Commercially available activity monitors such as the fitbit charge and apple watch show poor validity in patients with gait aids after total knee arthroplasty.

PURPOSE: The aim of this study is to determine the validity of consumer grade step counter devices during the early recovery period after knee replacement surgery. METHODS: Twenty-three participants wore a Fitbit Charge or Apple Watch Series 4 smart watch and performed a walking test along a 50-metre hallway. There were 9 males and 14 females included in the study with an average age of 68.5 years and BMI of 32. Each patient wore both the Fitbit Charge and Apple Watch while completing the walking test and an observer counted the ground truth value using a thumb-push tally counter. This test was repeated pre-operatively with no gait aid, immediately post operatively with a walker, at 6 weeks follow up with a cane and at 6 months with no gait aid. Bland-Altman plots were performed for all walking tests to compare the agreement between measurement techniques. RESULTS: Mean overall agreement of step count for pre-operative and at 6 months for subjects walking without gait aids was excellent for both the Apple Watch vs. actual and Fitbit vs. actual with bias values ranging from - 0.87 to 1.36 with limits of agreement (LOA) ranging between - 10.82 and 15.91. While using a walker both devices showed extremely little agreement with the actual step count with bias values between 22.5 and 24.37 with LOA between 11.7 and 33.3. At 6 weeks post-op while using a cane, both the Apple Watch and Fitbit devices had a range of bias values between - 2.8 and 5.73 with LOA between - 13.51 and 24.97. CONCLUSIONS: These devices show poor validity in the early post operative setting, especially with the use of gait aids, and therefore results should be interpreted with caution.

Postoperative Complications and Mobilization Following Major Abdominal Surgery With Versus Without Fitness Tracker-based Feedback (EXPELLIARMUS): A Student-led Multicenter Randomized Controlled Clinical Trial of the CHIR-Net SIGMA Study Group.

OBJECTIVE: To determine whether daily postoperative step goals and feedback through a fitness tracker (FT) reduce the rate of postoperative complications after surgery. BACKGROUND: Early and enhanced postoperative mobilization has been advocated to reduce postoperative complications, but it is unknown whether FT alone can reduce morbidity. METHODS: EXPELLIARMUS was performed at 11 University Hospitals across Germany by the student-led clinical trial network SIGMA. Patients undergoing major abdominal surgery were enrolled, equipped with an FT, and randomly assigned to the experimental (visible screen) or control intervention (blackened screen). The experimental group received daily step goals and feedback through the FT. The primary end point was postoperative morbidity within 30 days using the Comprehensive Complication Index (CCI). All trial visits were performed by medical students in the hospital with the opportunity to consult a surgeon-facilitator who also obtained informed consent. After discharge, medical students performed the 30-day postoperative visit through telephone and electronic questionnaires. RESULTS: A total of 347 patients were enrolled. Baseline characteristics were comparable between the 2 groups. The mean age of patients was 58 years, and 71% underwent surgery for malignant disease, with the most frequent indications being pancreatic, colorectal, and hepatobiliary malignancies. Roughly one-third of patients underwent laparoscopic surgery. No imputation for the primary end point was necessary as data completeness was 100%. There was no significant difference in the CCI between the 2 groups in the intention-to-treat analysis (mean±SD CCI experimental group: 23±24 vs. control: 22±22; 95% CI: -6.1, 3.7; P=0.628). All secondary outcomes, including quality of recovery, 6-minute walking test, length of hospital stay, and step count until postoperative day 7 were comparable between the 2 groups. CONCLUSIONS: Daily step goals combined with FT-based feedback had no effect on postoperative morbidity. The EXPELLIARMUS shows that medical students can successfully conduct randomized controlled trials in surgery.

Accuracy of consumer-based activity trackers to measure and coach patients with lower limb lymphoedema.

PURPOSE: This study investigated the accuracy of activity trackers in chronic lower limb lymphoedema (LLL) patients and in comparison to matched controls. MATERIALS AND METHODS: Seventeen LLL patients and 35 healthy subjects wore an activity tracker at the hip (Fitbit Zip/Inspire; hip-AT) and one at the wrist (Fitbit Alta/Inspire; wrist-AT) combined with a reference activity monitor (Dynaport Movemonitor; DAM), for 14 consecutive days. To analyze accuracy and agreement, mean daily step count from both AT's were compared to DAM. To evaluate the accuracy as coaching tool, day-by-day differences were calculated. The Kendall correlation coefficient was used to test consistency of ranking daily steps between the AT's and the DAM. RESULTS: The wrist-AT significantly overestimated daily step count compared to DAM in the LLL group (+1221 ± 1754 steps per day, p = 0.011) while the hip-AT underestimated the step count, although not significantly. Similar results were found in the healthy control group. As a coaching tool, both wrist-AT and hip-AT showed a moderate correlation with the DAM (r = 0.507 and 0.622, respectively) in the LLL group regarding consistency of ranking from most to least active days. CONCLUSION: Wrist-AT's significantly overestimate daily step count in a LLL population. As a coaching tool, both trackers show moderate validity, indicating applicability to improve physical activity.

