Link Accelerometers Research Articles

Physical activity among pregnant inpatients and outpatients and associations with anxiety

ObjectivePhysical activity is linked to lower anxiety, but little is known about the association during pregnancy. This is especially important for antepartum inpatients, who are known to have increased anxiety yet may not be able to achieve target levels of physical activity during hospitalization. We compared physical activity metrics between pregnant inpatients and outpatients and explored correlations with anxiety. Materials and MethodsThis was a prospective cohort between 2021 and 2022 of pregnant people aged 18–55 years carrying singleton gestations ≥ 16 weeks. Three exposure groups were matched for gestational age: 1) outpatients from general obstetric clinics; 2) outpatients from high-risk Maternal-Fetal Medicine obstetric clinics; and 3) antepartum inpatients. Participants wore Actigraph GT9X Link accelerometer watches for up to 7 days to measure physical activity. The primary outcome was mean daily step count. Secondary outcomes were metabolic equivalent tasks (METs), hourly kilocalories (kcals), moderate to vigorous physical activity (MVPA) bursts, and anxiety (State-Trait Anxiety Inventory [STAI]). Step counts were compared using multivariable generalized estimating equations adjusting for maternal age, body-mass index, and insurance type as a socioeconomic construct, accounting for within-group clustering by gestational age. Spearman correlations were used to correlate anxiety scores with step counts. Results58 participants were analyzed. Compared to outpatients, inpatients had significantly lower mean daily steps (primary outcome, adjusted beta −2185, 95 % confidence interval [CI] −3146, −1224, p < 0.01), METs (adjusted beta −0.18, 95 % CI −0.23, −0.13, p < 0.01), MVPAs (adjusted beta −38.2, 95 % CI −52.3, −24.1, p < 0.01), and kcals (adjusted beta –222.9, 95 % CI −438.0, −7.8, p = 0.04). Over the course of the week, steps progressively decreased for inpatients (p-interaction 0.01) but not for either of the outpatient groups. Among the entire cohort, lower step counts correlated with higher anxiety scores (r = 0.30, p = 0.02). ConclusionWe present antenatal population norms and variance for step counts, metabolic equivalent tasks, moderate to vigorous physical activity bursts, and kcals, as well as correlations with anxiety. Antepartum inpatients had significantly lower physical activity than outpatients, and lower step counts correlated with higher anxiety levels. These results highlight the need for physical activity interventions, particularly for hospitalized pregnant people.

Abstract 18530: Associations Among Self-Reported and Physiologic Sleep Measurements and Fatigue in Adults Following Major Cardiac Events

Background: Insufficient sleep contributes to fatigue and cardiometabolic disorders. Current sleep measures vary in accuracy, with weak correlations between self-report and physiologic measures. Developing reliably associated self-report and physiologic sleep measures can optimize data collection methods. Purpose: Investigate correlations between self-reported and physiologic sleep measures in cardiac rehabilitation patients and determine associations with fatigue. Methods: Participants (N = 25, 58% male, 89% non-Hispanic white, mean age = 61 years) recruited from cardiac rehabilitation centers participated in a three-arm RCT. Inclusion criteria were experiencing a myocardial infarction or revascularization procedure, enrollment in cardiac rehabilitation, and experiencing depression or anxiety. Participants without complete sleep measures were excluded. Data was collected at baseline, 3-, and 6-months. Sleep was measured over 8 days with an investigator-developed self-report diary and an ActiGraph GT9X Link accelerometer. ActiGraphs collected data with a 30Hz sampling rate and were scored using the autodetected sleep periods to determine total sleep time. Mean daily minutes of sleep were calculated from self-report and ActiGraph data. Participants also completed a demographics survey and Fatigue Severity Scale. Statistical methods included Pearson correlation coefficients with 95% confidence intervals (CI) estimated with Fisher's r-to-z transformation. Results: Results showed self-reported and ActiGraph measured sleep were highly correlated (r = 0.889, [95% CI 0.812, 0.935], p &lt; 0.001). Fatigue was not correlated with self-reported (r = 0.074, [95% CI -0.206, 0.342] p = 0.607) or ActiGraph measured sleep (r = 0.150, [95% CI -0.131, 0.408] p = 0.295). Even though the finding was non-significant, the correlation between fatigue and ActiGraph measured sleep was larger than self-reported sleep. Conclusion: Accurate sleep measures are essential to inform future research and interventions. Unlike past work, this investigator-developed, self-report measure was strongly correlated with the physiologic measure. Researchers should consider reliability when selecting sleep measures.

