Effectiveness of workplace interventions with digital elements to reduce sedentary behaviours in office employees: a systematic review and meta-analysis.

BACKGROUND: Digital interventions are potential tools for reducing and limiting occupational sedentary behaviour (SB) in sedentary desk-based jobs. Given the harmful effects of sitting too much and sitting for too long while working, the aim of this systematic review and meta-analysis was to examine the effectiveness of workplace interventions, that incorporated digital elements, to reduce the time spent in SB in office workers. METHODS: Randomised control trials that evaluated the implementation of workplace interventions that incorporated digital elements for breaking and limiting SB among desk-based jobs were identified by literature searches in six electronic databases (PubMed, Web of Science, Scopus, CINAHL, PsycINFO and PEDro) published up to 2023. Studies were included if total and/or occupational SB were assessed. Only studies that reported pre- and postintervention mean differences and standard deviations or standard errors for both intervention arms were used for the meta-analysis. The meta-analysis was conducted using Review Manager 5 (RevMan 5; Cochrane Collaboration, Oxford, UK). Risk of bias was assessed using the Standard Quality Assessment Criteria for Evaluating Primary Research Papers from a Variety of Fields QUALSYST tool. RESULTS: Nineteen studies were included in the systematic review. The most employed digital elements were information delivery and mediated organisational support and social influences. Multicomponent, information, and counselling interventions measuring total and/or occupational/nonoccupational SB time by self-report or via device-based measures were reported. Multicomponent interventions were the most represented. Eleven studies were included in the meta-analysis, which presented a reduction of 29.9 (95% CI: -45.2, -14.5) min/8 h workday in SB (overall effect: Z = 3.81). CONCLUSIONS: Multicomponent interventions, using a wide range of digital features, have demonstrated effectiveness in reducing time spent in SB at the workplace among desk-based employees. However, due to hybrid work (i.e., work in the office and home) being a customary mode of work for many employees, it is important for future studies to assess the feasibility and effectiveness of these interventions in the evolving work landscape. TRIAL REGISTRATION: The review protocol was registered in the Prospero database (CRD42022377366).

A Standardised Core Outcome Set for Measurement and Reporting Sedentary Behaviour Interventional Research: The CROSBI Consensus Study.

Heterogeneity of descriptors and outcomes measured and reported in sedentary behaviour (SB) research hinder the meta-analysis of data and accumulation of evidence. The objective of the Core Research Outcomes for Sedentary Behaviour Interventions (CROSBI) consensus study was to identify and validate, a core outcome set (COS) to report (what, how, when to measure) in interventional sedentary behaviour studies. Outcomes, extracted from a systematic literature review, were categorized into domains and data items (COS v0.0). International experts (n = 5) provided feedback and identified additional items, which were incorporated into COS v0.1. A two round online Delphi survey was conducted to seek consensus from a wider stakeholder group and outcomes that achieved consensus in the second round COS (v0.2), were ratified by the expert panel. The final COS (v1.0) contains 53 data items across 12 domains, relating to demographics, device details, wear-time criteria, wear-time measures, posture-related measures, sedentary breaks, sedentary bouts and physical activity. Notably, results indicate that sedentary behaviour outcomes should be measured by devices that include an inclinometry or postural function. The proposed standardised COS is available openly to enhance the accumulation of pooled evidence in future sedentary behaviour intervention research and practice.

The Influence of Sitting, Standing, and Stepping Bouts on Cardiometabolic Health Markers in Older Adults.

