Minimum Wear Time Research Articles

Using Consumer Wearable Devices to Profile Postoperative Complications After Pediatric Appendectomy

IntroductionMarkers of postoperative recovery in pediatric patients are difficult for parents to evaluate after hospital discharge, who use subjective proxies to assess recovery and the onset of complications. Consumer-grade wearable devices (e.g., Fitbit) generate objective recovery data in near real time and thus may provide an opportunity to remotely monitor postoperative patients and identify complications beyond the initial hospitalization. The aim of this study was to use daily step counts from a Fitbit to compare recovery in patients with complications to those without complications after undergoing appendectomy for complicated appendicitis. MethodsChildren ages 3-17 years old undergoing laparoscopic appendectomy for complicated appendicitis were recruited. Patients wore a Fitbit device for 21 d after operation. After collection, patient data were included in the analysis if minimum wear-time criteria were achieved. Postoperative complications were identified through chart review, and step count trajectories for patients recovering with and without complications were compared. Additionally, to account for the patients experiencing a complication on different postoperative days, median daily step count for pre- and post-complication were analyzed. ResultsEighty-six patients with complicated appendicitis were enrolled in the study, and fourteen children developed a postoperative complication. Three patients were excluded because they did not meet the minimum wear time requirements. Complications were divided into abscesses (n = 7, 64%), surgical site infections (n = 2, 18%), and other, which included small bowel obstruction and Clostridioides difficile infection (n = 2, 18%). Patients presented with a complication on mean postoperative day 8, while deviation from the normative recovery trajectory was evident 4 d prior. When compared to children with normative recovery, the patients with surgical complications experienced a slower increase in step count postoperatively, but the recovery trajectory was specific to each complication type. When corrected for day of presentation with complication, step count remained low prior to the discovery of the complication and increased after treatment resembling the normative recovery trajectory. ConclusionsThis study profiled variations from the normative recovery trajectory in patients with complication after appendectomy for complicated appendicitis, with distinct trajectory patterns by complication type. Our findings have potentially profound clinical implications for monitoring pediatric patients postoperatively, particularly in the outpatient setting, thus providing objective data for potentially earlier identification of complications after hospital discharge.

Understanding Physical Behaviors During Periods of Accelerometer Wear and Nonwear in College Students

Accelerometers are increasingly used to measure 24-hr movement behaviors but are sometimes removed intermittently (e.g., for sleep or bathing), resulting in missing data. This study compared physical behaviors between times a hip-placed accelerometer was worn versus not worn in a college student sample. Participants (n = 115) wore a hip-placed ActiGraph during waking times and a thigh-placed activPAL continuously for at least 7 days (mean ± SD 7.5 ± 1.1 days). Thirteen nonwear algorithms determined ActiGraph nonwear; days included in the analysis had to have at least 1 min where the ActiGraph classified nonwear while participant was classified as awake by the activPAL. activPAL data for steps, time in sedentary behaviors (SB), light-intensity physical activity (LPA), and moderate- to vigorous-intensity physical activity (MVPA) from ActiGraph wear times were then compared with activPAL data from ActiGraph nonwear times. Participants took more steps (10.2–11.8 steps/min) and had higher proportions of MVPA (5.0%–5.9%) during ActiGraph wear time than nonwear time (3.1–8.0 steps/min, 0.8%–1.3% in MVPA). Effects were variable for SB (62.6%–66.9% of wear, 45.5%–76.2% of nonwear) and LPA (28.2%–31.5% of wear, 23.0%–53.2% of nonwear) depending on nonwear algorithm. Rescaling to a 12-hr day reduced SB and LPA error but increased MVPA error. Requiring minimum wear time (e.g., 600 min/day) reduced error but resulted in 10%–22% of days removed as invalid. In conclusion, missing data had minimal effect on MVPA but resulted in underestimation of SB and LPA. Strategies like scaling SB and LPA, but not MVPA, may improve physical behavior estimates from incomplete accelerometer data.