Acute effects of exergaming on young adults' energy expenditure, enjoyment, and self-efficacy.

This study investigated the effects of a dance-based exergaming on Chinese college students' energy expenditure, self-efficacy, and enjoyment in comparison with the traditional aerobic dance exercise. Forty young adults (33 females; Mage = 21.55 years, SD = 2.06) completed two separate 20 min exercise sessions with 10 min intervals on the same day: (1) Xbox 360 Kinect Just Dance exergaming session; and (2) a traditional instructor-led aerobic dance exercise session. Participants' energy expenditure (Kcal/session) was measured by the ActiGraph GT9X Link accelerometers, and their perceived self-efficacy and enjoyment were assessed via validated surveys following each session. Dependent t-test indicated significant differences in participants' enjoyment (t = -1.83, p = 0.04). Specifically, participants in the dance-based exergaming session reported a higher level of enjoyment (M = 3.96, SD = 0.65) as compared to the aerobic dance session (M = 3.61, SD = 0.54). However, there was no significant difference in energy expenditure and self-efficacy between the two sessions. Findings suggest that college students had comparable energy expenditure as the traditional aerobic dance session while experiencing more fun and enjoyment. This suggests that exergaming can be a fun exercise alternative for promoting physical activity among young adults.

Sex moderates the associations between physical activity intensity and attentional control in older adolescents.

The relationship between physical activity (PA) intensity and executive functions in older adolescents remains poorly understood. This study aimed to examine the associations between PA intensity, volume, attentional control, and working memory and the moderating effects of sex in older adolescents. We analyzed baseline data from 418 participants (211 females, Mage =16.5 ± 0.40 years) from the Burn 2 Learn trial. Adolescents wore GT9X Link accelerometers on a non-dominant wrist for 7 days, 24-h·d-1 . PA intensity was expressed as intensity gradient (IG) and moderate-to-vigorous PA (MVPA, Hildebrand cut-points); PA volume was expressed as average acceleration (AvACC). Attentional control was measured with a standard deviation (SDRT) and a coefficient of variation (CVRT) of the reaction time on the incongruent trials of a flanker task. Working memory was expressed as a d prime (a signal discrimination index) on the 2-back task. The moderating effects of sex on the PA-executive functions associations, adjusting for age, BMI z-score, and cardiorespiratory fitness, were tested using multilevel random intercept models. After controlling for AvACC, sex moderated the relationships between IG and incongruent SDRT (B=0.53, 95% CI: 0.12, 0.94) and CVRT (B=0.63, 95% CI: 0.22, 1.05; ps ≤ 0.002). Only girls with higher IG showed smaller incongruent SDRT and CVRT (Bs ≤ -0.26, ps ≤ 0.01). IG was not related to working memory. AvACC and MVPA were not associated with attentional control or working memory. Our findings reveal a novel association between higher-intensity PA and superior attentional control among adolescent girls.

Increasing Physical Activity and Fundamental Movement Skills of Primary School Students during the Covid-19 through Exergame

Study purpose. The low physical activity and fundamental movement skills of students in the COVID-19 era are gaps in this study. This study aims to exam the effects of exergame on the physical activity and fundamental movement skills of students during the COVID-19 era.&#x0D; Materials and methods. Quantitative research with experimental methods was used in this study. The subjects of this study came from students at primary schools 1 and 2 in Karawang (n = 120). Subjects from primary school 1 Karawang entered the experimental group (n = 60), namely getting treatment in the form of exergame, and subjects from primary school 2 Karawang were included in the control group (n = 60) who did not receive any treatment and only carried out physical education learning activities. The intervention program was carried out for seven weeks. To measure the physical activity of the students, the ActiGraph GT9X Link accelerometer was used, and the fundamental movement skills of the children were assessed using the TGMD-3.&#x0D; Results. The results showed that the implementation of exergame was proven to significantly improve physical activity (p &lt; 0.05) and the same results show that exergame has a significant effect on fundamental movement skills (p &lt; 0.05). However, there was no increase in physical activity and fundamental movement skills in the control group (p &gt; 0.05).&#x0D; Conclusions. This research is evidence that exergame is an effective tool to improve physical activity and fundamental movement skills students during the COVID-19 era.

