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Young children's physical activity (PA) has been decreasing while their sports participation has been increasing. Therefore, the aim of this research was to longitudinally examine whether and, if so, how organised and non‐organised PA participation by early childhood education and care (ECEC)‐aged children (T1; 3–8 years) predicted their accelerometer‐measured PA at primary school age (T2; 7–11 years). Secondarily, changes in organised and non‐organised PA participation over time were investigated. The cluster‐randomised study participants comprised 501 Finnish children (52.3% girls: T1, Mage = 5.57 ± 1.06; T2, Mage = 8.80 ± 1.07). PA participation was queried via guardian questionnaire at T1 and T2. Organised PA participation was operationalised as non‐participation, participation in one sport or multisport (two or more) participation; non‐organised PA was operationalised as time spent outdoors on weekdays and on weekend days. PA at T2 was measured using accelerometers. The primary outcome was tested using linear regressions, while a paired sample t‐test and Mann–Whitney U test assessed differences between T1 and T2. The results showed outdoor time and organised sports participation increased from T1 to T2. Moreover, outdoor time at T1 predicted more moderate‐to‐vigorous PA (MVPA) and less sedentary time at T2, while multisport participation predicted significantly more MVPA and less sedentary time at T2. Overall, being outdoors and multisport participation at younger ages appear to have predicted Finnish children's later (MV) PA and sedentary behaviour. Highlights: Outdoor time and multisports in early childhood positively predicted subsequent physical activity (PA) in middle childhood.Spending more than 30 min a day outdoors of ECEC hours predicted higher subsequent MVPA and lower sedentary time at school age.Adults promoting outdoor activities and multisports support children to adopt a physically active lifestyle. [ABSTRACT FROM AUTHOR]

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., Play- erLoad, 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. [ABSTRACT FROM AUTHOR]

The quantification of training loads (TLs) is essential for optimizing jump performance and reducing the occurrence of injuries. This study aimed to (a) propose a new method for quantifying TLs in explosive exercises, (b) determine the nature of the relationship between TLs dynamics and injury occurrence, and (c) assess a TLcritical for training schedule purposes, above which the risk of injury occurrence becomes unacceptable. This study was conducted with 11 male volleyball players on a national team during a 5-month international competitive period. The proposed new method for quantifying TLs is based on a weighting factor applied to relative jumping intensities, determined by the number of sustainable jumps and their intensities measured by G-Vert accelerometer. The relationship between TLs dynamics and injury occurrence was assessed using a variable dose-response model. A high coefficient of determination was found between the maximum number of jumps possible and their intensities (r² = 0.94 ± 0.14, p < 0.001), indicating a strong physiological relationship between jumping intensities and the constraints imposed. The occurrence of injury was dependent on TLs dynamics for 2 players (r² = 0.26 ± 0.01; p < 0.001). The TLcritical corresponded to 11 jumps over 80% of maximum jump height during games and approximately 130 jumps at <80% of maximal jump height. The present study proposes a new approach for quantifying supramaximal exercises and provides tools for training schedules and the prevention of volleyball injuries. [ABSTRACT FROM AUTHOR]