Determining minimum number of valid days for accurate estimation of sedentary behaviour and awake-time movement behaviours using the ActivPAL3 in nursing home residents

IntroductionScarce evidence is available about the minimum number of valid days wearing the activPAL3 to obtain a precise estimate of sedentary behaviour (SB) and awake-time movement behaviours (ATMB) in nursing home (NH) residents. The study aimed to determine the minimum number of valid days required for accurately estimate SB and ATMB using the activPAL3 device in NH residents. It also investigated how the starting point of a day (the 24-h period) impacted reliability.MethodsParticipants wore an activPAL3 for 7 consecutive days. The data was classified in two-time blocks (00:00 Ante Meridiem (AM)—00:00 AM midnight vs 12:00 Post Meridiam (PM) -12:00 PM midday) and the sample was stratified into two groups according to their capacity to stand and walk, to examine if timing of sampling or physical functioning affected minimum wear time. SB, ATMB, sociodemographic, and health-related variables were collected. Sensitivity of the time-blocks were tested through the dispersion frequencies and differences between blocks through Kolmogorov–Smirnov test for normality; parametric variables through two-related means T-test and Wilcoxon test for non-parametric data. Reliability was assessed with the Cronbach's Alpha and the intra-class correlation coefficient (ICC), using a one-factor model estimating the reliability for each measurement day loading in the same latent factor.ResultsNinety-five NH residents (81.1% women; age = 85.8 ± 7.2 years) were included. The midnight block had higher reliability, sensitivity and no statistically significant differences between days were found. At least three consecutive days of monitoring were necessary to achieve a reliability of ICC ≥ 0.8 for those NH residents able to stand and walk and six days for those unable.ConclusionsNH residents who are able to stand and walk require a minimum of three consecutive days wearing the device, while those who are unable require at least six days due to their highly homogenous daily routines and sensitivity to PA events. Regardless of the activPAL3 recording start time, data processing should reference the midnight time block.

Recommendations for Identifying Valid Wear for Consumer-Level Wrist-Worn Activity Trackers and Acceptability of Extended Device Deployment in Children

Self-reported physical activity is often inaccurate. Wearable devices utilizing multiple sensors are now widespread. The aim of this study was to determine acceptability of Fitbit Charge HR for children and their families, and to determine best practices for processing its objective data. Data were collected via Fitbit Charge HR continuously over the course of 3 weeks. Questionnaires were given to each child and their parent/guardian to determine the perceived usability of the device. Patterns of data were evaluated and best practice inclusion criteria recommended. Best practices were established to extract, filter, and process data to evaluate device wear, r and establish minimum wear time to evaluate behavioral patterns. This resulted in usable data available from 137 (89%) of the sample. Activity trackers are highly acceptable in the target population and can provide objective data over longer periods of wear. Best practice inclusion protocols that reflect physical activity in youth are provided.

Objectively measured adherence to physical activity among patients with coronary artery disease: Comparison of the 2010 and 2020 World Health Organization guidelines and daily steps.

BackgroundTailored recommendations for patients after percutaneous coronary interventions (PCI) need physical activity (PA) to be objectively measured and assessed for adherence to guidelines. The recent WHO guidelines removed the daily recommended bout duration, while the potential impact of this change on patients after PCI remains unclear.AimWe evaluated prevalence estimates of adherence to PA recommendations among patients after PCI across the 2010 [≥30 min moderate- to vigorous-intensity PA (MVPA) at ≥ 10-min bout duration] and 2020 WHO guidelines (≥30 min of MVPA of any bout duration), as well as 7,500 and 10,000 steps.MethodsWe conducted an observational longitudinal single-center study with patients after PCI for chronic or acute coronary syndrome (ACS); maximal age 80 years. Wrist-worn accelerometers recorded participants’ PA data from the evening of hospital discharge over the next 18 days.ResultsWe analyzed data from 282 participants with sufficient minimum wear time (7 days of ≥12 h), including 45 (16%) women; and 249 (88%) with ACS. Median wear time was 18 (17, 18) days. Median participant age was 62 (55, 69) years. Fifty-two participants (18.4%) fulfilled 2010 WHO guidelines and 226 (80.1%) fulfilled the 2020 WHO guidelines. Further, 209 (74.1%) participants achieved ≥7,500 steps/day and 155 (55.0%) performed ≥10,000 steps/day.ConclusionAmong participants after PCI, most MVPA was accumulated in bouts <10 min, leading to a fourfold discrepancy between participants fulfilling the 2010 and 2020 WHO PA recommendations. The number of steps/day may be a valid proxy to recent WHO PA recommendations as it is not dependent on the bout-length definition.Clinical trial registration[ClinicalTrials.gov], identifier [NCT04663373].