Limb accelerations during sleep are related to measures of strength, sensation, and spasticity among individuals with spinal cord injury

BackgroundTo evaluate the relationship between measures of neuromuscular impairment and limb accelerations (LA) collected during sleep among individuals with chronic spinal cord injury (SCI) to provide evidence of construct and concurrent validity for LA as a clinically meaningful measure.MethodsThe strength (lower extremity motor score), sensation (summed lower limb light touch scores), and spasticity (categorized lower limb Modified Ashworth Scale) were measured from 40 adults with chronic (≥ 1 year) SCI. Demographics, pain, sleep quality, and other covariate or confounding factors were measured using self-report questionnaires. Each participant then wore ActiGraph GT9X Link accelerometers on their ankles and wrist continuously for 1–5 days to measure LA from movements during sleep. Regression models with built-in feature selection were used to determine the most relevant LA features and the association to each measure of impairment.ResultsLA features were related to measures of impairment with models explaining 69% and 73% of the variance (R²) in strength and sensation, respectively, and correctly classifying 81.6% (F1-score = 0.814) of the participants into spasticity categories. The most commonly selected LA features included measures of power and frequency (frequency domain), movement direction (correlation between axes), consistency between movements (relation to recent movements), and wavelet energy (signal characteristics). Rolling speed (change in angle of inclination) and movement smoothness (median crossings) were uniquely associated with strength. When LA features were included, an increase of 72% and 222% of the variance was explained for strength and sensation scores, respectively, and there was a 34% increase in spasticity classification accuracy compared to models containing only covariate features such as demographics, sleep quality, and pain.ConclusionLA features have shown evidence of having construct and concurrent validity, thus demonstrating that LA are a clinically-relevant measure related to lower limb strength, sensation, and spasticity after SCI. LA may be useful as a more detailed measure of impairment for applications such as clinical prediction models for ambulation.

Gender, activity participation, education levels, and depressive symptoms predict activity participation levels at post-cardiac rehabilitation

BACKGROUND: Little is known about predictors of activity participation that are objectively measured in cardiac rehabilitation (CR) graduates. This prospective observational study aimed to determine the predictors of objectively measured activity participation among adults with chronic cardiac conditions who have completed Phase II CR. METHODS: Twenty-five adults with chronic cardiac conditions graduating from traditional CR program participated in the study. The outcome variable was an activity participation level measured by light-to-vigorous intensity physical activity (LVPA) minutes using ActiGraph GT9X Link accelerometer after CR discharge. Covariates were collected at the discharge from CR, and outcome variables were collected at 1 month, 3 months, and 9 months post CR discharge. RESULTS: Gender, standardized LVPA at CR discharge, body mass index, and motivation for physical activity and leisure were significantly associated with the activity participation levels at 1 month, 3 months, and/or 9 months post CR discharge. Gender, standardized LVPA at CR discharge, highest education completed, and depressive symptoms significantly predicted the activity participation levels at 1 month (R2 = 0.69, p &lt; 0.001), 3 months (R2 = 0.65, p &lt; 0.001), and/or 9 months (R2 = 0.80, p &lt; 0.001) post CR discharge. Female CR participants who were more active, had more than high school education, and showed more depressive symptoms at CR discharge were more likely to be active post CR. CONCLUSIONS: CR participants may benefit from individualized approach to plan their days post CR and application-focused and education-level sensitive sessions to understand the importance of activity participation maintenance post CR.

Do fundamental movement skills, physical activity and enjoyment among inactive student during the COVID-19 Era improve after exergame?

The low fundamental movement skills, physical activity and enjoyment students in the COVID-19 era are gaps in this study. This study aims to examine the effects of exergame on fundamental movement skills, physical activity and enjoyment in among inactive students during the COVID-19 era. Quantitative research with experimental methods was used in this study. There were 26 children allocated to the exergame group (n=13; age: 7.20±1.30 years; height: 1.38±2.38 cm; weight: 31.60±4.50 kg and a control group n=13; age: 7.40±1.14 years; height: 1.36±3.08 cm; weight: 28.40±3.43 kg). The intervention program was conducted for nine weeks. Fundamental movement skills children were assessed using the TGMD-3 and physical activity was measured using the ActiGraph GT9X Link accelerometer, while enjoyment was assessed using the physical education curriculum enjoyment scale. The results showed that the implementation of exergame was proven to improve fundamental movement skills, physical activity and enjoyment significantly. However, there was no increase in fundamental movement skills, physical activity and enjoyment in the control group. This research is evidence that exergame is an effective tool to improve fundamental movement skills, physical activity and enjoyment in among inactive students during the COVID-19 era.

Investigating Relationships between Preschool Children's Perceived Competence, Motor Skills, and Physical Activity: A Cross-Lagged Panel Model.