Aside from total time spent in physical activity behaviors, how time is accumulated is important for health. This study examined associations between sitting, standing, and stepping bouts, with cardiometabolic health markers in older adults. Participants from the Mitchelstown Cohort Rescreen Study (N = 221) provided cross-sectional data on activity behaviors (assessed via an activPAL3 Micro) and cardiometabolic health. Bouts of ≥10-, ≥30-, and ≥60-min sitting, standing, and stepping were calculated. Linear regression models were fitted to examine the associations between bouts and cardiometabolic health markers. Sitting (≥10, ≥30, and ≥60 min) and standing (≥10 and ≥30 min) bouts were detrimentally associated with body composition measures, lipid markers, and fasting glucose. The effect for time spent in ≥60-min sitting and ≥30-min standing bouts was larger than shorter bouts. Fragmenting sitting with bouts of stepping may be targeted to benefit cardiometabolic health. Further insights for the role of standing need to be elicited.

Seasonal changes in the physical activity levels of youth Gaelic football players.

This study quantified changes in physical activity (PA) levels attained by adolescents during Gaelic football (GF) participation across two time points in a season and determined if these changes affected their overall daily PA levels. A total of 130 adolescents (65 females;15.3 ± 1.5 years) wore an activPAL accelerometer to determine total moderate PA (MPA), vigorous PA (VPA) and moderate-to-vigorous PA (MVPA) during a seven-day measurement period, including during GF. The PA measurement was completed at "preseason" (T1) and "in-season" (T2) timepoints. Between T1 and T2, females significantly increased time spent in MVPA daily (p < 0.001, d = 0.95), on Gaelic football days (GFDs) (p = 0.036; d = 0.30), on non-Gaelic football days (NGFDs) (p < 0.001; d = 0.43), and during GF (p < 0.001, d = 0.90). Males did not record any significant changes in PA over time (p > 0.05). At T2, there were no significant differences in time spent in MVPA daily, on GFDs and NGFDs, and during GF between the genders (p > 0.05). The results suggest that the change in daily PA levels by females is a consequence of increased MVPA during GF and reduced PA barriers across the season.

The Contribution of Gaelic Football Participation to Youth Physical Activity Levels.

The primary aim of this study was to describe the contribution of Gaelic football participation to youth physical activity (PA) levels. Secondary aims were to objectively quantify the overall daily PA levels of participants across sex and age, to determine the PA levels achieved during Gaelic football practice sessions and games, and to compare PA levels on days with organized sporting activity (sports days) and days without organized sporting activity (non-sports days). One hundred and sixty adolescents (87 male, 73 female; mean age 14.5 ± 1.8 yrs.) wore an activPAL accelerometer to determine total sitting/lying time, standing time, light intensity physical activity (LIPA), moderate physical activity (MPA), vigorous physical activity (VPA) and moderate-to-vigorous physical activity (MVPA) during a seven day measurement period, including during Gaelic football participation. Participants achieved an average of 58.5 ± 23.6 minutes of MVPA daily. Males accumulated significantly more MVPA daily than females (Males=70.8±22.1 min; Females = 45.5 ± 16.5 min; p < 0.001; ηp² = 0.401) and time spent in MVPA daily significantly decreased with age (p < 0.001; ηp² = 0.299). Participants accumulated significantly more MVPA during games (36.0 ± 9.2 min/hr (60%)) than practice sessions (29.0 ± 8.3 min/hr (48%); p < 0.001; d = 0.80). On sports days, participants accumulated significantly more time in MVPA (Sports Days = 70.1 ± 36.0 min; Non-Sports Days = 54.2 ± 34.0; p < 0.001; d = 0.45) and were 2.16 times more likely to achieve 60 minutes of MVPA (OR = 2.16; 95% CI = 1.60-2.92) than on non-sports days. The results reveal that Gaelic football provides an opportunity for adolescents to accumulate PA, however, participants currently spent more than 50% of their practice time inactive or in low intensity activities. An opportunity remains to enhance the contribution of Gaelic football to overall daily PA levels, by replacing time spent inactive with time in MVPA.

Monitoring Occupational Sitting, Standing, and Stepping in Office Employees With the W@W-App and the MetaWearC Sensor: Validation Study.