An investigation into the optimal wear time criteria necessary to reliably estimate physical activity and sedentary behaviour from ActiGraph wGT3X+ accelerometer data in older care home residents

BackgroundResearch protocols regarding the use of ActiGraph wGT3X+ accelerometers in care home residents are yet to be established. The purpose of this study was to identify the minimal wear time criteria required to achieve reliable estimates of physical activity (PA) and sedentary behaviour (SB) in older care home residents.MethodsNinety-four older adults from 14 care homes wore an ActiGraph wGT3X+ accelerometer on the right hip for 7 consecutive days. A pragmatic, staged approach was adopted in order to explore the effect of: monitoring day; minimum daily wear time and number of wear days on estimates of four outcomes derived from the accelerometer data: counts.day− 1, counts.minute− 1, PA time and SB time.ResultsData from 91 participants (mean age: 84 ± 9 years, 34% male) was included in the analysis. No effect of monitoring day was observed. Lowering the daily wear time to ≥ 8 h (compared to ≥10 h) had no effect on the outcomes of interest. Four days of monitoring was sufficient to provide reliable estimates of all four outcomes.ConclusionIn this study, a minimum wear time criterion of ≥ 8 h on any 4 days was required to derive reliable estimates of PA and SB from ActiGraph wGT3X+ accelerometer data in older care home residents.

Sedentary Behavior in Childhood, Lower Arterial Compliance and Decreased Endothelial Function-Cross Sectional Data From a German School Cohort.

BackgroundEndothelial function by flow-mediated dilatation assesses early markers of atherosclerotic progression. Greater amounts of physical activity and physical fitness in children are associated with cardiovascular health benefits. We aimed to explore factors, influencing endothelial function and arterial compliance in a cohort of healthy school children.MethodsThe 94 participants (41 girls, 53 boys) in the study were young, healthy children from a German school cohort. Anthropometric data, body composition and blood pressure were assessed. Blood was drawn (8 h overnight fast), assessing total cholesterol, high density lipoprotein and low density lipoprotein and triglycerides. Endothelial function was diagnosed by flow-mediated dilatation with ultrasonography (ALOKA/Hitachi, Prosound alpha 6). Tracking gates were set on the intima in B-mode. The waveform of diameter changes over the cardiac cycle was displayed in real time using the FMD-mode of the eTRACKING system. Changes in arterial diameter at baseline, ischaemia and vasodilatation were measured. A symptom limited pulmonary exercise test on a bicycle ergometer was performed to test cardiorespiratory fitness. Physical activity was assessed using GT3x accelerometers (Actigraph, USA), over 4 days (including 1 week-end day), with a minimum wear-time duration of 10 h.ResultsThe median age was 12.2 years (11.8–12.8). Children were normal weight, blood lipid profiles (cholesterol, high-density lipoprotein, low-density lipoprotein, triglyceride) were in normal range. Baseline measurements during the diagnostics of endothelial function revealed higher arterial compliance of the brachial artery in boys. Boys' cardiorespiratory fitness was higher than compared to girls. Boys met the recommendations of 60 min moderate to vigorous activity, whereas girls were significantly less active and did not meet current recommendations. More time spent in sedentary activity was the main predictor for lower arterial compliance (adjusted for age and sex), accounting for 14% of the variance. No significant model revealed, analyzing the influencing factors such as anthropometric data, blood lipids, physical activity and fitness on endothelial function.ConclusionThis is the first study on endothelial function in association to objectively measured physical activity and cardiorespiratory fitness in healthy school children in Germany. The study highlights the importance of reducing time spent being sedentary to maintain endothelial health.