Background: Motor skill competence (MSC) and perceived competence (PC) are primary correlates that are linked with physical activity (PA) participation, yet there is limited evidence of the mutual longitudinal or temporal associations between these variables in preschoolers. Therefore, this study’s purpose was to examine the bidirectional relationships between MSC and PA, MSC and PC, and PC and PA in preschoolers over time. Methods: The final sample were 61 preschoolers (Mage = 4.45 years, ranging from 4 to 5) from two underserved schools. MSC was assessed using the Test of Gross Motor Development, Second Edition (TGMD-2). PC was assessed using the Pictorial Scale of Perceived Competence and Social Acceptance for Young Children. PA was assessed using ActiGraph GT9X Link accelerometers during three consecutive school days. All assessments of MSC, PC, and PA were measured in identical conditions at schools at the baseline (T1) and the end of the eighth week (T2). We employed a cross-lagged model approach to understand the bidirectional relationships between MSC, PC, and PA. Results: The results showed that T1 MSC significantly predicted T2 MSC (p < 0.01) and T1 MSC significantly predicted T2 PA only in girls (p = 0.03). Additionally, a cross-lagged effect of T1 MSC and T2 PC was only observed in boys (p = 0.03). Lastly, a significant association for T1 moderate-to-vigorous physical activity (MVPA) and T2 PC was only observed in girls (p = 0.04). Conclusions: Bidirectional relationships between the variables were not observed in preschoolers. However, significant gender differences were observed in each cross-lagged model.

Time-efficient physical activity intervention for older adolescents: the Burn 2 Learn cluster randomised controlled trial

Introduction: Time-efficient physical activity interventions are needed for older adolescents (≥16 years) in the senior school years (i.e., Grades 11 and 12) where there is a heavy focus on academic performance and physical education is not mandatory. The aim of our study was to evaluate the impact of a time-efficient school-based intervention designed to improve older adolescents’ cardiorespiratory fitness (CRF) by integrating high-intensity activity breaks into curriculum time. Methods: We evaluated the Burn 2 Learn (B2L) intervention using a cluster randomised controlled trial with older adolescents (N=670) from 20 secondary schools in New South Wales, Australia. We utilised a range of implementation strategies to support teachers to facilitate the delivery of 2-3 high intensity interval training (HIIT) sessions/week during lesson-time. The B2L intervention included the following: (i) information seminar for students delivered by school champions, (ii) school-based HIIT sessions delivered during lesson time, (iii) purpose-built smartphone application (app) and heart rate monitors designed to quantify individual and group heart rate and support self-monitoring, and (iv) information newsletters for parents. The HIIT sessions involved a combination of aerobic and muscle-strengthening exercises, designed to be enjoyable and vigorous in nature. Teachers and students in the control group continued with their usual practice. Outcomes were assessed at baseline, 6 and 12-months. The primary outcome was CRF (multi-stage fitness test). Secondary outcomes included physical activity (ActiGraph GT9X Link accelerometers), hair cortisol concentrations, muscular fitness (push-up and standing long jump tests), body composition (body mass index), mental health and HIIT self-efficacy (questionnaires). Data were analysed using linear mixed models, accounting for clustering of effects at the class level. Potential moderators of effects were identified a priori and sub-group analyses were conducted if interaction tests were significant (p<0.1). Results: At the primary endpoint (6-months), we found a significant difference between groups (in favour of B2L) for the primary outcome CRF [4.0 laps (95% CI, 1.7 to 6.4)] and a range of secondary outcomes. Moderator analyses revealed reduced stress and internalising problems among adolescents in the intervention group who were identified as ‘at-risk’ of poor mental health at baseline. Discussion: Implementing high intensity breaks during curricular time improved CRF and muscular endurance among the full sample of older adolescents, and mental health among the ‘at-risk’ sub-sample. Our findings highlight the health benefits of re-allocating a small amount of curriculum time to physical activity during the final years of secondary school. Trial registration: ACTRN12618000293268 My co-authors and I acknowledge that we have no conflicts of interest of relevance to the submission of this abstract.