BACKGROUND: Replacing occupational sitting time with active tasks has several proposed health benefits for office employees. Mobile phones and motion sensors can provide objective information in real time on occupational sitting behavior. However, the validity and feasibility of using mobile health (mHealth) devices to quantify and modify occupational sedentary time is unclear. OBJECTIVE: The aim of this study is to validate the new Walk@Work-Application (W@W-App)-including an external motion sensor (MetaWearC) attached to the thigh-for measuring occupational sitting, standing, and stepping in free-living conditions against the activPAL3M, the current gold-standard, device-based measure for postural behaviors. METHODS: In total, 20 office workers (16 [80%] females; mean age 39.5, SD 8.1 years) downloaded the W@W-App to their mobile phones, wore a MetaWearC sensor attached to their thigh using a tailored band, and wore the activPAL3M for 3-8 consecutive working hours. Differences between both measures were examined using paired-samples t tests and Wilcoxon signed-rank tests. Agreement between measures was examined using concordance correlation coefficients (CCCs), 95% CIs, Bland-Altman plots (mean bias, 95% limits of agreement [LoA]), and equivalence testing techniques. RESULTS: The median recording time for the W@W-App+MetaWearC and the activPAL3M was 237.5 (SD 132.8) minutes and 240.0 (SD 127.5) minutes, respectively (P<.001). No significant differences between sitting (P=.53), standing (P=.12), and stepping times (P=.61) were identified. The CCC identified substantial agreement between both measures for sitting (CCC=0.98, 95% CI 0.96-0.99), moderate agreement for standing (CCC=0.93, 95% CI 0.81-0.97), and poor agreement for stepping (CCC=0.74, 95% CI 0.47-0.88). Bland-Altman plots indicated that sitting time (mean bias -1.66 minutes, 95% LoA -30.37 to 20.05) and standing time (mean bias -4.85 minutes, 95% LoA -31.31 to 21.62) were underreported. For stepping time, a positive mean bias of 1.15 minutes (95% LoA -15.11 to 17.41) was identified. Equivalence testing demonstrated that the estimates obtained from the W@W-App+MetaWearC and the activPAL3M were considered equivalent for all variables excluding stepping time. CONCLUSIONS: The W@W-App+MetaWearC is a low-cost tool with acceptable levels of accuracy that can objectively quantify occupational sitting, standing, stationary, and upright times in real time. Due to the availability of real-time feedback for users, this tool can positively influence occupational sitting behaviors in future interventions. TRIAL REGISTRATION: ClinicalTrials.gov NCT04092738; https://clinicaltrials.gov/ct2/show/NCT04092738.

Use of Compositional Data Analysis to Show Estimated Changes in Cardiometabolic Health by Reallocating Time to Light-Intensity Physical Activity in Older Adults.

BACKGROUND: All physical activity (PA) behaviours undertaken over the day, including sleep, sedentary time, standing time, light-intensity PA (LIPA) and moderate-to-vigorous PA (MVPA) have the potential to influence cardiometabolic health. Since these behaviours are mutually exclusive, standard statistical approaches are unable to account for the impact on time spent in other behaviours. OBJECTIVE: By employing a compositional data analysis (CoDA) approach, this study examined the associations of objectively measured time spent in sleep, sedentary time, standing time, LIPA and MVPA over a 24-h day on markers of cardiometabolic health in older adults. METHODS: Participants (n =366; 64.6 years [5.3]; 46% female) from the Mitchelstown Cohort Rescreen Study provided measures of body composition, blood lipid and markers of glucose control. An activPAL3 Micro was used to obtain objective measures of sleep, sedentary time, standing time, LIPA and MVPA, using a 7-day continuous wear protocol. Regression analysis, using geometric means derived from CoDA (based on isometric log-ratio transformed data), was used to examine the relationship between the aforementioned behaviours and markers of cardiometabolic health. RESULTS: Standing time and LIPA showed diverging associations with markers of body composition. Body mass index (BMI), body mass and fat mass were negatively associated with LIPA (all p <0.05) and positively associated with standing time (all p <0.05). Sedentary time was also associated with higher BMI (p <0.05). No associations between blood markers and any PA behaviours were observed, except for triglycerides, which were negatively associated with standing time (p < 0.05). Reallocating 30 min from sleep, sedentary time or standing time, to LIPA, was associated with significant decreases in BMI, body fat and fat mass. CONCLUSION: This is the first study to employ CoDA in older adults that has accounted for sleep, sedentary time, standing time, LIPA and MVPA in a 24-h cycle. The findings support engagement in LIPA to improve body composition in older adults. Increased standing time was associated with higher levels of adiposity, with increased LIPA associated with reduced adiposity; therefore, these findings indicate that replacing standing time with LIPA is a strategy to lower adiposity.