The Impact of Cumulative Cochlear Implant Wear Time on Spoken Language Outcomes at Age 3 Years.

Purpose The purpose of this study was to analyze the impact of cumulative hearing hour percentage (HHP) on pediatric cochlear implant users' speech and language development at age 3 years and to determine an evidence-based wear time recommendation that yields typical spoken language standard scores. Method A retrospective chart review of 40 pediatric cochlear implant recipients was completed. Children met the following criteria: prelingually deafened, implanted at age 2 years or younger, utilized a speech processor with datalogging capabilities, a minimum of 1 year of cochlear implant use, and language testing completed at approximately age 3 years. Exclusion criteria included significant inner ear malformation (i.e., common cavity) or developmental delay that would preclude spoken language development. Results Multiple regression analysis revealed that age and implantation and HHP were predictive of spoken language skills at age 3 years. Further analysis yielded wear time recommendations associated with age-appropriate spoken language based on the age at implantation. Conclusions When the goal is age-appropriate spoken language, wear time recommendations should reflect a child's current age, age at implantation, and the comparative daily sound access of age-matched normal-hearing peers. The HHP measurement can help provide that information. The minimum wear time recommendation should be set to 80% HHP with the ultimate goal of 100% HHP to give pediatric cochlear implant recipients enough access to sound and language to achieve their spoken language goals.

Determining Minimum Wear Time for Mobile Sensor Technology.

Part 1 in the DIA Study Endpoint Community Working Group on Mobile Sensor Technology (MST) series addresses considerations that may be useful when determining the minimum wear time associated with mobile sensor use to ensure reliable estimation of the clinical endpoint under consideration. What constitutes a minimum valid data set is a dilemma facing those using MSTs in clinical studies. If this alignment does not occur, the integrity of the data collected and conclusions drawn from these data may be in incorrect. While study participants should consent to engage with MSTs as defined in a protocol, participant behavior or technology lapses may result in capturing incomplete data. Drawing from the literature, we review what constitutes a minimum data set, the risks associated with missing data, alignment with the clinical endpoint(s) and goals of a study, as well as managing patient burden.

Stay in or play out? The influence of weather conditions on physical activity of grade 5 children in Canada.

Regular physical activity (PA) in children is essential for their development and prevention of overweight and obesity. Little is known about the effect of day-to-day variations in weather conditions on PA levels in school-aged children, particularly with regard to school compared to non-school days and girls compared to boys. Daily step count (7:00 a.m.-9:00 p.m.) from 972 grade 5 students aged 10-11years from 60 schools across Alberta, Canada, was collected using time-stamped pedometers (minimum wear time of two school and one non-school days) during March-June 2013. Time-matched weather conditions (actual and feels-like temperature, cloud coverage, and precipitation amount) were obtained from local weather stations in Alberta during the same period. Multilevel mixed-effect regression models were used to estimate the effect of each weather condition on daily step count. A 1°C increase in feels-like temperature was associated with 26 more steps/day (p < 0.05), while 1-unit increase in cloud coverage was associated with 61 fewer steps/day (p < 0.01). Compared to no precipitation, heavy precipitation (> 5mm/day) was associated with 1022 fewer steps/day (p < 0.01). Students' PA levels were associated with weather conditions more on non-school vs. school days and more among girls vs. boys. Results suggest that daily weather conditions can affect PA in school children, particularly outside school hours, and should be considered when evaluating PA levels or designing interventions to promote PA in children. Findings provide support for increased investment toward creating weather-appropriate physical activity opportunities for wet and colder days to prevent PA decline in children during inclement weather conditions.