Sex Moderates The Associations Of Accelerometer-measured Physical Activity Intensity To Executive Functions Among Older Adolescents

Physical activity (PA) of sufficient intensity to improve aerobic fitness is associated with enhanced executive functions (EFs) in preadolescents. However, the relationship between PA intensity and EFs among older adolescents and the effect of sex on these associations remain poorly understood. PURPOSE: To examine the moderating effects of sex on the relationship between accelerometer-measured PA (volume, intensity) and EFs (inhibitory control, working memory) in 15-18 years old adolescents. METHODS: We analyzed baseline data from 417 participants (210 [50%] females, Mage = 16.5 ± 0.40 yrs, BMI = 23.2 ± 4.30 kg/m2) from the Burn 2 Learn cluster randomized controlled trial. Adolescents wore Actigraph GT9X Link accelerometers on their non-dominant wrist for 7 days, 24-h·d-1. Accelerometer metrics included average raw accelerations over 5 s epochs (AvgAcc), intensity gradient (IG; the slope of the log-log regression line of intensity over time; higher IG indicates higher intensity), and moderate-to-vigorous PA (MVPA) using Hildebrand youth cut-points. Inhibitory control was expressed as accuracy, reaction time (RT), and variability of the RT (standard deviation; SDRT) on incongruent trials of a modified Eriksen flanker task. Working memory (WM) was expressed as a d prime (d’) index on the 2-back task (z-scoretarget accuracy - z-scorefalse alarms). Multi-level random intercept models, accounting for clustering within schools, were used to test the moderating effects of sex on the PA-EF relationship, adjusting for age, BMI, and aerobic fitness. RESULTS: Sex moderated the relationship between IG and incongruent SDRT (b = 0.16, 95% CI: 0.04, 0.28, P = 0.01), and IG and the d’ index (b = -0.29, 95% CI: -0.47, -0.11, P = 0.002) even after controlling for AvgAcc. Girls with higher IG showed less variability in incongruent RT (b = -0.16, 95% CI: -0.25, -0.06; boys: Ps ≥ 0.68) and higher d’ index (b = 0.25, 95% CI: 0.11, 0.40; boys: Ps ≥ 0.21). In contrast, AvgAcc was not related to inhibitory control (Ps ≥ 0.06) or WM (Ps ≥ 0.21) after adjusting for IG. MVPA was not related to inhibitory control or WM (Ps ≥ 0.20). CONCLUSIONS: Our findings reveal a novel selective association between PA intensity and EFs among older adolescent girls. Girls with higher intensity profiles showed superior performance across two EF tasks.

Comparison Between Dance-based Exergaming And Aerobic Dance On Young Adults’ Physiological And Psychological Outcomes

PURPOSE: In order to better develop effective physical activity programs among young adults, this study explored the effects of a dance-based exergaming on Chinese college students’ energy expenditure, enjoyment, and self-efficacy in comparison with the traditional aerobic dance exercise. METHODS: A one-group repeated-measures design was used for this study. A total of 40 college students (33 females; Mage = 21.16 years, SD = 2.1) completed two separate 20-minutes exercise sessions with a 10-minute interval on the same day: (1) Xbox 360 Kinect Just Dance exergaming session; and (2) traditional instructor-led aerobic dance exercise session. Participants’ energy expenditure (kcal/day) was measured by the ActiGraph GT9X Link accelerometers, and their perceived enjoyment and self-efficacy were assessed via validated surveys following each session. The dependent t-test was used to examine the mean differences for all outcomes between two sessions, with the significance level set at 0.05. RESULTS: Dependent t-test indicated significant differences on participants’ enjoyment (t = -1.83, p = 0.04, Cohen’s d = 0.30). Specifically, participants in the dance-based exergaming session reported higher level of enjoyment (M = 3.96, SD = 0.65) as compared to aerobic dance session (M = 3.61, SD = 0.54). However, there was no significant difference for energy expenditure (M1 = 106.76 VS M2 = 104.14) and self-efficacy (M1 = 4.06 VS M2 = 3.95) between two sessions. CONCLUSIONS: The findings suggested that, in dance-based exergaming play session, college students had comparable energy expenditure as the traditional aerobic dance session while experiencing more fun and enjoyment. This suggests that exergaming can be a fun exercise alternative for promoting physical activity among young adults. Future randomized control trials are needed to further conclude the effects of exergaming among this population.

Walking to/from school is strongly associated with physical activity before and after school and whole-day in schoolchildren: A pilot study