Introduction: Physical activity is known to positively influence cognitive performance. For adults with mild cognitive impairment (MCI), the relationship between physical activity levels and cognitive performance is unknown. This cross‐sectional study aimed to determine if cognitive performance [as measured by the Montreal Cognitive Assessment (MoCA)] of people living in the community with MCI is associated with their physical activity levels or sedentary behaviour. Methods: ActivPAL™ accelerometers were used to objectively measure physical activity and sedentary behaviour for seven full days. Cognitive performance was measured using the MoCA. Consumer and Community Involvement: No involvement other than as research participants Results: Eighty‐two participants from the Balance on the Brain randomised controlled trial were included. Most participants were retired (88%), with 33 (40%) reporting a fall in the last year. The median MoCA score was 24 (IQR 22–26). Participants achieved a mean of 6296 (±2420) steps per day and were sedentary for 10.6 (±2) hours per day. The only physical activity outcomes that had a fair, positive correlation were moderate‐ to vigorous‐intensity physical activity measures of total stepping time and total number of steps (with a cadence of ≥100 steps/min) with the orientation MoCA domain score (r(82) = 0.36, p ≤ 0.001 and r(82) = 0.37, p ≤ 0.001, respectively). Higher total sedentary time had a weak, positive correlation with better visuospatial/executive performance (r(82) = 0.23, p = 0.041). The orientation outcomes remained significant when analysed in an adjusted logistic regression model. Conclusion: This study found that performance in the MoCA orientation domain had a fair‐positive correlation with moderate‐intensity physical activity (i.e., stepping time and step count with a cadence of ≥100 steps/min) as measured by a thigh‐worn accelerometer for community‐dwelling older adults with MCI. When considering the relationship between cognitive domains and sedentary behaviour, consideration may be needed regarding whether cognitive enhancing activities (such as crosswords and other brain games) are being performed, which may confound this relationship. Further investigation is required to confirm these results. PLAIN LANGUAGE SUMMARY: Physical activity is good for people of all ages. Regular moderate to vigorous physical activity is known to help memory and thinking skills. Moderate physical activity includes brisk walking, lawn mowing and water aerobics. Vigorous physical activity includes running, fast‐paced swimming, cycling and brisk walking up hills and steps. For adults with mild cognitive impairment (i.e., a person who is starting to have trouble with their memory, but the difficulty is not yet advanced enough to be diagnosed as dementia), we did not know how their level of engagement with physical activity may be related to their memory and thinking skills. A strength of this study is that we had a large population of 82 people living in the community with mild cognitive impairment to review. We found that people who completed more moderate to vigorous physical activity had better skills in remembering the current day, date and place (orientation). [ABSTRACT FROM AUTHOR]

A three-axis seismic accelerometer was developed and created, containing three uniaxial mutually perpendicular sensors, the sensitivity axis of each sensor is located at an angle of 54.736° to the local gravitational vertical. For the first time, additional magnetic rigidity has been introduced into each device, allowing the device to be finely tuned to the conditions of a particular planet. However, the accumulated experience in conducting ground-based tests has shown the need to improve the uniaxial seismic accelerometer, which can significantly improve the characteristics of the device. First, we use a single material—beryllium bronze BrB-2—for the manufacture of massive test mass suspension elements with a thickness of 1.5 mm and an elastic element made of a thin strip 10–20 microns thick, which reduces the likelihood of instability. Secondly, we reduce the gap in the capacitors of capacitive converters from 0.25 to 0.1–0.15 mm to significantly increase the conversion slope of the capacitive sensor. Thirdly, we change the technology of setting up the device, for which we combine all the elements of the sensitive part of a uniaxial seismogravimeter using special vertical inserts. This allows us to place the device as a whole in a system for its configuration, eliminating the possibility of failure of individual elements, thereby increasing the reliability of the device. [ABSTRACT FROM AUTHOR]

Objectives Daily electronic media use, including television viewing and computer use, is common in older adulthood. Yet, increased electronic media usage may disrupt nightly sleep, leading to sleeping fewer hours and more sleep disruptions. The current study examined these relationships in older adulthood, as well as the potential buffering effect of having a regular sleep schedule. Methods Older adults (N  = 273) from the Daily Experiences and Well-Being Study (DEWS) completed 5–6 days of data collection where they answered questions at the beginning of the day about the previous night's sleep as well as questions throughout the day about daily electronic media use. They also wore Actical accelerometers to capture sleep regularity. Results Older adults reported sleeping fewer hours and having more sleep disturbances on days when they reported more instances of computer use. Sleep regularity moderated the daily association between TV viewing and sleep disturbances such that daily TV viewing was associated with more sleep complaints only for older adults who had less regular sleep patterns. However, sleep regularity no longer moderated this association when accounting for napping behavior. Discussion These findings provide evidence that older adults sleep worse after days when they engage in more electronic media use. The association with TV viewing with sleep disturbances on any given day is somewhat mitigated by engaging in regular sleep patterns. Researchers discuss the importance of assessing electronic media use and sleep in daily life as the role of sleep regularity may be a modifiable protective factor. [ABSTRACT FROM AUTHOR]

