist and AGhip were weak for LPA (r = 0.18-0.28), but strong for MVPA (r = 0.80-0.86). LPA and MVPA levels during all weekday and weekend day segments were significantly higher for GAwrist than AGhip (p < 0.001). The largest inter-device percent difference of 26% was observed in LPA during the school day segment. Our data suggest that correction factors are needed to improve raw PA level comparability between GAwrist and AGhip.

Independent and joint associations of physical activity and fitness with fibromyalgia symptoms and severity: The al-Ándalus project.

We examined independent and joint associations of objectively measured physical activity (PA) and physical fitness (PF) with pain, fatigue and the overall impact of fibromyalgia in 386 fibromyalgia women aged 51.2 ± 7.6 years. Levels of PA (light, moderate and vigorous) and PF were measured with triaxial accelerometry and the Senior Fitness Test, respectively. We used the Short-Form health survey-36 pain sub-scale and the Multidimensional Fatigue Inventory to assess pain and multiple dimensions of fatigue, respectively. The impact of fibromyalgia was studied with the Revised Fibromyalgia Impact Questionnaire (FIQR). Both, total PA and global PF were independently associated with pain pressure threshold, SF-36 pain, reduced activity, reduced motivation and FIQR total score (all, P ≤ 0.027). The associations between total PA and symptoms were weaker than those observed between global PF and symptoms. Overall, unfit patients with low PA showed a worse profile that fit patients with high PA (all, P ≤ 0.001). In summary, PA and PF are independently associated with pain, fatigue and the overall impact of fibromyalgia in women. Although PF presented greater associations with symptoms, the results suggest that both being physically active and keep adequate fitness levels might be convenient for fibromyalgia women.

Categorical answer modes provide superior validity to open answers when asking for level of physical activity: A cross-sectional study.

AIMS: Physical activity (PA) used as prevention and treatment of disease has created a need for effective tools for measuring patients' PA level. Our aim was therefore to assess the validity of two PA questions and their three associated answer modes. METHODS: Data on PA according to the PA questions and Actigraph GT3X+ accelerometers, aerobic fitness (VO(2)max), cardiovascular biomarkers, and self-rated general health were collected in 365 Swedish adults (21-66 years). The PA questions ask about weekly PA via categories (Categorical), an open-ended answer (Open), or specified day by day (Table). RESULTS: The Categorical mode, compared with the Open mode, correlated (Spearman's rho) significantly more strongly (p<0.05) with accelerometer PA (0.31 vs. 0.18) and VO(2)max (0.27 vs. 0.06), and the level of BMI (-0.20 vs. -0.02), waist circumference (-0.22 vs. -0.03), diastolic blood pressure (-0.16 vs. 0.08), glucose (-0.18 vs. 0.04), triglycerides (-0.31 vs. -0.07), and general health (0.35 vs. 0.19). The validity of the Categorical and Table modes were similar regarding VO(2)max and accelerometry, but the Categorical mode exhibited more significant and stronger correlations with cardiovascular biomarkers. The capacity of the PA questions to identify insufficiently physically active individuals ranged from 0.57 to 0.76 for sensitivity and from 0.47 to 0.79 for specificity. CONCLUSIONS: The Categorical mode exhibits the strongest validity and Open mode the weakest. The PA questions may be used on a population level, or as a tool for determining patents' appropriateness for treatment.

Sedentary time is associated with depressive symptoms and state anxiety in women with fibromyalgia. Could physical activity and fitness modify this association? The al-Ándalus project.