Deconstructing Fitbit to Specify the Effective Features in Promoting Physical Activity Among Inactive Adults: Pilot Randomized Controlled Trial.

BACKGROUND: Wearable activity trackers have become key players in mobile health practice as they offer various behavior change techniques (BCTs) to help improve physical activity (PA). Typically, multiple BCTs are implemented simultaneously in a device, making it difficult to identify which BCTs specifically improve PA. OBJECTIVE: We investigated the effects of BCTs implemented on a smartwatch, the Fitbit, to determine how each technique promoted PA. METHODS: This study was a single-blind, pilot randomized controlled trial, in which 70 adults (n=44, 63% women; mean age 40.5, SD 12.56 years; closed user group) were allocated to 1 of 3 BCT conditions: self-monitoring (feedback on participants' own steps), goal setting (providing daily step goals), and social comparison (displaying daily steps achieved by peers). Each intervention lasted for 4 weeks (fully automated), during which participants wore a Fitbit and responded to day-to-day questionnaires regarding motivation. At pre- and postintervention time points (in-person sessions), levels and readiness for PA as well as different aspects of motivation were assessed. RESULTS: Participants showed excellent adherence (mean valid-wear time of Fitbit=26.43/28 days, 94%), and no dropout was recorded. No significant changes were found in self-reported total PA (dz<0.28, P=.40 for the self-monitoring group, P=.58 for the goal setting group, and P=.19 for the social comparison group). Fitbit-assessed step count during the intervention period was slightly higher in the goal setting and social comparison groups than in the self-monitoring group, although the effects did not reach statistical significance (P=.052 and P=.06). However, more than half (27/46, 59%) of the participants in the precontemplation stage reported progress to a higher stage across the 3 conditions. Additionally, significant increases were detected for several aspects of motivation (ie, integrated and external regulation), and significant group differences were identified for the day-to-day changes in external regulation; that is, the self-monitoring group showed a significantly larger increase in the sense of pressure and tension (as part of external regulation) than the goal setting group (P=.04). CONCLUSIONS: Fitbit-implemented BCTs promote readiness and motivation for PA, although their effects on PA levels are marginal. The BCT-specific effects were unclear, but preliminary evidence showed that self-monitoring alone may be perceived demanding. Combining self-monitoring with another BCT (or goal setting, at least) may be important for enhancing continuous engagement in PA. TRIAL REGISTRATION: Open Science Framework; https://osf.io/87qnb/?view_only=f7b72d48bb5044eca4b8ce729f6b403b.

A Review of the Validity and Reliability of Accelerometer-Based Metrics From Upper Back-Mounted GNSS Player Tracking Systems for Athlete Training Load Monitoring.

ABSTRACT: Dawson, L, Beato, M, Devereux, G, and McErlain-Naylor, SA. A review of the validity and reliability of accelerometer-based metrics from upper back-mounted GNSS player tracking systems for athlete training load monitoring. J Strength Cond Res 38(8): e459-e474, 2024-Athlete load monitoring using upper back-mounted global navigation satellite system (GNSS) player tracking is common within many team sports. However, accelerometer-based load monitoring may provide information that cannot be achieved with GNSS alone. This review focuses on the accelerometer-based metrics quantifying the accumulation of accelerations as an estimation of athlete training load, appraising the validity and reliability of accelerometer use in upper back-mounted GNSS player tracking systems, the accelerometer-based metrics, and their potential for application within athlete monitoring. Reliability of GNSS-housed accelerometers and accelerometer-based metrics are dependent on the equipment model, signal processing methods, and the activity being monitored. Furthermore, GNSS unit placement on the upper back may be suboptimal for accelerometer-based estimation of mechanical load. Because there are currently no feasible gold standard comparisons for field-based whole-body biomechanical load, the validity of accelerometer-based load metrics has largely been considered in relation to other measures of training load and exercise intensity. In terms of convergent validity, accelerometer-based metrics (e.g., PlayerLoad, Dynamic Stress Load, Body Load) have correlated, albeit with varying magnitudes and certainty, with measures of internal physiological load, exercise intensity, total distance, collisions and impacts, fatigue, and injury risk and incidence. Currently, comparisons of these metrics should not be made between athletes because of mass or technique differences or between manufacturers because of processing variations. Notable areas for further study include the associations between accelerometer-based metrics and other parts of biomechanical load-adaptation pathways of interest, such as internal biomechanical loads or methods of manipulating these metrics through effective training design.