The elastic modulus of concrete is one of the most important parameters in the analysis and design of concrete structures. However, determining the elastic modulus in civil structures using core-drilled samples is time-consuming and labor-intensive. Additionally, the elastic modulus of Ultra-High Performance Concrete (UHPC) varies significantly depending on its composition. This paper proposes an improved, non-destructive application to identify the elastic modulus of UHPC materials in in-service structures. The elastic modulus is estimated through calibration between a numerical model and experimental UHPC plate vibration test results, using frequency and mode shapes. This calibration involves solving an inverse problem using optimization techniques such as Particle Swarm Optimization (PSO), Genetic Algorithm (GA), Cuckoo Search, and the YUKI algorithm. Updating the plate characteristics is made possible by the development of numerous iterations, where each iteration updates the elastic modulus, thickness, and width values in the term to find the best solution. The highest accuracies compared to experimental data natural frequency values were found in models updated by GA, PSO, YUKI, and Cuckoo algorithms, with errors of 10.77%, 6.58%, 6.87%, and 6.87%, respectively. An experimental sample was tested to determine the elastic modulus of the UHPC, and the proposed application showed a 0.55% error compared to the experimental value. Thus, the estimated elastic modulus value is highly accurate. [ABSTRACT FROM AUTHOR]

Some applications, such as aerospace testing and monitoring the operating conditions of equipment on space missions, require mechanical sensors capable of measuring accelerations at frequencies of several hundred hertz. For such measurements, optomechanical sensors can be used, providing the ability to measure accelerations without calibration. To enable such measurements, improved designs of drum-type sensors with the assigned performance have been elaborated. Such designs make it possible to provide the necessary levels of natural frequencies for optomechanical sensors and eliminate crosstalk. Using mathematical modeling, the dependencies of the mechanical characteristics of the proposed types of acceleration sensors versus their parameters were obtained. The use of such sensor designs ensures their compactness, making their manufacturing more technologically sound and suitable for use, in particular, in space missions. [ABSTRACT FROM AUTHOR]

Well maintained cycleways will encourage more people to cycle, as the condition of cycleways is important for the safety, accessibility and riding comfort of cyclists. Despite that, only a few models used to describe the quality of service for cyclists take the surface condition into account. Objective measuring methods are needed to enable reliable and effective assessment of surface conditions, and measurable performance criteria related to the needs of cyclists should be developed. The purpose of this study has been to test the reliability and validity of using accelerometers in smartphones to assess the riding comfort on cycleways. A smartphone application converting three-dimensional accelerometer measurements into a single indicator for cycleways has been used to assess road surfaces in two field studies, in Sweden and Norway, respectively. Both studies assessed test sections of varying quality. To relate the measurements to subjective riding comfort assessments by cyclists, recruited cyclists collected quantitative data using the app, whilst also rating their perceived riding comfort by completing a survey. Measurements were also related to standard road surface condition indicators, generated from a road surface tester equipped with 19 laser sensors: international roughness index (IRI), mega- and macro-texture. The results show that it is possible to describe the unevenness of a cycleway using the technology present in smartphones. A software application can be used to collect and analyse data from the acceleration sensors in the phone, which can then be used to describe the riding comfort of cyclists. It is mainly the unevenness in the 50-1000 mm size-range that create the greatest discomfort for cyclists, and intermittent vibrations are perceived as more uncomfortable than more evenly distributed vibrations. Therefore, IRI is not a relevant measurement for describing the riding comfort of cyclists. [ABSTRACT FROM AUTHOR]

In this paper, serial elastic actuators (SEAs) in conjunction with an accelerometer are proposed as force sensors to detect the intention of movement, and the SEA is proposed as a gentle actuator of a patient's upper-limb exoskeleton. A smooth trajectory is proposed to provide comfortable performance. There is an offset trajectory between the link and the motor, which increases safety by preventing sudden movements, and the offset is equivalent to the torsional elastic spring constant. The proposed control law is based on a backstepping approach tested in real-time experiments with robust results in a 2-DoF upper-limb rehabilitation exoskeleton. The experimental results showed a sensitivity of 100% and a positive predictive value of 97.5% for movement intention detection. [ABSTRACT FROM AUTHOR]