Tracking of Physical Activity and Sedentary Behavior From Adolescence to Young Adulthood: A Systematic Literature Review.

PURPOSE: The transition from adolescence to young adulthood is categorized by substantial changes in one's activity behaviors, which may have important implications for health. To date, no reviews have systematically investigated the evidence of tracking for both physical activity (PA) and sedentary behavior (SB) specifically during this transition period. METHODS: Web of Science, PubMed, SPORTDiscus, PsycINFO, and CINAHL were searched for articles that examined the tracking of PA and SB in adolescents (aged 9-18 years) through young adulthood (aged 19-25 years) published between the years of 2000 and 2018. Studies were also compared on methodologic quality. RESULTS: Sixteen studies met the inclusion criteria. The tracking correlations for both the frequency and duration of PA were low-to-moderate. Gender differences were observed in the tracking of PA frequency and duration. Studies that examined the tracking of SB were less frequent, making it difficult to determine how SB tracks from adolescence to young adulthood. CONCLUSIONS: Generally, PA was shown to track moderately from adolescence through young adulthood. The lack of studies reporting on the tracking of SB indicates that this area should be a target for future research. Future tracking studies should consider appropriate gold-standard objective methodologies and statistical analysis techniques that report fixed outcomes.

Validation study of the Spanish version of the Last-7-d Sedentary Time Questionnaire (SIT-Q-7d-Sp) in young adults.

There are few valid instruments to assess domain-specific sedentary behaviours (SB) among Spanish-speaking populations. This study validated the original English version of the last 7 days SB questionnaire (SIT-Q-7d) into Spanish (Castilian). A total of 151 undergraduates (52% male, 21.19±2.57 yrs.) wore an activPAL3M (AP3M) for 7 days and subsequently completed the Spanish version of the SIT-Q-7d (SIT-Q-7d-Sp). A subsample of 30 participants (70% male, 22.89±1.54 yrs.) simultaneously wore the AP3M and used a domain-log to register the context where the SB occurred. The SIT-Q-7d-Sp differed significantly from the AP3M, overestimating sitting time by an average of 60.69 mins.d-1 (all p<0.016). No significant differences were observed between the two measures for weekend total sitting time. The SIT-Q-7d-Sp did not differ significantly from the AP3M +Log for meal, work, and transportation-based sitting time (all p>0.016). However, screen-based and other leisure-based sitting activities were significantly overestimated (ranging from 94.68 mins.d-1 to 234.08 mins.d-1, p<0.001). The SIT-Q-7d-Sp appears to provide acceptable estimates of sitting time during transportation, occupational and meal-based domains. The SIT-Q-7d-Sp is not an appropriate measure of SB when examining total sitting time and leisure-based SB in young adults. For total sitting time and leisure-based SB, the use of objective measures is recommended.

ActivPAL™ determined sedentary behaviour, physical activity and academic achievement in college students.