Physical Activity, Body Composition, and Fitness Variables in Adolescents After Periods of Mandatory, Promoted or Nonmandatory, Nonpromoted Use of Step Tracker Mobile Apps: Randomized Controlled Trial.

BACKGROUND: It is not known whether an intervention made mandatory as a physical education (PE) class assignment and aimed at promoting physical activity (PA) in adolescents can create a healthy walking habit, which would allow further improvements to be achieved after the mandatory and promoted intervention has been completed. OBJECTIVE: The aims of this study were to (1) investigate whether, after a period of using a step tracker mobile app made mandatory and promoted as a PE class assignment, adolescents continue to use it when its use is no longer mandatory and promoted; (2) determine whether there are changes in the PA level, body composition, and fitness of adolescents when the use of the app is mandatory and promoted and when it is neither mandatory nor promoted; and (3) analyze whether the covariates maturity status, gender, and specific app used can have an influence. METHODS: A total of 357 students in compulsory secondary education (age: mean 13.92, SD 1.91 y) participated in the study. A randomized controlled trial was conducted consisting of 2 consecutive 10-week interventions. Participants' PA level, body composition, and fitness were measured at baseline (T1), after 10 weeks of mandatory and promoted app use (T2), and after 10 weeks of nonmandatory and nonpromoted app use (T3). Each participant in the experimental group (EG) used 1 of 4 selected step tracker mobile apps after school hours. RESULTS: The results showed that when the use of the apps was neither mandatory nor promoted as a PE class assignment, only a few adolescents (18/216, 8.3%) continued the walking practice. After the mandatory and promoted intervention period (T1 vs T2), a decrease in the sum of 3 skinfolds (mean difference [MD] 1.679; P=.02) as well as improvements in the PA level (MD -0.170; P<.001), maximal oxygen uptake (MD -1.006; P<.001), countermovement jump test (MD -1.337; P=.04), curl-up test (MD -3.791; P<.001), and push-up test (MD -1.920; P<.001) in the EG were recorded. However, the changes between T1 and T2 were significantly greater in the EG than in the control group only in the PA level and curl-up test. Thus, when comparing the measurements taken between T1 and T3, no significant changes in body composition (P=.07) or fitness (P=.84) were observed between the EG and the control group. The covariates maturity status, gender, and specific app used showed a significant effect in most of the analyses performed. CONCLUSIONS: A period of mandatory and promoted use of step tracker mobile apps benefited the variables of body composition and fitness in adolescents but did not create a healthy walking habit in this population; therefore, when the use of these apps ceased to be mandatory and promoted, the effects obtained disappeared. TRIAL REGISTRATION: ClinicalTrials.gov NCT06164041; https://clinicaltrials.gov/study/NCT06164041.

Exploring Health-Related Quality of Life in Children With Hypertrophic Cardiomyopathy and Relationship to Physical Activity.

BACKGROUND: Hypertrophic cardiomyopathy is a burdensome condition that inflicts both physical and psychological impairment on those with the disease, negatively impacting health-related quality of life (HRQoL). Given the abundance of evidence suggesting a role of physical activity (PA) in modulating HRQoL in healthy populations of children, we sought to determine the relationship between HRQoL and PA in children diagnosed with hypertrophic cardiomyopathy. METHODS AND RESULTS: A multicenter prospective observational cohort study was conducted, with patients with hypertrophic cardiomyopathy aged 10 to 19 years being provided a wrist-worn activity tracker (Fitbit Charge HR) to wear for 14 days. Patients self-reported on Pediatric Quality of Life 4.0 quality of life inventory items, which were associated with PA metrics following covariate adjustment using linear regression. A total of 56 participants were recruited to the study. The median age at enrollment was 15.5 years (interquartile range, 13.8-16.8), and 16 out of 56 (29%) of the cohort were girls. The cohort reported decreased metrics of physical, psychosocial, and total summary scores compared with health reference populations, with scores comparable with that of published populations with chronic disease. Increased physical HRQoL scores were significantly associated with increased daily steps taken, distance traveled, and flights of stairs climbed. CONCLUSIONS: These results show that impaired PA correlates with reduced HRQoL in children with hypertrophic cardiomyopathy, suggesting PA may partially mediate HRQoL in this population.