Background: Understanding how free-ranging animals behave can help in the design of optimal management strategies to both conserve species and enable individuals to express natural behaviours, maximising welfare. Animal-borne accelerometers passively collect data on body acceleration which can be interpreted to quantify behaviour. Accelerometers are increasingly used in behavioural research, however validation of accelerometer readouts to enable classification of discrete behaviours is required for each species. Pangolins are a heavily trafficked clade of mammals, all of which are considered vulnerable to extinction. They are also under-researched, with little known about their behaviour in the wild. In this study, we present the first validation of behavioural classification based on accelerometer readouts for a pangolin species; the ground pangolin (Smutsia temminckii). Results: We present a standardised protocol for attaching accelerometers to pangolins to minimise the impact of devices on welfare. We match the readouts from accelerometers to behaviours defined through video observations. Using a random forest classification, we defined five discrete behaviours (walking, digging, feeding, investigating ground, and stationary, accuracy of 85%) and three activity levels (low, medium, and high, accuracy of 94%) from accelerometer readouts. We determine optimal sampling frequency and window length (50 Hz and five seconds for discrete behaviour, 10 Hz and seven seconds for activity level). We then deploy accelerometers and classify the behaviour of three free-ranging pangolins for between two and four days. We find considerable variation in peak daily activity between free-ranging pangolins with different individuals displaying nocturnal and crepuscular behaviour. We also find that pangolins spend the majority of their time (between 62 and 71%) at rest. Conclusion: The methods we present will enable the quantification of ground pangolin behaviour in the wild to improve our understanding of the species' ecology and help inform conservation efforts. This will also help to improve our fundamental understanding of animal behaviour and ecology. [ABSTRACT FROM AUTHOR]

Predator-prey arms races have led to the evolution of finely tuned disguise strategies. While the theoretical benefits of predator camouflage are well established, no study has yet been able to quantify its consequences for hunting success in natural conditions. We used high-resolution movement data to quantify how barn owls (Tyto alba) conceal their approach when using a sit-and-wait strategy. We hypothesized that hunting barn owls would modulate their landing force, potentially reducing noise levels in the vicinity of prey. Analysing 87,957 landings by 163 individuals equipped with GPS tags and accelerometers, we show that barn owls reduce their landing force as they approach their prey, and that landing force predicts the success of the following hunting attempt. Landing force also varied with the substrate, being lowest on man-made poles in field boundaries. The physical environment, therefore, affects the capacity for sound camouflage, providing an unexpected link between predator-prey interactions and land use. Finally, hunting strike forces in barn owls were the highest recorded in any bird, relative to body mass, highlighting the range of selective pressures that act on landings and the capacity of these predators to modulate their landing force. Overall, our results provide the first measurements of landing force in a wild setting, revealing a new form of motion-induced sound camouflage and its link to hunting success. [ABSTRACT FROM AUTHOR]

Purpose: Devices such as the StepWatch Activity Monitor (SAM) have been available for 20 years and have been shown to accurately measure ambulatory activity. This study aimed to evaluate the agreement among the three generations of the StepWatch Activity Monitor (SW3, SW4, and SW5) with respect to stride count. Methods: A total of 36 participants (age range, 6-55 years) participated in this institutional review board-approved study. The participants concurrently wore three different SAM model devices on the same leg and performed a 6-min walk test (6MWT). A research staff member of the laboratory manually counted the number of strides for the first 2 min of the test (2MWT). Agreement among the device models was evaluated by calculating ANOVAs and interclass correlation coefficients (ICCs) and creating Bland-Altman plots. Results: There was no significant difference among the model versions during the 6MWT and 2MWT (p > 0.05). The ICC for the total stride count was 0.993 (95% CI = 0.988-0.996) during the 2MWT and 0.992 (95% CI = 0.986-0.996) during the 6MWT. There was a near-perfect agreement (ICC = 0.990) of each model version to the manually counted strides during the 2MWT. The systematic bias of all three SAM model versions was <1 step. Conclusions: The results from the present study demonstrate that the stride counts among all three devices are comparable and relative to the manual stride count. All three SAM model versions had an ICC of >0.90. Researchers can safely incorporate historical data from previous SAM model versions with newer data collected with the latest SAM model version. [ABSTRACT FROM AUTHOR]

Protection suits are vital for firefighters' safety. Traditional protection suits physically protect firemen from burns, but cannot locate the position of bodily injuries caused by impact debris. Herein, we present a wearable impact debris positioning system for firefighter protection suits based on an accelerometer array. Wearable piezoelectric accelerometers are distributed regularly on the suit to detect the vibration on different body parts, which is conducive to determining the position of injured body parts. In addition, the injured parts can be displayed on a dummy body model on the upper computer with a higher localization accuracy of 4 cm. The positioning alarm system has a rapid response time of 0.11 ms, attributed to the smart signal processing method. This work provides a reliable and smart method for locating and assessing the position of bodily injuries caused by impact debris, which is significant because it enables fire commanders to rescue injured firefighters in time. [ABSTRACT FROM AUTHOR]