BackgroundFew studies with children in Asian countries, especially in Japan, have examined the relationship between walking to/from school and physical activity by segments of the day. Therefore, the present study examined the associations between walking to/from school with physical activity before school, after school, and during the entire day in a sample with a high proportion of Japanese children who walk to/from school. MethodsA total of 119 participants (10.4 ± 1.3 years old) were investigated regarding their mode and length of school commute and physical activity. Step counts, sedentary time (ST), light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) were measured using an ActiGraph GT9X Link accelerometer. The associations between time walking to/from school and physical activity were analyzed using the Spearman correlation coefficient. A receiver-operating characteristic analysis was used to identify the threshold of the time spent walking to/from school that is necessary to meet the physical activity guideline (MVPA ≥ 60 min/day). ResultsThe results showed that 90.8% and 89.9% of students walked to/from school, respectively. The segments of before school, after school, before and after school, and during the entire day demonstrated significant low to high (r = 0.20–0.86) correlations between the time spent walking to/from school and step counts, ST, LPA, and MVPA. Our study showed that spending ≥45 min walking to/from school is important for meeting the physical activity recommendations. ConclusionsThis study provides important evidence for the promotion of walking to/from school in the future. In addition, our results also suggested that children with relatively short commuting time to school need to be more physically active in daily life situations.

Relationships between College Students' Sedentary Behavior, Sleep Quality, and Body Mass Index.

Purpose: Sedentary behavior (SB), sleep efficiency (SE), sleep duration (SD), and body mass index (BMI) are crucial determinants of an individual’s health. However, empirical evidence regarding associations between these factors in young adults living in China remains unknown. Therefore, the purpose of this study was to examine the relationships between accelerometer-measured SB, SE, SD, and BMI in Chinese college students. Methods: Two-hundred and twenty college students (115 females, Meanage = 20.29 years, SD = 2.37) were recruited from a south-central Chinese university. Participants’ SB (daily % time spent in SB), SE (number of minutes of sleep duration/number of minutes in bed), and SD were assessed via wrist-worn ActiGraph GT9X Link accelerometers for one week. Body weight was measured using a digital weight scale, height was measured using a stadiometer, and BMI was calculated as weight (kg)/height (m2). Results: Participants’ average time spent in SB was 76.52% (SD = 10.03), SE was 84.12% (SD = 4.79), and BMI was 20.67 kg/m2 (SD = 3.12), respectively. Regression analyses indicated that SB (β = −0.17, p = 0.01) and BMI (β = −0.20, p < 0.01) negatively predicted SE. In addition, BMI negatively predicted SD (β = −0.22, p < 0.01). Conclusion: Prolonged SB (e.g., screen viewing, smartphone use, and computer playing) and higher BMI may link to shorter sleep duration and lower sleep efficiency in Chinese young adults. Future randomized controlled trials are needed to further confirm these findings. Given that increased BMI status and SB may relate to adverse health outcomes, more population-based intervention strategies seeking to lower BMI and reduce SB (e.g., nutrition education and physical activity promotion) are needed in this population.

Feasibility Study Comparing Physical Activity Classifications from Accelerometers with Wearable Camera Data.

Device-based assessments are frequently used to measure physical activity (PA) but contextual measures are often lacking. There is a need for new methods, and one under-explored option is the use of wearable cameras. This study tested the use of wearable cameras in PA measurement by comparing intensity classifications from accelerometers with wearable camera data. Seventy-eight 18–30-year-olds wore an Actigraph GT9X link accelerometer and Autographer wearable camera for three consecutive days. An image coding schedule was designed to assess activity categories and activity sub-categories defined by the 2011 Compendium of Physical Activities (Compendium). Accelerometer hourly detailed files processed using the Montoye (2020) cut-points were linked to camera data using date and time stamps. Agreement was examined using equivalence testing, intraclass correlation coefficient (ICC) and Spearman’s correlation coefficient (rho). Fifty-three participants contributing 636 person-hours were included. Reliability was moderate to good for sedentary behavior (rho = 0.77), light intensity activities (rho = 0.59) and moderate-to-vigorous physical activity (MVPA) (rho = 0.51). The estimates of sedentary behavior, light activity and MVPA from the two methods were similar, but not equivalent. Wearable cameras are a potential complementary tool for PA measurement, but practical challenges and limitations exist. While wearable cameras may not be feasible for use in large scale studies, they may be feasible in small scale studies where context is important.

Development of cut-points for determining activity intensity from a wrist-worn ActiGraph accelerometer in free-living adults