Continuous Assessment of Active-Duty Army Special Operations and Reconnaissance Marines Using Digital Devices and Custom Software: The Digital Comprehensive Operator Readiness Assessment (DcORA) Study.

BACKGROUND: Continuous exposure to extreme and chronic stress from uncontrollable events has been linked to increased psychological and physiological reactivity. Prolonged, frequent deployments may test coping skills over time, ultimately rendering Servicemembers vulnerable to mental health problems and suicide. This study develops a methodology for accurately collecting holistic health measures from Servicemembers using digital tools, including custom-built phone software and body-worn sensors. METHODS: The secure research platform and mobile app continuously collect multiple health measures and, after data analysis, deliver continuously updated summary data back to the Servicemember. This system provides novel insights into the relationships between the measures while helping individuals track their progress toward self-established goals. Participants were given an iPhone (including the study app) and an Apple Watch. Participants tracked their data for more than 6 months and responded to baseline, daily, and weekly questions and assessments. Physiologic, psychologic, and cognitive assessment data across the Preservation of the Force and Family program (POTFF) domains were collected, displayed to the individual, and analyzed in aggregate. RESULTS: When coupled with custom-built software, this hardware can be elevated from a fitness tracker to a user-facing health monitoring, educational, and delivery system. CONCLUSION: This wearable system measured vital factors associated with the health and human performance of Servicemembers. In real-time, it engaged Servicemembers in health and human performance optimization practices to achieve a goal of prevention of physical or mental injury.

The use of wearable devices on physical activity levels among individuals living with diabetes: 2017 BRFSS.

AIM: This study aims to examine the association between wearing wearable devices and physical activity levels among people living with diabetes. METHODS: 1298 wearable device users and nonusers living with diabetes from eight states of the 2017 Behavioral Risk Factors Surveillance System were included in the analysis. Unadjusted and adjusted linear regression was performed to determine the association between self-reported physical activity per week (min) and wearable device usage (users and nonusers) among people living with diabetes using survey analysis. RESULTS: 84.97 % (95 % CI [80.39, 88.89]) of participants were nonusers of wearable devices, while 15.03 % (95 % CI [11.11, 19.61]) were users. Across the sample, the average weekly physical activity was 427.39 mins (95 % Cl [356.43, 498.35]). Nonusers had a higher physical activity per week with 433.83 mins (95 % CI [353.59, 514.07]), while users only had 392.59 mins (95 % CI [253.48, 531.69]) of physical activity per week. However, the differences between the two groups were non-statistically significant (p=.61). In both adjusted and unadjusted linear regressions between physical activity per week and wearable device usage, statistically significant associations were not found (unadjusted: ß=-41.24, p=.62; adjusted: ß=-56.41, p=.59). CONCLUSION: Further research is needed to determine the effectiveness of wearable devices in promoting physical activity among people with diabetes. Additionally, there is a need to determine how people with diabetes use wearable devices that could promote physical activity levels.

Changes in sedentary behavior in the chronic phase following stroke.

BACKGROUND: Sedentary behavior increases risk for cardiovascular diseases. Little is known about sedentary behavior through the chronic phase after stroke. We aimed to describe how long and short bouts of sedentary behavior changed over the first three years after stroke and if cognition at baseline was an independent risk factor for sedentary behavior. METHODS: This is a sub-study of the Norwegian cognitive impairment after stroke (Nor-COAST) study, a multicenter study recruiting patients with acute stroke. Sedentary behavior was monitored with a thigh-worn sensor (ActivPal3®), at three-, 18- and 36-months post stroke. Stroke severity was assessed by National Institutes of Health Stroke Scale (NIHSS) and cognition by Montreal cognitive assessment (MoCA). Mixed model analysis with mean number of sedentary minutes accumulated daily as the dependent variable was repeated for all four zones (<30min, 30-60min, 60-90min, >90min) and for total sedentary time. RESULTS: The number of included participants was 528 (mean age 71.4, NIHSS on day 1, 2.7). The total amount of sedentary time accumulated between 08.00-22.00 increased significantly from about 9.8 hours at three months to 10.1 hours at 36 months post stroke (p=0.002). Patient characteristics associated with prolonged duration of the sedentary bouts and sedentary time were age, high BMI, comorbidities, and impaired physical function. No significant associations between MoCA score and sedentary time were found. CONCLUSION: The participants became increasingly sedentary and had fewer breaks in sedentary time from three to 36 months after stroke. Baseline cognition was not related to later sedentary behavior.