In recent years, there has been an increasing use of digital vibration sensors that are based on capacitive MEMS accelerometers for machine vibration monitoring and diagnostics. These sensors simplify the design of monitoring and diagnostic systems, thus reducing implementation costs. However, it is important to understand how effective these digital sensors are in detecting rolling bearing faults. This article describes a method for determining the diagnostic sensitivity of diagnostic parameters provided by commercially available vibration sensors based on MEMS accelerometers. Experimental tests were conducted in laboratory conditions, during which vibrations from 11 healthy and faulty rolling bearings were measured using two commercial vibration sensors based on MEMS accelerometers and a piezoelectric accelerometer as a reference sensor. The results showed that the diagnostic sensitivity of the parameters depends on the upper-frequency band limit of the sensors, and the parameters most sensitive to the typical fatigue faults of rolling bearings are the peak and peak-to-peak amplitudes of vibration acceleration. Despite having a lower upper-frequency range compared to the piezoelectric accelerometer, the commercial vibration sensors were found to be sensitive to rolling bearing faults and can be successfully used in continuous monitoring and diagnostics systems for machines. [ABSTRACT FROM AUTHOR]

Lack of physical activity (PA) at a young age can result in health issues. Thus, monitoring PA is important. Wearable accelerometers are the preferred tool to monitor PA in children. Validated thresholds are used to classify activity intensity levels, e.g., sedentary, light, and moderate-to-vigorous, in ambulatory children. No previous work has developed accelerometer thresholds for infancy (pre-ambulatory children). Therefore, this work aims to develop accelerometer thresholds for PA intensity levels in pre-ambulatory infants. Infants (n = 10) were placed in a supine position and allowed free movement. Their movements were synchronously captured using video cameras and accelerometers worn on each ankle. The video data were labeled by activity intensity level (sedentary, light, and moderate-to-vigorous) in two-second epochs using observational rating (gold standard). Accelerometer thresholds were developed for acceleration and jerk using two optimization approaches. Four sets of thresholds were developed for dual (two ankles) and for single-worn (one ankle) accelerometers. Of these, for a typical use case, we recommend using acceleration-based thresholds of 1.00 m/s to distinguish sedentary and light activity and 2.60 m/s to distinguish light and moderate-to-vigorous activity. Acceleration and jerk are both suitable for measuring PA. [ABSTRACT FROM AUTHOR]

Vertical drilling is the first stage of petroleum exploitation and directional well technology. The near-vertical attitude at each survey station directly determines the whole direction accuracy of the borehole trajectory. However, the attitude measurement for near-vertical wells has poor azimuth accuracy because the poor signal-to-noise ratio of radial accelerometers hardly obtains the correct horizontal attitude, especially the roll angle. In this paper, a novel near-vertical attitude measurement method was proposed to address this issue. The redundant micro-electromechanical system (MEMS) accelerometers were employed to replace the original accelerometers from MEMS inertial measurement unit (IMU)/magnetometers for calculating horizontal attitude under near-vertical conditions. In addition, a simplified four-position calibration method for the redundant accelerometers was proposed to compensate for the installation and non-orthogonal error. We found that the redundant accelerometers enhanced the signal-to-noise ratio to upgrade the azimuth accuracy at the near-vertical well section. Compared with the traditional method, the experiment results show that the average azimuth errors and roll errors are reduced from 34.45° and 27.09° to 5.7° and 0.61°, respectively. The designed configuration scheme is conducive to the miniaturized design and low-cost requirements of wellbore measuring tools. The proposed attitude measurement method can effectively improve the attitude accuracy of near-vertical wells. [ABSTRACT FROM AUTHOR]