ABSTRACT Despite recent popularity of wrist-worn accelerometers for assessing free-living physical behaviours, there is a lack of user-friendly methods to characterize physical activity from a wrist-worn ActiGraph accelerometer. Participants in this study completed a laboratory protocol and/or 3–8 hours of directly observed free-living (criterion measure of activity intensity) while wearing ActiGraph GT9X Link accelerometers on the right hip and non-dominant wrist. All laboratory data (n = 36) and 11 participants’ free-living data were used to develop vector magnitude count cut-points (counts/min) for activity intensity for the wrist-worn accelerometer, and 12 participants’ free-living data were used to cross-validate cut-point accuracy. The cut-points were: <2,860 counts/min (sedentary); 2,860–3,940 counts/min (light); and ≥3,941counts/min (moderate-to-vigorous (MVPA)). These cut-points had an accuracy of 70.8% for assessing free-living activity intensity, whereas Sasaki/Freedson cut-points for the hip accelerometer had an accuracy of 77.1%, and Hildebrand Euclidean Norm Minus One (ENMO) cut-points for the wrist accelerometer had an accuracy of 75.2%. While accuracy was higher for a hip-worn accelerometer and for ENMO wrist cut-points, the high wear compliance of wrist accelerometers shown in past work and the ease of use of count-based analysis methods may justify use of these developed cut-points until more accurate, equally usable methods can be developed.

Novel Application Of Accelerometry Data To Enhance Detection Of Falls Risk In Older Adults

PURPOSE: The association between physical activity (PA) and falls is complex and bi-directional, with more active persons often demonstrating greater falls risk. The role of PA in preventing or aggravating falls risk may be illuminated by novel, more sensitive measures of PA. We examined the longitudinal association between accelerometer derived PA metrics and falls in control group participants of STURDY (Study to Understand Fall Reduction and Vitamin D in You), a randomized trial of vitamin D supplementation to prevent falls in older adults. METHODS: PA was assessed at baseline, 12-, and 24-months using the Actigraph Link accelerometer, worn 24-hours per day for 7 days on the non-dominant wrist. Falls were reported using a monthly calendar. Minute level activity counts were examined to derive diurnal patterns of PA and number of active minutes/day in 319 participants (mean age 77 (SD=5.4) years, 43% female). Multiple logistic regression models adjusted for age, sex, and gait speed examined the: i) risk of falls by tertiles of daily PA and ii) risk of falls by demographic and functional characteristics, comparing measures of falls per unit time (year) and falls per unit of activity (active minute). RESULTS: In adjusted models, those in the high and low PA tertiles had 78% and 7% greater odds of falling over the next 12 months compared to those in the moderate PA tertile, respectively (p<.05). Moreover, peak daily PA declined 12% between baseline and 24-month follow-up among fallers vs. 8% among non-fallers (p<.05). Differences in daily PA between fallers and non-fallers tended to be greatest between 8am-12pm. Models comparing risk of falls over 24 months of follow-up demonstrated stronger trends in falls risk at higher ages (80 vs >80), among men, and for those with slower gait speeds (<0.8 m/s vs 0.8m/s) when analyzed per unit of activity (falls/active minute) vs. unit of time (falls/year). CONCLUSION: These results demonstrate a J-shaped association between PA and falls, with stronger differences in PA between fallers and non-fallers during the morning hours. Furthermore, the trend towards more robust results for falls/active minute vs. falls/year highlight the complex nature of the association between PA and falls and suggest that novel PA metrics may serve as more sensitive indicators for discerning falls risk.

Prescribed Physical Activity In Postpartum Period Helps Women Increase Physical Activity And Decrease Body Weight

New mothers frequently report a lack of adequate physical activity (PA) due to a variety of constraints. PA is an important factor in developing and maintaining a healthy lifestyle and may assist new mothers in returning to pre-pregnancy weight. Despite the potential positive impact of PA on new mothers, PA level during the postpartum period is unknown. PURPOSE: To evaluate the impact of a PA intervention in increasing postpartum PA level and weight loss. METHODS: Thirty-two postpartum women (mean age=33±3, mean BMI=27.8±5.6 kg/m2) were randomized into control (n=16) and intervention (n=16) groups. The intervention group was instructed to engage in 150 minutes of MVPA each week and take 10,000 steps per day, the control group was given no physical activity prescription. Measures of body weight and PA (by wrist-worn ActiGraph Link accelerometers worn continuously over 7 days) were made at 3, 6, 9, and 12 months postpartum. PA data was expressed as the vector magnitude of counts (VMC) across the three axes. Differences in PA and body weight between groups over time were examined using two-way ANOVA with repeated measures and Tukey post hoc analysis. RESULTS: The intervention protocol was successful at increasing women’s overall PA during the postpartum period (main effect: 2.9x106±0.4x106 vs. 2.6x106±0.4x106 counts, p<0.05) but the only significant differences in PA by time between groups was at the initial 3 month postpartum visit (2.7x106±0.3x106 vs. 2.4x106±0.4x106 counts, p<0.05) as the intervention did not lead to a further significant increases in PA throughout the remainder of the postpartum period. The control group showed a significant increase in PA from the 3 month to the 12 month visit (2.4x106±0.4x106 vs. 2.8x106±0.4x106 counts, p<0.05), ultimately reaching similar PA to that of the intervention group. Body weight was similar at the initial 3 month visit and decreased significantly in both groups during the postpartum period, however the intervention group had a significantly lower body mass by the end of the postpartum period compared to the control group (70.2±14.8 vs.72.6±16.8 kg, p<0.05). CONCLUSION: Increased PA habits during the postpartum period may help women more successfully return to pre-pregnancy body weight and reduce the risk for overweight or obesity following childbirth.