The aim of this study was to examine relationships between activPAL™-determined sedentary behavior (SB) and physical activity (PA) with academic achievement. A total of 120 undergraduates (N = 57 female; 20.6 ± 2.3 years) participated in the study. Academic achievement was measured as the grade point average obtained from all completed courses. Participants wore on the right tight an activPAL™ for 7 days to determine total sedentary time, total number of sedentary breaks, sedentary bouts, standing time, light and moderate-to-vigorous physical activity (MVPA). Separate multiple linear regression models were performed to examine associations between SB variables and academic achievement. Light PA, MVPA, total sedentary time, total standing time, or total number of sedentary breaks were not related to academic achievement. Independently of PA, the amount of time spent in sedentary bouts of 10-20min during weekdays was positively related to academic achievement. Given that college students spend the majority of their workday in environments that encourage prolonged sitting, these data suggest that interruptions in prolonged periods of sitting time every 10-20min via short breaks may optimize cognitive operations associated with academic performance.

A systematic literature review of reviews on techniques for physical activity measurement in adults: a DEDIPAC study.

The links between increased participation in Physical Activity (PA) and improvements in health are well established. As this body of evidence has grown, so too has the search for measures of PA with high levels of methodological effectiveness (i.e. validity, reliability and responsiveness to change). The aim of this "review of reviews" was to provide a comprehensive overview of the methodological effectiveness of currently employed measures of PA, to aid researchers in their selection of an appropriate tool. A total of 63 review articles were included in this review, and the original articles cited by these reviews were included in order to extract detailed information on methodological effectiveness.Self-report measures of PA have been most frequently examined for methodological effectiveness, with highly variable findings identified across a broad range of behaviours. The evidence-base for the methodological effectiveness of objective monitors, particularly accelerometers/activity monitors, is increasing, with lower levels of variability observed for validity and reliability when compared to subjective measures. Unfortunately, responsiveness to change across all measures and behaviours remains under-researched, with limited information available.Other criteria beyond methodological effectiveness often influence tool selection, including cost and feasibility. However, researchers must be aware of the methodological effectiveness of any measure selected for use when examining PA. Although no "perfect" tool for the examination of PA in adults exists, it is suggested that researchers aim to incorporate appropriate objective measures, specific to the behaviours of interests, when examining PA in free-living environments.

Minimum Wear Duration for the activPAL Professional Activity Monitor in Adolescent Females.

OBJECTIVES: This study aims to determine the minimum number of days of monitoring required to reliably predict sitting/lying time, standing time, light intensity physical activity (LIPA), moderate-to-vigorous intensity physical activity (MVPA) and steps in adolescent females. METHOD: 195 adolescent females (mean age = 15.7 years; SD = 0.9) participated in the study. Participants wore the activPAL activity monitor for a seven day protocol. The amount of time spent sitting/lying, standing, in LIPA and in MVPA and the number of steps per day were quantified. Spearman-Brown Prophecy formulae were used to predict the number of days of data required to achieve an intraclass correlation coefficient of both 0.7 and 0.8. RESULTS: For the percentage of the waking day spent sitting/lying, standing, in LIPA and in MVPA, a minimum of 9 days of accelerometer recording is required to achieve a reliability of ≥ 0.7, while a minimum of 15 days is required to achieve a reliability of ≥ 0.8. For steps, a minimum of 12 days of recording is required to achieve a reliability of ≥ 0.7, with 21 days to achieve a reliability of ≥ 0.8. CONCLUSION: Future research in adolescent females should collect a minimum of 9 days of accelerometer data to reliably estimate sitting/lying time, standing time, LIPA and MVPA, while 12 days is required to reliably estimate steps.

Results From Ireland North and South's 2016 Report Card on Physical Activity for Children and Youth.