This paper analyzes the influence of three different shape memory alloy (SMA) wires (i.e., Ni-Ti, Cu-Al-Ni, and Cu-Zn wires) for mitigating model cable vibration. Shape memory alloy (SMA) wires because of their superelasticity or shape memory properties can promise to be one of the effective damping materials in suppressing stay cable oscillations. The investigation explores through experimental works, the capabilities of three Ni-Ti, Cu-Al-Ni, and Cu-Zn SMA wires by estimating the vibration amplitude suppression of the model stay cable. The effective location of the SMA wires on the model cable for vibration suppression was estimated in free as well as forced vibration cases. To impart free and forced vibration, respectively, in the cable, a transducer-based hammer and exciter were used. An accelerometer and data acquisition system was used to record and acquire vibration data. It is also very appropriate to ascertain which wire among one of the three SMA wires performs well. It is found that the Ni-Ti SMA wire has a better performance in vibration suppression as compared to Cu-Al-Ni and Cu-Zn wires. It is also established that the attachment of the SMA wire at the mid-length of the cable gives better vibration suppression for the first mode. [ABSTRACT FROM AUTHOR]

To meet the objectives of the Paris Agreement, which aims to limit the increase in global temperature to 1.5°C, significant greenhouse gas (GHG) emission reductions will be needed across all sectors. This includes agriculture which accounts for a significant proportion of global GHG emissions. There is therefore a pressing need for the uptake of new technologies on farms to reduce GHG emissions and move towards current policy targets. Recently, precision livestock farming (PLF) technologies have been highlighted as a promising GHG mitigation strategy to indirectly reduce GHG emissions through increasing production efficiencies. Using Scotland as a case study, average data from the Scottish Cattle Tracing System (CTS) was used to create two baseline beef production scenarios (one grazing and one housed system) and emission estimates were calculated using the Agrecalc carbon footprinting tool. The effects of adopting various PLF technologies on whole farm and product emissions were then modelled. Scenarios included adoption of automatic weigh platforms, accelerometerbased sensors for oestrus detection (fertility sensors) and accelerometer-based sensors for early disease detection (health sensors). Model assumptions were based on validated technologies, direct experience from farms and expert opinion. Adoption of all three PLF technologies reduced total emissions (kg CO2e) and product emissions (kg CO2e/kg deadweight) in both the grazing and housed systems. In general, adoption of PLF technologies had a larger impact in the housed system than in the grazing system. For example, while health sensors reduced total emissions by 6.1% in the housed system, their impact was slightly lower in the grazing system at 4.4%. The largest reduction in total emissions was seen following the adoption of an automatic weight platform which reduced the age at slaughter by 3 months in the grazing system (6.8%) and sensors for health monitoring in the housed system (6.1%). Health sensors also resulted in the largest reduction in product emissions for both the housed (12.0%) and grazing systems (10.5%). These findings suggest PLF could be an effective GHG mitigation strategy for beef systems in Scotland. Although this study utilised data from beef farms in Scotland, comparable emission reductions are likely attainable in other European countries with similar farming systems. [ABSTRACT FROM AUTHOR]

Sleep is essential to life. Accurate measurement and classification of sleep/wake and sleep stages is important in clinical studies for sleep disorder diagnoses and in the interpretation of data from consumer devices for monitoring physical and mental well-being. Existing non-polysomnography sleep classification techniques mainly rely on heuristic methods developed in relatively small cohorts. Thus, we aimed to establish the accuracy of wrist-worn accelerometers for sleep stage classification and subsequently describe the association between sleep duration and efficiency (proportion of total time asleep when in bed) with mortality outcomes. We developed a self-supervised deep neural network for sleep stage classification using concurrent laboratory-based polysomnography and accelerometry. After exclusion, 1113 participant nights of data were used for training. The difference between polysomnography and the model classifications on the external validation was 48.2 min (95% limits of agreement (LoA): −50.3 to 146.8 min) for total sleep duration, −17.1 min for REM duration (95% LoA: −56.7 to 91.0 min) and 31.1 min (95% LoA: −67.3 to 129.5 min) for NREM duration. The sleep classifier was deployed in the UK Biobank with ~100,000 participants to study the association of sleep duration and sleep efficiency with all-cause mortality. Among 66,262 UK Biobank participants, 1644 mortality events were observed. Short sleepers (<6 h) had a higher risk of mortality compared to participants with normal sleep duration 6–7.9 h, regardless of whether they had low sleep efficiency (Hazard ratios (HRs): 1.36; 95% confidence intervals (CIs): 1.18 to 1.58) or high sleep efficiency (HRs: 1.29; 95% CIs: 1.04–1.61). Deep-learning-based sleep classification using accelerometers has a fair to moderate agreement with polysomnography. Our findings suggest that having short overnight sleep confers mortality risk irrespective of sleep continuity. [ABSTRACT FROM AUTHOR]