Text Messages to Promote Physical Activity in Patients With Cardiovascular Disease: A Micro-Randomized Trial of a Just-In-Time Adaptive Intervention.

BACKGROUND: Text messages may enhance physical activity levels in patients with cardiovascular disease, including those enrolled in cardiac rehabilitation. However, the independent and long-term effects of text messages remain uncertain. METHODS: The VALENTINE study (Virtual Application-supported Environment to Increase Exercise) was a micro-randomized trial that delivered text messages through a smartwatch (Apple Watch or Fitbit Versa) to participants initiating cardiac rehabilitation. Participants were randomized 4× per day over 6-months to receive no text message or a message encouraging low-level physical activity. Text messages were tailored on contextual factors (eg, weather). Our primary outcome was step count 60 minutes following a text message, and we used a centered and weighted least squares mean method to estimate causal effects. Given potential measurement differences between devices determined a priori, data were assessed separately for Apple Watch and Fitbit Versa users over 3 time periods corresponding to the initiation (0-30 days), maintenance (31-120 days), and completion (121-182 days) of cardiac rehabilitation. RESULTS: One hundred eight participants were included with 70 552 randomizations over 6 months; mean age was 59.5 (SD, 10.7) years with 36 (32.4%) female and 68 (63.0%) Apple Watch participants. For Apple Watch participants, text messages led to a trend in increased step count by 10% in the 60-minutes following a message during days 1 to 30 (95% CI, -1% to +20%), with no effect from days 31 to 120 (+1% [95% CI, -4% to +5%]), and a significant 6% increase during days 121 to 182 (95% CI, +0% to +11%). For Fitbit users, text messages significantly increased step count by 17% (95% CI, +7% to +28%) in the 60-minutes following a message in the first 30 days of the study with no effect subsequently. CONCLUSIONS: In patients undergoing cardiac rehabilitation, contextually tailored text messages may increase physical activity, but this effect varies over time and by device. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04587882.

Exactitud del Xiaomi Mi Band 4 para contabilizar pasos en adultos con enfermedades respiratorias crónicas. Estudio de concordancia / Accuracy of the Xiaomi Mi Band 4 for Steps Counting in Adults with Chronic Respiratory Diseases. Agreement Study

Introducción: El Xiaomi Mi Band 4 (XMB4) demostró ser exacto para medir pasos en sujetos sanos, pero no ha sido estudiado en pacientes con enfermedades respiratorias crónicas (ERC). Objetivos: Evaluar la exactitud del XMB4 para cuantificar pasos caminados en pacientes con ERC. Secundariamente, evaluar su viabilidad y usabilidad.Material y métodos: Estudio de concordancia contrastando los datos del XMB4 con la video-filmación (prueba de referencia). Fueron incluidos mayores de 18 años con diversas ERC y excluidos aquellos con deterioro cognitivo, limitaciones osteoarticulares y/o cardiovasculares que impedían la marcha. Realizamos un muestreo por conveniencia de pacientes que participaban de un programa de rehabilitación pulmonar.Las variables estudiadas incluyeron número de pasos, distancia y tiempo caminado, velocidad de la marcha, viabilidad y usabilidad. Cada participante realizó cinco caminatas (5, 10 y 30 metros, y 5 minutos a ritmo lento y rápido). Para testear la equivalencia estadística, necesitamos incluir 33 pacientes y utilizamos el método de intervalo de confianza con una zona de equivalencia de ±15%. Resultados: Fueron incluidos 33 pacientes, 64% mujeres, con una mediana (P25-75) de edad de 64,9 (55,8 a 70,2) años. Los pasos registrados por el XMB4 fueron equivalentes a los de la video-filmación en las diferentes caminatas, excepto en la de 5 metros. Los pasos fueron subestimados con un error de medición menor al 15%. Conclusiones: El XMB4 tiene una exactitud aceptable para medir pasos en pacientes con ERC excepto en caminatas muy cortas, es viable y fácil de usar