BACKGROUND: Physical activity (PA) is a key performance indicator for policy documents in both the Republic of Ireland and Northern Ireland. Building on baseline grades set in 2014, Ireland's second Report Card on Physical Activity for Children and Youth allows for continued surveillance of indicators related to PA in children and youth. METHODS: Data and information were extracted and collated for 10 indicators and graded using an international standardized grading system. RESULTS: Overall, 7 grades stayed the same, 2 increased, and 1 decreased. Grades were assigned as follows: Overall PA, D (an increase); Sedentary Behavior (TV), C-; Physical Education, D-; Active Play, Incomplete/Inconclusive (INC); Active Transportation, D; School, D (a decrease); Home (Family), INC; Community and the Built Environment, B+ (an increase); and Government, INC. Unlike 2014's report card, different grades for the Republic (C-) and Northern Ireland (C+) were assigned for Organized Sport Participation. CONCLUSIONS: Although the grade for Overall PA levels increased to a D, this may reflect the increased quality and quantity of data available. The double burden of low PA and high sedentary levels are concerning and underscore the need for advocacy toward, and surveillance of, progress in achieving targets set by the new National Physical Activity Plan in the Republic and obesity and sport plans in the North.

The accuracy of the SenseWear Pro3 and the activPAL3 Micro devices for measurement of energy expenditure.

Activity monitors such as the SenseWear Pro3 (SWP3) and the activPAL3 Micro (aP3M) are regularly used by researchers and practitioners to provide estimates of the metabolic cost (METs) of activities in free-living settings. The purpose of this study is to examine the accuracy of the MET predictions from the SWP3 and the aP3M compared to the criterion standard MET values from indirect calorimetry. Fifty-six participants (mean age: 39.9 (±11.5), 25M/31F) performed eight activities (four daily living, three ambulatory and one cycling), while simultaneously wearing a SWP3, aP3M and the Cosmed K4B2 (K4B2) mobile metabolic unit. Paired samples T-tests were used to examine differences between device predicted METs and criterion METs. Bland-Altman plots were constructed to examine the mean bias and limits of agreement for predicted METs compared to criterion METs. SWP3 predicted MET values were significantly different from the K4B2 for each activity (p ⩽ 0.004), excluding sweeping (p = 0.122). aP3M predicted MET values were significantly different (p < 0.001) from the K4B2 for each activity. When examining the activities collectively, both devices underestimated activity intensity (0.20 METs (SWP3), 0.95 METs (aP3M)). The greatest mean bias for the SWP3 was for cycling (-3.25 METs), with jogging (-5.16 METs) producing the greatest mean bias for the aP3M. All of the activities (excluding SWP3 sweeping) were significantly different from the criterion measure. Although the SWP3 predicted METs are more accurate than their aP3M equivalent, the predicted MET values from both devices are significantly different from the criterion measure for the majority of activities.

The association between maternal perceptions of own weight status and weight status of her child: results from a national cohort study.

OBJECTIVES: To examine the relationship between maternal self-reported and measured height and weight, maternal perceived weight status and measured body mass index (BMI), and maternal perceived child weight status and measured child BMI. SETTING AND DESIGN: Population-representative National Longitudinal Study of Children Growing Up in Ireland. METHODS: Height and weight of 7655 mothers and their 9-year-old children were objectively measured using standard measurement techniques. Mothers' perceptions of their own weight status and the weight status of their child were reported. The association between accurate perceptions of the mother for herself and her child was tested. RESULTS: Mothers overestimated their height by a mean of 0.5 cm (SD=2.9), underestimated their weight by a mean of 1.4 kg (SD=3.8), consequently underestimating their BMI by a mean of 0.6 kg/m(2) (SD=1.7). The majority (60%) of obese mothers correctly categorised their own weight status. Only 17% of mothers of obese children correctly categorised the weight status of their child. Overweight/obese mothers who correctly categorised their own weight status were more likely to correctly categorise their overweight/obese child compared with those who incorrectly categorised their own weight status (44% vs 23%, 95% CI for difference 13% to 28%, p<0.001 for girls; 37% vs 27%, 95% CI 2% to 18%, p=0.02 for boys; significantly greater difference for girls compared with boys, p=0.04). CONCLUSIONS: Maternal perceptions of their own weight status tend to be more accurate than maternal perceptions of their overweight or obese child. Overweight/obese mothers who correctly categorised their own weight status were more likely to correctly categorise their overweight/obese child.