Background: Both kinematically-aligned (KA) total knee arthroplasty (TKA) and bicruciate stabilized (BCS) TKA aim to reproduce the physiological knee kinematics. In this study, we compared the femoro-tibial component rotational mismatch between patients who underwent modified KA-TKA and those who received guided-motion BCS-TKA, and its influence on the clinical outcomes. Methods: In this retrospective study, 77 consecutive patients were included and divided into two groups: subjects who underwent modified KA-TKA with Persona (KA Group; n = 42) and those who received BCS-TKA with JOURNEY II (BCS group; n = 35). Range of motion, the 2011 Knee Society Score (KSS), the rotational alignment of the femoral and tibial components, and the correlations between the rotational mismatch and the 2011 KSS subscales were examined. Results: The postoperative objective knee indicators (P = 0.0157), patient satisfaction (P = 0.0039) and functional activity scores (P = 0.0013) in the KA group were significantly superior to those in the BCS group 1 year postoperatively. There was no significant difference between the two groups observed in the rotational mismatch. In the BCS group, significant negative correlations were identified between the rotational mismatch and objective indicators, patient satisfaction, and functional activity scores but not in the KA group. Conclusions: The short-term clinical results following KA-TKA showed superior objective knee indicators, patient satisfaction and functional activity scores. A negative correlation was observed between component rotational mismatch and the 2011 KSS subscales in the BCS group, compared to no relationship found between the two in the KA group. These findings suggested that KA-TKA has a relatively higher tolerance for rotational mismatch than BCS-TKA. [ABSTRACT FROM AUTHOR]

Issue Addressed: Referral to supervised physical activity (PA) programs is an effective treatment for military service veterans (MSVs) suffering from a range of chronic diseases. However, many MSVs fail to maintain PA regimes once discharged from supervision. This pilot study assessed Active Choices, a stepped‐down program to support MSVs in the transition from allied health treatment to self‐managed PA. Methods: Participants were 34 Australian MSVs (mean [SD] age = 61 [15.8] years) who were completing supervised referral to an exercise physiologist or physiotherapist. MSVs stepped‐down to Active Choices and received a 12‐week, evidence‐based PA support program (2020–2021). Analyses compared within‐group changes in accelerometer‐assessed PA at three time points (Weeks 0, 12, and 24; linear mixed model). Program retention, PA choices, and allied healthcare service costs were also evaluated. Results: Relative to baseline (64 [26] min/day), mean (SD) moderate‐to‐vigorous PA increased (74 [28] min/day; p <.05) and was maintained (62 [28] min/day) at weeks 12 and 24, respectively. Retention in the program was high (86% [29/34 participants] completion rate at 12 weeks), with water‐based group activities the most popular PAs of choice (14/24 activities). Average allied healthcare service costs during the study were lower than typical costs for MSVs (60.51 vs. 97.06 AUD/week). Conclusion: The findings highlight the potential of Active Choices to support MSVs in the transition from supervised to self‐managed MVPA. So What?: The program could promote the health of veterans and reduce costs for ongoing referral if impact is replicated at scale. [ABSTRACT FROM AUTHOR]

Introduction: Physical activity, sedentary behavior, and sleep, that is, 24-h movement behaviors, often change in the transition from work to retirement, which may affect cardiometabolic health. This study investigates the longitudinal associations between changes in 24-h movement behaviors and cardiometabolic biomarkers during the retirement transition. Methods: Retiring public sector workers (n = 212; mean (SD) age, 63.5 (1.1) yr) from the Finnish Retirement and Aging study used a thigh-worn Axivity accelerometer and filled out a diary to obtain data on daily time spent in sedentary behavior (SED), light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA), and sleep before and after retirement (1 yr in-between). Cardiometabolic biomarkers, including LDL-cholesterol, HDL-cholesterol, total/HDL-cholesterol ratio, triglycerides, C-reactive protein, fasting glucose, and insulin, were measured. Associations between changes in 24-h movement behaviors and cardiometabolic biomarkers were analyzed using compositional robust regression and isotemporal substitution analysis. Results: Increasing LPA in relation to remaining behaviors was associated with an increase in HDL-cholesterol and decrease in total/HDL-cholesterol ratio ( P < 0.05 for both). For instance, reallocation of 30 min from sleep/SED to LPA was associated with an increase in HDL-cholesterol by 0.02 mmol⋅L-1. Moreover, increasing MVPA in relation to remaining behaviors was associated with a decrease in triglycerides ( P = 0.02). Reallocation of 30 min from SED/sleep to MVPA was associated with 0.07-0.08 mmol⋅L-1 decrease in triglycerides. Findings related to LDL-cholesterol, C-reactive protein, fasting glucose, and insulin were less conclusive. Conclusions: During the transition from work to retirement, increasing physical activity at the expense of passive behaviors was associated with a better lipid profile. Our findings suggest that life transitions like retirement could be utilized more as an optimal time window for promoting physical activity and health. [ABSTRACT FROM AUTHOR]