Accelerometry to measure physical activity in toddlers: Determination of wear time requirements for a reliable estimate of physical activity

ABSTRACTAccelerometry is widely used to evaluate physical activity in toddlers however recommendations regarding wear time are needed to understand physical activity behaviours in this age group. This study aimed to determine the minimum wear time to reliably evaluate physical activity in toddlers. Children from the 3D Birth Cohort (n = 255, 49.8% boys, 2.1 ± 0.2 years) were asked to wear an accelerometer (GT3X+, ActiGraph) for 7 days. Physical activity was expressed in active time (min/day) and counts per minute (CPM). Single day intraclass correlation coefficients (ICCs) were calculated to assess the effect of varying minimal wear time on reliability estimates. The Spearman-Brown formula was used to determine wear time required to achieve reliability levels of 70%, 80% and 90%. For active time, a reliability of 72.1% was achieved with wearing the accelerometer for ≥ 4 days of ≥ 6 h, which comprised 85.9% of the sample. For CPM, ≥ 4 days of ≥ 6 h provided a reliability of 74.7% and comprised 85.9% of the children. Results differed slightly when girls and boys were analysed separately, but restricting analyses to children with a weekend day did not. In summary, a minimum of 4 days with ≥ 6 h of accelerometry data provides a reliable estimate of physical activity in 2-year toddlers.

Best practice guidelines for the measurement of physical activity levels in stroke survivors: a secondary analysis of an observational study.

The aim of this study was to investigate the phenomenon of activity (increased activity in response to monitor wear) and determine the minimum wear time of accelerometers when objectively measuring habitual physical activity levels of community dwelling stroke survivors. Exploratory, secondary analyses of cross-sectional data were carried out. Physical activity variables [sitting, standing and stepping time, step count, light physical activity and moderate-to-vigorous physical activity (MVPA)] were measured with two activity monitors for 7 days. Repeated-measures analysis of variance was used to assess reactivity. Minimum wear time was assessed using regression analyses and median absolute differences. Paired t-tests were used to assess differences between weekend and weekday activity levels. There was no evidence of reactivity. Minimum wear time was 3 days for all activity variables, with the exception of MVPA, for which 7 days of monitoring was required. There were no significant differences in weekend and weekday activity levels. To accurately measure activity levels of individuals with stroke, we recommend 3 days of monitoring for all activity variables, with the exception of MVPA, which requires 7 days.

Children's Compliance With Wrist-Worn Accelerometry Within a Cluster-Randomized Controlled Trial: Findings From the Healthy Lifestyles Programme.

The purpose of this study was to assess children's compliance with wrist-worn accelerometry during a randomized controlled trial and to examine whether compliance differed by allocated condition or gender. A total of 886 children within the Healthy Lifestyles Programme trial were randomly allocated to wear a GENEActiv accelerometer at baseline and 18-month follow-up. Compliance with minimum wear-time criteria (≥10h for 3 weekdays and 1 weekend day) was obtained for both time points. Chi-square tests were used to determine associations between compliance, group allocation, and gender. At baseline, 851 children had usable data, 830 (97.5%) met the minimum wear-time criteria, and 631 (74.1%) had data for 7days at 24hours per day. At follow-up, 789 children had usable data, 745 (94.4%) met the minimum wear-time criteria, and 528 (67%) had complete data. Compliance did not differ by gender (baseline: χ2 = 1.66, P = .2; follow-up: χ2 = 0.76, P = .4) or by group at follow-up (χ2 = 2.35, P = .13). The use of wrist-worn accelerometers and robust trial procedures resulted in high compliance at 2 time points regardless of group allocation, demonstrating the feasibility of using precise physical activity monitors to measure intervention effectiveness.

Accelerometer data requirements for reliable estimation of habitual physical activity and sedentary time of children during the early years - a worked example following a stepped approach