Light-intensity physical activity is associated with adiposity in adolescent females.

INTRODUCTION: Sedentary behavior (SB) research has relied on accelerometer thresholds to distinguish between sitting/lying time (SLT) and light-intensity physical activity (LIPA). Such methods may misclassify SLT, standing time (StT), and LIPA. This study examines the association between directly measured SB, physical activity (PA), and adiposity in an adolescent female sample. METHODS: Female adolescents (n = 195; mean age, 15.7 yr (SD, 0.9)) had body mass index (BMI) (median, 21.7 kg·m (interquartile range, 5.2 kg·m)) and four-site sum of skinfolds (median, 62.0 mm; interquartile range, 37.1 mm) measured and wore an activPAL™ activity monitor for 7 d. SLT, StT, breaks in SLT, and bouts of SLT <30 and ≥30 min were determined from activPAL outputs. A threshold of 2997 counts per 15 s determined moderate-to-vigorous PA. All remaining time was quantified as LIPA. Mixed linear regression models examined associations between PA variables, SB variables, and adiposity. RESULTS: Participants spent a mean of 65.3% (SD, 7.1) of the waking day in SLT, 23.0% (SD, 5.3) in StT, 5.6% (SD, 1.5) in LIPA, and 6.1% (SD, 2.4) in moderate-to-vigorous PA. Significant effects for the percentage of LIPA (which excluded StT) with both BMI (ß = -4.38, P = 0.0006) and sum of skinfolds (ß = -4.05, P = 0.006) were identified. Significant effects for breaks in SLT with BMI (ß = -0.30, P = 0.04) were also observed. No additional significant associations were found between activity measures and adiposity. CONCLUSIONS: Increased LIPA (excluding StT) and breaks in SLT were negatively associated with adiposity in this sample, independent of age. Interventional work should examine whether reducing SLT through breaks and increasing LIPA may prevent increases in adiposity in adolescent females.

The measurement of sedentary patterns and behaviors using the activPAL™ Professional physical activity monitor.

Epidemiological studies have associated the negative effects of sedentary time and sedentary patterns on health indices. However, these studies have used methodologies that do not directly measure the sedentary state. Recent technological developments in the area of motion sensors have incorporated inclinometers, which can measure the inclination of the body directly, without relying on self-report or count thresholds. This paper aims to provide a detailed description of methodologies used to examine a range of relevant variables, including sedentary levels and patterns from an inclinometer-based motion sensor. The activPAL Professional physical activity logger provides an output which can be interpreted and used without the need for further processing and additional variables were derived using a custom designed MATLAB® computer program. The methodologies described have been implemented on a sample of 44 adolescent females, and the results of a range of daily physical activity and sedentary variables are described and presented. The results provide a range of objectively measured and objectively processed variables, including total time spent sitting/lying, standing and stepping, number and duration of daily sedentary bouts and both bed hours and non-bed hours, which may be of interest when making association between physical activity, sedentary behaviors and health indices.

Criterion and concurrent validity of the activPAL™ professional physical activity monitor in adolescent females.

BACKGROUND: The activPAL has been identified as an accurate and reliable measure of sedentary behaviour. However, only limited information is available on the accuracy of the activPAL activity count function as a measure of physical activity, while no unit calibration of the activPAL has been completed to date. This study aimed to investigate the criterion validity of the activPAL, examine the concurrent validity of the activPAL, and perform and validate a value calibration of the activPAL in an adolescent female population. The performance of the activPAL in estimating posture was also compared with sedentary thresholds used with the ActiGraph accelerometer. METHODOLOGIES: Thirty adolescent females (15 developmental; 15 cross-validation) aged 15-18 years performed 5 activities while wearing the activPAL, ActiGraph GT3X, and the Cosmed K4B2. A random coefficient statistics model examined the relationship between metabolic equivalent (MET) values and activPAL counts. Receiver operating characteristic analysis was used to determine activity thresholds and for cross-validation. The random coefficient statistics model showed a concordance correlation coefficient of 0.93 (standard error of the estimate = 1.13). An optimal moderate threshold of 2997 was determined using mixed regression, while an optimal vigorous threshold of 8229 was determined using receiver operating statistics. The activPAL count function demonstrated very high concurrent validity (r = 0.96, p<0.01) with the ActiGraph count function. Levels of agreement for sitting, standing, and stepping between direct observation and the activPAL and ActiGraph were 100%, 98.1%, 99.2% and 100%, 0%, 100%, respectively. CONCLUSIONS: These findings suggest that the activPAL is a valid, objective measurement tool that can be used for both the measurement of physical activity and sedentary behaviours in an adolescent female population.