Effects of Proximity between Companion Dogs and Their Caregivers on Heart Rate Variability Measures in Older Adults: A Pilot Study.

Heart rate variability (HRV) is a noninvasive tool used to evaluate autonomic nervous system function and is affected by age, stress, postural changes, and physical activity. Dog ownership has been associated with higher 24-hr HRV and increased physical activity compared to nonowners. The current pilot study was designed to evaluate the effects of proximity to a dog in real time (minute-by-minute) on older dog caregivers’ HRV measures and stress index during normal daily life over a 24-hr period. Eleven caregivers (56–83 years of age) wore ActiGraph GT9X Link accelerometers and camntech electrocardiogram monitors, and 11 dogs wore PetPace Collars and ActiGraph monitors to determine (a) proximity (absence or presence of Received Signal Strength Indicator, RSSI), (b) heart rate and HRV measures, (c) position (lying vs. sitting vs. standing), and (d) physical activity in the 11 dyads. Twenty-four hour HRV (SDNN index) and physical activity in the caregivers and dogs were related. Stress index was lower, and HRV parameters (SDNN, rMSDD, high frequency power (HF)) were higher when an RSSI signal was detected (presence of dog) compared to no RSSI signal (absence of dog) in the caregivers while inactive (lying + sitting + standing combined). HRV parameters (rMSDD and HF) were lower in the caregivers while standing and sitting compared to lying. The results from this pilot study support the hypothesis that spending time in the presence of a companion dog increases caregivers’ HRV throughout the day and suggest that proximity to a dog may contribute to overall improvements in 24-hr HRV and cardiac health in dog caregivers.

Combining Actigraph Link and PetPace Collar Data to Measure Activity, Proximity, and Physiological Responses in Freely Moving Dogs in a Natural Environment.

Simple SummaryThe Actigraph accelerometry monitors, the most widely used and extensively validated devices for measuring physical activity in humans, have also been validated for use in dogs. The ActiGraph GT9X Link monitor has Bluetooth Smart technology and a proximity-tagging feature that potentially allows for the measurement of distance between subjects, e.g., between human caretakers and their dog(s). The PetPace Smart-collar is a non-invasive wireless collar that collects important health markers, including heart beats, variation in the intervals between heartbeats, breaths per minute, and position data (lying, sitting, standing), in addition to activity. The purpose of this study was to determine whether combining data from the Actigraph monitor and PetPace collar would provide reliable pulse, respiration, and heart rate variability results during various activity levels in dogs, and whether these variables were affected by the absence or presence of their caretakers.Although several studies have examined the effects of an owner’s absence and presence on a dog’s physiological responses under experimental conditions over short periods of time (minutes), little is known about the effects of proximity between humans and freely moving dogs under natural conditions over longer periods of time (days). The first aim of our study was to determine whether the combined data generated from the PetPace Collar and Actigraph Link accelerometer provide reliable pulse, respiration, and heart rate variability results during sedentary, light-moderate, and vigorous bouts in 11 freely moving dogs in a foster caretaker environment over 10–15 days. The second aim was to determine the effects of proximity (absence and presence of caretaker) and distance (caretaker and dog within 0–2 m) on the dogs’ physiological responses. Aim 1 results: Pulse and respiration were higher during light-moderate bouts compared to sedentary bouts, and higher at rest while the dogs were standing and sitting vs. lying. Heart rate variability (HRV) was not different between activity levels or position. Aim 2 results: During sedentary bouts, pulse and respiration were higher, and HRV lower, when there was a proximity signal (caretaker present) compared to no proximity signal (caretaker absent). Using multiple regression models, we found that activity, position, distance, and signal presence were predictors of physiological response in individual dogs during sedentary bouts. Our results suggest that combining data collected from Actigraph GT9X and PetPace monitors will provide useful information, both collectively and individually, on dogs’ physiological responses during activity, in various positions, and in proximity to their human caretaker.