ABSTRACTThis study presents a worked example of a stepped process to reliably estimate the habitual physical activity and sedentary time of a sample of young children. A total of 299 children (2.9 ± 0.6 years) were recruited. Outcome variables were daily minutes of total physical activity, sedentary time, moderate to vigorous physical activity and proportional values of each variable. In total, 282 (94%) provided 3 h of accelerometer data on ≥1 day and were included in a 6-step process: Step-1: determine minimum wear-time; Step-2: process 7-day-data; Step-3: determine the inclusion of a weekend day; Step-4: examine day-to-day variability; Step-5: calculate single day intraclass correlation (ICC) (2,1); Step-6: calculate number of days required to reach reliability. Following the process the results were, Step-1: 6 h was estimated as minimum wear-time of a standard day. Step-2: 98 (32%) children had ≥6 h wear on 7 days. Step-3: no differences were found between weekdays and weekend days (P ≥ 0.05). Step-4: no differences were found between day-to-day variability (P ≥ 0.05). Step-5: single day ICC’s (2,1) ranged from 0.48 (total physical activity and sedentary time) to 0.53 (proportion of moderate to vigorous physical activity). Step-6: to reach reliability (ICC = 0.7), 3 days were required for all outcomes. In conclusion following a 7 day wear protocol, ≥6 h on any 3 days was found to have acceptable reliability. The stepped-process offers researchers a method to derive sample-specific wear-time criterion.

The feasibility and acceptability of questionnaires and accelerometry for measuring physical activity and sedentary behaviour in adults with mental illness

Background: Adults with mental illness may have difficulties with data collection methods such as questionnaires and accelerometry.Aims: To assess the utility of questionnaires and accelerometry for assessing physical activity (PA) and sedentary behaviour (SB) in non-institutionalised adults with mental illness.Methods: Participants were recruited from outpatient clinics and community organisations. Participants completed PA and SB questionnaires, wore accelerometers for 7 d, and rated the ease/difficulty of completing study components. Recruitment numbers, adherence, and ease/difficulty ratings were examined. Ease/difficulty ratings were compared between study components, and between participants by distress level.Results: One hundred forty-two participants completed the questionnaires; they found it easier to report PA than reclining time (p = 0.017), and reclining time than sitting time (p < 0.001). Participants with high distress found it more difficult to report sitting time and PA than participants with low distress (p < 0.017). Ninety-nine participants (70%) completed the accelerometry; the majority (88%) met the minimum wear-time criteria. They found it easier to wear the monitor during the day than while sleeping (p < 0.001), and easier to complete accelerometry than questionnaires (p < 0.001).Conclusions: Accelerometry was more feasible for assessing SB than questionnaires. Questionnaires were feasible for assessing PA, but less acceptable for people experiencing high distress.

Association of Body Composition and Physical Activity in Adolescents with Down Syndrome

Obesity is highly prevalent among persons with Down syndrome (DS). Low levels of moderate to vigorous physical activity (MVPA) likely contribute to this health disparity, but only low associative relationships have been found with body mass index (BMI). Due to characteristics of DS (e.g. short stature, unique fat distribution), BMI may not be precise enough to study this relationship. Three component analysis from dual-energy X-ray absportiometry (DXA) may assist with better understanding the association between body composition and MVPA. PURPOSE: To examine the association between total and regional fat mass from DXA and levels of MVPA from actigraphy. METHODS: Preliminary analyses were conducted with 6 adolescents (15±1.8yrs, 66% male) with DS who completed a DXA scan measuring total and regional (i.e. arms, legs, trunk) fat mass. BMI percentiles (CDC) from direct anthropometric measures were also calculated. Each participant wore a triaxial accelerometer for seven days at the waist. Puyau cut points, minimum wear time of 10 hours per day for 4 days, and 20 minute non-wear period criteria were used. Analyses include 1) descriptive statistics of DXA derived fat mass, BMI, and MVPA; and 2) bivariate correlations. RESULTS: Average percent body fat from DXA was 31% (±12%) with moderate to high body fatness detected in 66% of the sample. Average BMI was at the 89th (±11) percentile. Average MVPA was only 17.32 minutes per day. One participant met the guideline of 60 minutes of MVPA on a single day and 3 participants exceeded the 30 minute threshold on at least one day. The association between body fat and MVPA was stronger from DXA (r = −.794) than from BMI percentile (−.473). Among regional segments, associations were also high including the arms (−.871), legs (−.802), and trunk (−.782). Correlations did not reach significance (p<.05) due to sample size, but the r2 values are meaningful. CONCLUSION: Excess fatness and low MVPA are common in DS. This preliminary analysis found a stronger association between MVPA and body fat from DXA than from BMI. DXA may provide a more precise measure of excess body fat in DS. Greater use of DXA may help to better understand factors influencing body composition. A more comprehensive analysis will be possible with a larger sample and typically developing control group; currently in progress. Supported by NIH F31 HD079227.