A steps/minute value for moderate intensity physical activity in adolescent females.

The number of steps/minute (i.e., cadence) that equates to moderate intensity in adolescents is not known. To that end, 31 adolescent females walked on a treadmill at 5 different speeds while wearing an ActivPAL accelerometer and oxygen uptake was recorded by indirect calorimetry. The relationship between metabolic equivalents (METs) and cadence was explored using 3 different analytical approaches. Cadence was a significant predictor of METs (r = .70; p < .001). Moderate intensity (3 METs) corresponded to 94 or 114 steps/minute based on the mixed model and ROC analysis, respectively. These two values, and a practical value of 100 steps/minute, were cross-validated on an independent sample of 33 adolescent females during over-ground walking at 3 speeds. The sensitivity and specificity of each value correctly identifying 3 METs were 98.5% and 87.2% for 94 steps/minute, 72.9% and 98.8 for 114 steps/minute and 96.5% and 95.7% for 100 steps/minute. Compromising on a single cadence of 100 steps/minute would be a practical value that approximates moderate intensity in adolescent females and can be used for physical activity interpretation and promotion.

Cross-sectional analysis of levels and patterns of objectively measured sedentary time in adolescent females.

BACKGROUND: Adolescent females have been highlighted as a particularly sedentary population and the possible negative effects of a sedentary lifestyle are being uncovered. However, much of the past sedentary research is based on self-report or uses indirect methods to quantity sedentary time. Total time spent sedentary and the possible intricate sedentary patterns of adolescent females have not been described using objective and direct measure of body inclination. The objectives of this article are to examine the sedentary levels and patterns of a group of adolescent females using the ActivPAL™ and to highlight possible differences in sedentary levels and patterns across the week and within the school day. A full methodological description of how the data was analyzed is also presented. METHODS: One hundred and eleven adolescent females, age 15-18 yrs, were recruited from urban and rural areas in the Republic of Ireland. Participants wore an ActivPAL physical activity monitor for a 7.5 day period. The ActivPAL directly reports total time spent sitting/lying every 15 seconds and accumulation (frequency and duration) of sedentary activity was examined using a customized MATLAB(®) computer software programme. RESULTS: While no significant difference was found in the total time spent sitting/lying over the full 24 hour day between weekday and weekend day (18.8 vs. 18.9 hours; p = .911), significantly more sedentary bouts of 1 to 5 minutes and 21 to 40 minutes in duration were accumulated on weekdays compared to weekend days (p < .001). The mean length of each sedentary bout was also longer (9.8 vs. 8.8 minutes; p < .001). When school hours (9 am-3 pm) and after school hours (4 pm-10 pm) were compared, there was no difference in total time spent sedentary (3.9 hours; p = .796) but the pattern of accumulation of the sedentary time differed. There were a greater number of bouts of > 20 minutes duration during school hours than after school hours (4.7 vs. 3.5 bouts; p < .001) while after school time consisted of shorter bouts < 20 minutes. CONCLUSIONS: School is highlighted as a particularly sedentary setting for adolescent females. Interventions to decrease sedentary time at school and the use of wearable devices which distinguish posture should be encouraged when examining sedentary patterns and behaviors in this population.