Introduction: Xiaomi Mi Band 4 (XMB4) has been shown to be accurate to measure steps in healthy subjects, but has not been studied in patients with chronic respiratory diseases (CRD).Objectives: To evaluate the accuracy of the XMB4 to quantify steps walked in patients with CRD. Secondarily, evaluate its feasibility and usability.Materials and methods: Agreement study compared the XMB4 data with the video (reference test). Adults aged 18 years or older with various CRD were included and those with cognitive impairment, osteoarticular and/or cardiovascular limitations that prevented walking were excluded. We conducted a convenience sampling of patients participating in a pulmonary rehabilitation program. Outcome measures studied included number of steps, distance and time walked, walking speed, feasibility and usability. Each participant performed five walks (5, 10 and 30 meters, and 5 minutes at a slow and fast pace).To test statistical equivalence we need to include 33 patients and use the confidence interval method with an equivalence zone of ±15%.Results: 33 patients were included, 64% women, with a median (P25-75) age of 64.9 (55.8 to 70.2) years. The steps recorded by the XMB4 were equivalent to those of the video in the different walks, except for the 5-meter walk. The steps were underestimated with a measurement error of less than 15%.Conclusions: XMB4 has acceptable accuracy for measuring steps in patients with CRD except for very short walks, it is feasible and easy to us.

Applications of wearable activity monitors for prostate cancer survivors: A systematic scoping review.

BACKGROUND: Wearable technology is used to monitor and motivate physical activity (PA) and provides continuous, objective PA and sleep data outside the clinical setting. We reviewed the literature to understand how wearables are integrated into prostate cancer (PC) investigations in order to identify current practices, gaps, and research opportunities. METHODS: We conducted a literature search for articles using wearables, among PC survivors published between 2012 and 2022. We extracted study details, interventions and outcomes, participant baseline characteristics, and device characteristics and grouped them by study type: randomized control trials (RCTs) and non-randomized studies. RESULTS: Of 354 articles screened, 44 met eligibility criteria (23 RCTs, and 21 non-randomized). 89% used wearables to monitor PA metrics, 11%, sleep metrics, and 6.8%, both. Most studies involved exercise (70% RCTs, 9% non-randomized studies) or lifestyle interventions (30% RCTs, 9% non-randomized studies). Intervention delivery methods included personalized computer-based (48%), in-person (e.g., trainer) (20%), and education web or print-based (20%). Interventions occurred at the participant's home (48%) or at a gym (20%). 57% of the studies evaluated the feasibility and acceptability of the wearable as an activity-measuring device or as part of a remotely delivered computer-based intervention. Studies used wearables to monitor adherence to PA interventions, motivate behavior change, to assess patient outcomes (e.g., patient function, quality of life, mood), or as data collection tools. CONCLUSIONS: Wearables are primarily being used to assess daily activity and monitor adherence to exercise interventions in clinical studies involving PC survivors. Findings suggest that they are feasible for use in this population. More research is needed to understand how to integrate wearables into routine clinical care, expand their use to predict clinical outcomes, or to deliver tailored interventions for PC survivors.

An Adaptive Behavioral Intervention for Weight Loss Management: A Randomized Clinical Trial.

Importance: Lifestyle interventions for weight loss are difficult to implement in clinical practice. Self-managed mobile health implementations without or with added support after unsuccessful weight loss attempts could offer effective population-level obesity management. Objective: To test whether a wireless feedback system (WFS) yields noninferior weight loss vs WFS plus telephone coaching and whether participants who do not respond to initial treatment achieve greater weight loss with more vs less vigorous step-up interventions. Design, Setting, and Participants: In this noninferiority randomized trial, 400 adults aged 18 to 60 years with a body mass index of 27 to 45 were randomized in a 1:1 ratio to undergo 3 months of treatment initially with WFS or WFS plus coaching at a US academic medical center between June 2017 and March 2021. Participants attaining suboptimal weight loss were rerandomized to undergo modest or vigorous step-up intervention. Interventions: The WFS included a Wi-Fi activity tracker and scale transmitting data to a smartphone app to provide daily feedback on progress in lifestyle change and weight loss, and WFS plus coaching added 12 weekly 10- to 15-minute supportive coaching calls delivered by bachelor's degree-level health promotionists viewing participants' self-monitoring data on a dashboard; step-up interventions included supportive messaging via mobile device screen notifications (app-based screen alerts) without or with coaching or powdered meal replacement. Participants and staff were unblinded and outcome assessors were blinded to treatment randomization. Main Outcomes and Measures: The primary outcome was the between-group difference in 6-month weight change, with the noninferiority margin defined as a difference in weight change of -2.5 kg; secondary outcomes included between-group differences for all participants in weight change at 3 and 12 months and between-group 6-month weight change difference among nonresponders exposed to modest vs vigorous step-up interventions. Results: Among 400 participants (mean [SD] age, 40.5 [11.2] years; 305 [76.3%] women; 81 participants were Black and 266 were White; mean [SD] body mass index, 34.4 [4.3]) randomized to undergo WFS (n = 199) vs WFS plus coaching (n = 201), outcome data were available for 342 participants (85.5%) at 6 months. Six-month weight loss was -2.8 kg (95% CI, -3.5 to -2.0) for the WFS group and -4.8 kg (95% CI, -5.5 to -4.1) for participants in the WFS plus coaching group (difference in weight change, -2.0 kg [90% CI, -2.9 to -1.1]; P < .001); the 90% CI included the noninferiority margin of -2.5 kg. Weight change differences were comparable at 3 and 12 months and, among nonresponders, at 6 months, with no difference by step-up therapy. Conclusions and Relevance: A wireless feedback system (Wi-Fi activity tracker and scale with smartphone app to provide daily feedback) was not noninferior to the same system with added coaching. Continued efforts are needed to identify strategies for weight loss management and to accurately select interventions for different individuals to achieve weight loss goals. Trial Registration: ClinicalTrials.gov Identifier: NCT02997943.