PURPOSE: To analyze the associations of total and prolonged sedentary time (ST) with depressive symptoms and state anxiety in women with fibromyalgia and whether these associations are modified by moderate-to-vigorous physical activity (MVPA) and physical fitness. METHODS: This cross-sectional exploratory study included 386 women with fibromyalgia aged 51.2 ± 7.6 years. Total ST, time in prolonged bouts of ST (≥30- and ≥60-min) and MVPA were measured with triaxial accelerometry. Depressive symptoms were assessed with the "Beck Depression Inventory-second edition," state anxiety with the "State-Trait Anxiety Inventory," and physical fitness with the "Senior Fitness Test Battery." RESULTS: Total and prolonged ST were directly associated with depressive symptoms (total: ß = 0.19, ≥30-min bout: ß = 0.15, and ≥60-min bout: ß = 0.12) and odds of severe depressive symptoms (all, p < 0.001). These associations generally remained significant after adjustments for MVPA and physical fitness (all, p < 0.05). Total and prolonged ST were directly associated with state anxiety (total: ß = 0.11, ≥30-min bout: ß = 0.12, and ≥60-min bout: ß = 0.07; all, p < 0.001). These associations were generally independent of MVPA (p < 0.05) but vanished when considering physical fitness (p > 0.05). CONCLUSIONS: Higher levels of total and prolonged ST are associated with greater depressive symptoms and state anxiety in women with fibromyalgia. MVPA did not modify these associations, although physical fitness could play a protective role specially for state anxiety.IMPLICATIONS FOR REHABILITATIONReducing sedentary time and avoiding its accumulation in prolonged periods could potentially reduce depressive symptoms and state anxiety in fibromyalgia.Higher sedentary time is associated with more severe depressive symptoms even in patients who engage in moderate-to-vigorous physical activity.Higher levels of physical fitness could attenuate the negative associations of sedentary time with depressive symptoms and, specially, state anxiety."Sit less, move more and exercise to increase your fitness" could be a positive message for people with fibromyalgia in clinical settings.

Agreement between Accelerometer-Assessed and Self-Reported Physical Activity and Sedentary Behavior in Female Breast Cancer Survivors.

An accurate quantitative assessment of physical activity and sedentary lifestyles enables a better understanding of their relationship with the health records of cancer survivors. The objective of this study was to compare the subjective and objective methods of physical activity measurement in female breast cancer survivors. Materials and methods: In total, 135 female breast cancer survivors at the Holycross Cancer Center, Kielce, Poland, were included in this study. A shortened version of the International Physical Activity Questionnaire (IPAQ) was used to subjectively assess the participants' physical activity (PA), and an ActiGraph GT3X-BT accelerometer was used for an objective assessment. In total, 75% of the studied women did not report any vigorous PA, irrespective of the measurement method. The average values of moderate PA and moderate-to-vigorous PA (MVPA) measured with IPAQ compared with the accelerometer were sevenfold and tenfold higher, respectively. Conversely, the sedentary behavior values measured with the accelerometer were almost three times higher than those measured with IPAQ. The PA and sedentary behavior measurements were significantly different. Irrespective of PA intensity, the accelerometer-based measurements produced significantly lower results than IPAQ, while higher results were observed for sedentary behavior. The measurement differences between these two methods increased as the average differences grew. Regardless of the measurement method, a negative association was observed between moderate PA with general adiposity and adipose tissue distribution, whereas sedentary behavior demonstrated an opposite trend. This indicates the detrimental role of obesity in limiting PA.

Relationship Between Parent and Child Physical Activity Using Novel Acceleration Metrics.

Background: Raw acceleration data lend themselves to innovative metrics in which comparisons can be made across populations. This study examined whether the intensity gradient (IG) or average acceleration (AvAcc) was associated with body mass index (BMI) in children and adults and explored parent-child associations between time spent in physical activity intensities and BMI. Methods: Parent-child dyads (n = 90) wore a wrist-mounted ActiGraph GT3X+ monitor for ≥ 3 valid days (i.e., ≥ 16 hrs each day). Participants' BMI was calculated. Results: Girls' BMI-z scores were positively associated with parent BMI and inactive time. Parent BMI was negatively associated with boys' inactive time. Parental inactive time predicted girls' BMI-z scores. The metrics were not associated with parent BMI, and no independent effects were observed between the metrics. Associations between boys' IG and BMI z-score were observed. No independent effects were observed between the metrics and no significant associations were observed between boys' BMI z-score and AvAcc. Girls' AvAcc and IG were not associated with BMI z-score and no independent effects were observed between the metrics. Conclusion: Findings support previous research which suggests that parent's activity does not influence their child's activity.

Comparative Analysis of Physical Activity Detected via an External Accelerometer and Cardiac Implantable Electronic Devices.