Physical activity and fitness in women with metastatic breast cancer.

136 Background: Women with metastatic breast cancer may survive for many years after disease onset, and there is little published evidence on their habitual levels of physical activity. The aim of this study was to investigate differences in physical activity levels and physical fitness between women with and without metastatic breast cancer. Methods: Seventy-one women with metastatic breast cancer (METS) aged 57.7 ± 9.5 y and 2.9 ± 3.1 y after disease onset, and 71 healthy controls (CONTROLS) aged 55.0 ± 9.4 y participated. Of those with metastatic disease, 27% had metastases in bone only, 35% in viscera only and 38% in both bone and viscera. Strength was measured using hand and leg dynamometry, aerobic fitness using the Modified Canadian Aerobic Fitness Test, and fatigue with the FACT-Fatigue questionnaire. Participants wore a SenseWear physical activity armband over 6 days, and the average steps taken per day over 5 of these days, where there was a minimum wear time of 8 hours per day, was derived. Results: METS possessed lower aerobic fitness than CONTROLS (25.3 ± 5.4 versus 31.9 ± 6.1 ml·kg·min-1 respectively; p&lt;0.01). METS were significantly weaker than CONTROLS. Lower limb strength for the METS and CONTROLS was 53.8 ± 23.7 versus 76.0 ± 27.4 kg and handgrip strength was 26.6 ± 6.0 versus 30.2 ± 6.4 kg. METS were also significantly less active, attaining only 57% of the daily step counts of CONTROLS. Fatigue was significantly higher in women with metastatic cancer compared to their healthy counterparts (38.0 ± 9.8 versus 46.3 ± 4.6; p&lt;0.01). Correlation between fatigue with average steps per day (r=0.46), handgrip strength (r=0.29) and leg strength (r=0.26) was low in the METS group. Conclusions: Women living in the community with metastatic breast cancer are weaker, have lower aerobic fitness, and are relatively inactive compared to their healthy counterparts. Increased fatigue in these women is poorly associated with their decreased physical activity levels, hand and lower limb strength. Women with metastatic breast cancer may benefit from a program directed at improving their strength and fitness. Acknowledgements: Funded by National Breast Cancer Foundation, Australia.

Reliability of RT3 Accelerometers among Overweight and Obese Adults

Accurate and reliable measurement of physical activity plays an important role in assessing effective lifestyle interventions for obesity. This study examined reliability of accelerometer-based estimates of physical activity levels of overweight and obese adults before and after a lifestyle weight loss program. Participants were overweight and obese (body mass index = 25-45 kg x m) members (n = 1592; 67% female, 42% African American) of the multicenter weight loss maintenance trial. They wore RT3 accelerometers during waking hours for 7 d at baseline and after a 6-month weight loss intervention that included diet and physical activity recommendations. Moderate-to-vigorous physical activity (MVPA) and MVPA occurring in bouts >or=10 min (bout MVPA) were assessed. At baseline, wear time minimums of 10 and 6 h.d resulted in similar average minutes per day of MVPA (18.3 and 18.0 min) and MVPA bout minutes per day (6.9 and 6.7 min). Similar wear times occurred after the weight loss intervention for MVPA (27.0 and 26.8 min) and bout MVPA (15.1 and 15.0 min). Reliability measurements by intraclass correlation (ICC) were larger for 4 versus 2 d x wk minimum wear time for both MVPA and bout MVPA (4-d ICC = 0.27-0.44 and 2-d ICC = 0.19-0.38), but there was little increase in ICC comparing 4 (ICC = 0.27-0.44) and 7 d x wk (ICC = 0.30-0.46). Longer wear time requirements did not result in significant increases in reliability. Using 4 d of data with >or=6 h x d of wear time optimized the balance between ICC and participant burden in overweight and obese adults before and after a weight loss intervention. Future investigations using accelerometers to estimate MVPA in overweight and obese samples can consider requiring less monitor wear time.