Home-based Circuit Training and Community Walking for Intermittent Claudication.

BACKGROUND: Supervised exercise training is recommended for people with peripheral artery disease (PAD), yet it remains underutilized. Home-based exercise programs (HBEPs) are a potential alternative. The aim of this study was to assess the feasibility of conducting a full scale trial of a 12-week HBEP for people living with symptomatic PAD. METHODS: In a randomized feasibility trial, patients with intermittent claudication were allocated to either an HBEP or a nonexercise control. The HBEP group was given a Fitbit to use during a 12-week exercise program comprising of personalized step goals and a resistance-based circuit to be undertaken at home twice weekly. The primary outcome was feasibility, assessed via eligibility, recruitment, attrition, tolerability, and adherence. Acceptability was assessed via semistructured interviews. Secondary analysis was undertaken to determine the feasibility of collecting clinical outcome data. RESULTS: 188 people were screened, 133 were eligible (70.7%), 30 were recruited (22.6%) and one withdrew (3.33%). Mean adherence to the daily step goal was 53.5% (range = 29.8-90.5%), and 58.6% of prescribed circuits were completed of which 56.4% were at the desired intensity. Six adverse events were recorded, 3 of which were related to study involvement. No significant differences were observed in exploratory outcomes. Small clinically important differences were seen in walking speed and pain-free treadmill walking distance which should be confirmed or refuted in a larger trial. CONCLUSIONS: The HBEP was feasible and well tolerated, with successful recruitment and minimal attrition. The intervention was acceptable, with walking seen as more enjoyable than circuit exercise. The WALKSTRONG program may be suitable for those who will not, or cannot, take part in supervised exercise outside of the home.

Performance of wearable sleep trackers during nocturnal sleep and periods of simulated real-world smartphone use.

GOAL AND AIMS: To test sleep/wake transition detection of consumer sleep trackers and research-grade actigraphy during nocturnal sleep and simulated peri-sleep behavior involving minimal movement. FOCUS TECHNOLOGY: Oura Ring Gen 3, Fitbit Sense, AXTRO Fit 3, Xiaomi Mi Band 7, and ActiGraph GT9X. REFERENCE TECHNOLOGY: Polysomnography. SAMPLE: Sixty-three participants (36 female) aged 20-68. DESIGN: Participants engaged in common peri-sleep behavior (reading news articles, watching videos, and exchanging texts) on a smartphone before and after the sleep period. They were woken up during the night to complete a short questionnaire to simulate responding to an incoming message. CORE ANALYTICS: Detection and timing accuracy for the sleep onset times and wake times. ADDITIONAL ANALYTICS AND EXPLORATORY ANALYSES: Discrepancy analysis both including and excluding the peri-sleep activity periods. Epoch-by-epoch analysis of rate and extent of wake misclassification during peri-sleep activity periods. CORE OUTCOMES: Oura and Fitbit were more accurate at detecting sleep/wake transitions than the actigraph and the lower-priced consumer sleep tracker devices. Detection accuracy was less reliable in participants with lower sleep efficiency. IMPORTANT ADDITIONAL OUTCOMES: With inclusion of peri-sleep periods, specificity and Kappa improved significantly for Oura and Fitbit, but not ActiGraph. All devices misclassified motionless wake as sleep to some extent, but this was less prevalent for Oura and Fitbit. CORE CONCLUSIONS: Performance of Oura and Fitbit is robust on nights with suboptimal bedtime routines or minor sleep disturbances. Reduced performance on nights with low sleep efficiency bolsters concerns that these devices are less accurate for fragmented or disturbed sleep.

Device-measured physical activity and sedentary time in the Nordic countries: A scoping review of population-based studies.