Background: Physical activity (PA) has become an important health issue for decades. Cardiovascular implantable electronic devices (CIEDs) have built-in PA-recording functions. We aimed to compare PA measurements using an external accelerometer (ActiGraph GT3X+) and internal accelerometers (Abbott, Biotronik, and Medtronic CIEDs). Methods: This was a prospective, single-center observational study. The device-measured 7-day average PA was collected, and GT3X+ -measured 7-day average PA was used as the gold-standard, including all daily observations of activity. Pearson's correlation coefficients were used to compare the correlations between GT3X+ -measured and CIED-measured PA. Bland-Altman plots were used to analyze measurement agreement, and intraclass correlation coefficients were used to analyze reliability. Results: In total, 720 patients treated with CIEDs were surveyed between November 2020 and April 2021, 60 of them were analyzed after patient screening by our protocol. Each manufacturer included 20 patients for the final analysis. The CIED-measured PAs of Abbott, Biotronik, and Medtronic were 3.0 ± 1.5, 2.6 ± 1.8, and 3.8 ± 2.5 h per day, respectively; the GT3X+ -measured PAs were 6.9 ± 2.8, 6.0 ± 2.4, and 6.4 ± 2.5 h per day, respectively. Moderate and significant correlations were found in patients using Abbott, Biotronik, and Medtronic CIEDs (r = 0.534, p = 0.015; r = 0.465, p = 0.039; r = 0.677, p = 0.001, respectively). Bland-Altman plots and intraclass correlation coefficients both showed a significant correlation and reliability between the average PA measured by GT3X+ and CIEDs (hours per day). Conclusion: Although the PA recording function of CIEDs includes a single-axis accelerometer, it has a moderate correlation compared with the triaxial accelerometer of the GT3X+. However, CIEDs seem to underestimate PA for 3-4 h compared to the GT3X+.

Accuracy of steps measured by smartphones-based WeRun compared with ActiGraph-GT3X accelerometer in free-living conditions.

Objectives: The purpose of this study was to evaluate the accuracy and reliability of steps tracked by smartphone-based WeChat app compared with Actigraph-GT3X accelerometer in free-living conditions. Design: A cross-sectional study and repeated measures. Methods: A total of 103 employees in the Pudong New Area of Shanghai, China, participated in this study. The participants wore an ActiGraph-GT3X accelerometer during the period of August to September 2019 (Time 1), December 2019 (Time 2) and September 2020 (Time 3). Each time, they wore the ActiGraph-GT3X accelerometer continuously for 7 days to assess their 7-day step counts. The smartphone-based WeRun step counts were collected in the corresponding period when subjects wore accelerometers. The subjects were invited to complete basic demographic characteristics questionnaires and to perform physical examination to obtain health-related results such as height, body weight, body fat percentage, waist circumference, hip circumference, and blood pressure. Results: Based on 103 participants' 21 days of data, we found that the Spearman correlation coefficient between them was 0.733 (P < 0.01). The average number of WeRun steps measured by smartphones was 8,975 (4,059) per day, which was higher than those measured by accelerometers (8,462 ± 3,486 per day, P < 0.01). Demographic characteristics and different conditions can affect the consistency of measurements. The consistency was higher in those who were male, older, master's degree and above educated, and traveled by walking. Steps measured by smartphone and accelerometer in working days and August showed stronger correlation than other working conditions and time. Mean absolute percent error (MAPE) for step counts ranged from 0.5 to 15.9%. The test-retest reliability coefficients of WeRun steps ranged from 0.392 to 0.646. A multiple regression analysis adjusted for age, gender, and MVPA/step counts measured during Time 1 showed that body composition (body weight, BMI, body fat percentage, waist circumference, and hip circumference) was correlated with moderate-to-vigorous intensity physical activity, but it was not correlated with WeRun step counts. Conclusions: The smartphone-based WeChat app can be used to assess physical activity step counts and is a reliable tool for measuring steps in free-living conditions. However, WeRun step counts' utilization is potentially limited in predicting body composition.

Associations of physical activity, sedentary time, and physical fitness with mental health during pregnancy: The GESTAFIT project.

PURPOSE: This study was aimed to analyze the associations of objectively measured physical activity (PA), sedentary time, and physical fitness with mental health in the early second trimester (16 ± 2 gestational weeks) of pregnancy. METHODS: From 229 women initially contacted, 124 pregnant women participated in the present cross-sectional study. Data were collected between November 2015 and March 2017. The participants wore Actigraph GT3X+ Triaxial accelerometers for 9 consecutive days to objectively measure their PA levels and sedentary time. A performance-based test battery was used to measure physical fitness. Self-report questionnaires assessed psychological ill-being (i.e., negative affect, anxiety, and depression), and psychological well-being (i.e., emotional intelligence, resilience, and positive affect). Linear regression analyses were adjusted for age, educational level, accelerometer wear time, miscarriages, and low back pain. RESULTS: Moderate-to-vigorous PA was negatively associated with depression (ß = -0.222, adjusted R2 = 0.050, p = 0.041). Higher levels of sedentary time were negatively associated with positive affect (ß = -0.260, adjusted R2 = 0.085, p = 0.017). Greater upper-body flexibility was positively associated with better emotional regulation (ß = 0.195, adjusted R2= 0.030, p = 0.047). The remaining associations were not significant (all p > 0.05). CONCLUSION: An active lifestyle characterized by higher levels of moderate-to-vigorous PA and lower levels of sedentary time during pregnancy might modestly improve the mental health of pregnant women. Although previous research has focused on the benefits of cardiorespiratory exercise, the present study shows that only upper-body flexibility is related to emotional regulation in early pregnant women. If the present findings are corroborated in further experimental research, physical exercise programs should focus on enhancing flexibility to promote improvements in emotional regulation during early second-trimester of pregnancy.