PURPOSE: The purpose of this scoping review was to summarize and describe the methodology and results from population-based studies of physical activity and sedentary time measured with devices in the Nordic countries (Denmark, Finland, Iceland, Norway, and Sweden) and published in 2000 or later. METHODS: A systematic search was carried out in PubMed and Web of Science in June 2023 using predefined search terms. RESULTS: Fourteen unique research projects or surveillance studies were identified. Additionally, 2 surveillance studies published by national agencies were included, resulting in a total of 16 studies for inclusion. National surveillance systems exist in Finland and Norway, with regular survey waves in school-aged children/adolescents and adults. In Denmark, recent nationally representative data have been collected in school children only. So far, Sweden has no regular national surveillance system using device-based data collection. No studies were found from Iceland. The first study was conducted in 2001 and the most recent in 2022, with most data collected from 2016 to date. Five studies included children/adolescents 6-18 years, no study included preschoolers. In total 11 studies included adults, of which 8 also covered older adults. No study focused specifically on older adults. The analytical sample size ranged from 205 to 27,890. Detailed methodology is presented, such as information on sampling strategy, device type and placement, wear protocols, and physical activity classification schemes. Levels of physical activity and sedentary time in children/adolescents, adults, and older adults across the Nordic countries are presented. CONCLUSION: A growing implementation of device-based population surveillance of physical activity and sedentary behavior in the Nordic countries has been identified. The variety of devices, placement, and data procedures both within and between the Nordic countries highlights the challenges when it comes to comparing study outcomes as well as the need for more standardized data collection.

Patient-perceived factors influencing physical activity sensor use in stroke prevention and rehabilitation: A thematic synthesis protocol.

INTRODUCTION: While the putative benefits of "fitness trackers" continue to fuel a booming consumer market, results of device-based clinical interventions remain remarkably mixed. This study will explore factors influencing wearable physical activity (PA) sensor use in the context of stroke prevention and rehabilitation for older adults. The findings of this thematic synthesis will provide insights into factors influencing the use of PA sensors in stroke which may inform more effective device-based interventions. METHODS AND ANALYSIS: Thematic synthesis as a formal method described by Thomas and Arden can be used within a systematic review to synthesize primary qualitative research. Accordingly, the proposed study will systematically search bibliographic databases for relevant peer-reviewed papers and synthesize coded thematic data within included papers. The quality of papers will be assessed using the JBI Critical Appraisal Checklist for Qualitative Research. Patterns in the text will be coded, preliminary data visualised, and higher-level analytical themes discerned to explain factors influencing the use of PA sensors in older stroke patients. DISCUSSION: This study does not require ethics approval. Results are expected to be available by June 2024. Data from the thematic synthesis will provide insights into barriers and facilitators influencing the use of wearable PA sensors in stroke and older adults at risk, and implications these factors have for the design of effective device-based interventions. TRIAL REGISTRATION: Systematic review registration: PROSPERO registration number: CRD42020211472. https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020211472.

Use of activity trackers to improve blood pressure in young people at risk for cardiovascular disease: a pilot randomized controlled trial.

BACKGROUND: Promoting physical activity among young individuals with cardiovascular disease (CVD) risk factors such as hypertension, diabetes, or chronic kidney disease can lower systolic blood pressure (BP). We sought to determine whether a 6-month intervention using a physical activity tracker was feasible and effective, compared with usual care. METHODS: Participants were recruited at a single academic medical center. Those aged 8-30 years were randomized in a 2:1 ratio to either the intervention (use of a Fitbit physical activity tracker coupled with feedback regarding the participant's step count) or usual care. The primary feasibility outcomes were screening-to-enrollment ratio and 6-month retention rates; the primary clinical outcome was a change in systolic BP from 0-6 months. RESULTS: Sixty-three participants were enrolled (57% male; mean age: 18 ± 4 years). The screening-to-enrollment ratio was 1.8:1. Six-month retention was 62% in the intervention group and 86% in the control group (p = 0.08). Mean change in systolic BP in the intervention group was not significantly different from the control group at 6 months (- 2.3 mmHg; 95% CI - 6.5, 1.8 vs. 3.0 mmHg; 95% CI - 2.5, 8.4, respectively, p = 0.12). CONCLUSIONS: Among children and young adults at elevated CVD risk, the use of a physical activity tracker coupled with tailored feedback regarding their step count progress was feasible but not sustained over time. Physical activity tracker use did not have a statistically significant effect on BP after 6 months. Augmented strategies to mitigate risk in young patients at high risk for early-onset CVD should be explored. This trial is registered at ClinicalTrials.gov (NCT03325426).