Patterns of Sedentary Time and Quality of Life in Women With Fibromyalgia: Cross-Sectional Study From the al-Ándalus Project.

BACKGROUND: Sedentary time (ST) has been associated with detrimental health outcomes in fibromyalgia. Previous evidence in the general population has shown that not only is the total amount of ST harmful but the pattern of accumulation of sedentary behaviors is also relevant to health, with prolonged unbroken periods (ie, bouts) being particularly harmful. OBJECTIVE: To examine the association of the patterns of ST with health-related quality of life (HRQoL) in women with fibromyalgia and to test whether these associations are independent of moderate-to-vigorous physical activity (MVPA). METHODS: A total of 407 women (mean 51.4 years of age [SD 7.6]) with fibromyalgia participated. ST and MVPA were measured with triaxial accelerometry. The percentage of ST accumulated in bouts and the frequency of sedentary bouts of different lengths (≥10 min, ≥20 min, ≥30 min, and ≥60 min) were obtained. Four groups combining total ST and sedentary bout duration (≥30 min) were created. We assessed HRQoL using the 36-item Short-Form Health Survey (SF-36). RESULTS: A greater percentage of ST spent in all bout lengths was associated with worsened physical function, bodily pain, vitality, social function, and physical component summary (PCS) (all P<.05). In addition, a higher percentage of ST in bouts of 60 minutes or more was related to worsened physical role (P=.04). A higher frequency of bouts was negatively associated with physical function, social function, the PCS (≥30 min and ≥60 min), physical role (≥60 min), bodily pain (≥60 min), and vitality (≥20 min, ≥30 min, and ≥60 min) (all P<.05). Overall, for different domains of HRQoL, these associations were independent of MVPA for higher bout lengths. Patients with high total ST and high sedentary bout duration had significantly worsened physical function (mean difference 8.73 units, 95% CI 2.31-15.15; independent of MVPA), social function (mean difference 10.51 units, 95% CI 2.59-18.44; not independent of MVPA), and PCS (mean difference 2.71 units, 95% CI 0.36-5.06; not independent of MVPA) than those with low ST and low sedentary bout duration. CONCLUSIONS: Greater ST in prolonged periods of any length and a higher frequency of ST bouts, especially in longer bout durations, are associated with worsened HRQoL in women with fibromyalgia. These associations were generally independent of MVPA.

Towards a Functional Approach to the Assessment of Daily Life Physical Activity in Children: Are the PAQ-C and Fitbit Flex-2 Technically Adequate?

Considering the need for functional physical activity (PA) measures in PA settings, this study sought to determine the technical adequacy of the Physical Activity Questionnaire for Older Children (PAQ-C) and the Fitbit Flex-2, two instruments with promising features for wide use, using the Actigraph GT3X+ accelerometer as the criterion reference. A total of 218 Greek children (94 boys, 124 girls; mean age = 10.99 ± 1.52 years) volunteered to join in. Participants wore the PA trackers for seven days and completed the PAQ-C. Moreover, a sub-group (n = 60) recompleted the PAQ-C after a week. Results revealed acceptable internal consistency and excellent test-retest reliability for the PAQ-C. Regarding concurrent validity, weak to moderate correlations with PA parameters recorded by the GT3X+ were revealed for the total PAQ-C and were excellent for the Flex-2, while a Bland-Altman plot indicated good agreement. Finally, in alignment with relevant literature, significant gender, but no age, differences were found in participants' PA records in all the tools applied. The above results support the use of the PAQ-C and the Fitbit Flex-2 in children. Considering that they shed light into different parameters of children's habitual PA, their combined utilisation, providing comprehensive information, is strongly recommended.