Accelerometers are mainly used to measure the non-conservative forces at the center of mass of gravity satellites and are the core payloads of gravity satellites. All kinds of disturbances in the satellite platform and the environment will affect the quality of the accelerometer data. This paper focuses on the quality assessment of accelerometer data from the GRACE-FO satellites. Based on the ACC1A data, we focus on the analysis of accelerometer data anomalies caused by various types of disturbances in the satellite platform and environment, including thruster spikes, peaks, twangs, and magnetic torque disturbances. The data characteristics and data accuracy of the accelerometer in different operational states and satellite observation modes are analyzed using accelerometer observation data from different time periods. Finally, the data consistency of the accelerometer is analyzed using the accelerometer transplantation method. The results show that the amplitude spectral density of three-axis linear acceleration is better than the specified accuracy (above 10−1 Hz) in the accelerometer's nominal status. The results are helpful for understanding the characteristics and data accuracy of GRACE-FO accelerometer observations. [ABSTRACT FROM AUTHOR]

Anti-gravity treadmills have been used in rehabilitation to manipulate exposure to loading and to prescribe return to outside running. Analysis is typically restricted to the vertical plane, but tri-axial accelerometry facilitates multi-planar analysis with relevance to injury mechanism. In this case a professional male soccer player, 4 weeks post-operative surgery to repair a medial meniscectomy, 8 months after Anterior Cruciate Ligament reconstruction to the same knee, completed anti-gravity treadmill running at 70–95% bodyweight (BW) at 5% increments. Tri-axial accelerometers were placed proximal to the Achilles tendon of the injured and healthy leg, and at C7. The planar acceleration at touchdown highlighted an increase at 85% BW, identifying 70% and 85% BW as discrete loading progressions. C7 (3.21 ± 0.68 m·s−2) elicited lower (P < 0.001) vertical acceleration than the lower limb (9.31 ± 1.82 m·s−2), with no difference between limbs suggesting bilateral symmetry. However, in the medio-lateral plane the affected limb (−0.15 ± 1.82 m·s−2) was exposed to lower (P = 0.001) medio-lateral acceleration than the non-affected limb (2.92 ± 1.35 m·s−2) at touchdown, indicative of bilateral asymmetry. PlayerLoad during foot contact was sensitive to accelerometer location, with the affected limb exposed to greater loading in all planes (P ≤ 0.082), exacerbated at 90–95% BW. Tri-axial accelerometry provides a means of assessing multi-planar loading during rehabilitation, enhancing objective progression. [ABSTRACT FROM AUTHOR]

The beneficial effects of physical activity (PA) on gut microbiome have been reported, nevertheless the findings are inconsistent, with the main limitation of subjective methods for assessing PA. It is well accepted that using an objective assessment of PA reduces the measurement error and also allows objective assessment of sedentary behavior (SB). We aimed to study the associations between accelerometer‐assessed behaviors (i.e., SB, light‐intensity physical activity [LPA] and moderate‐to‐vigorous physical activity [MVPA]) with the gut microbiome using compositional data analysis, a novel approach that enables to study these behaviors accounting for their inter‐dependency. This cross‐sectional study included 289 women from the Northern Finland Birth Cohort 1966. Physical activity was measured during 14 days by wrist‐worn accelerometers. Analyses based on the combined effect of MVPA and SB, and compositional data analyses in association with the gut microbiome data were performed. The microbial alpha‐ and beta‐diversity were not significantly different between the MVPA‐SB groups, and no differentially abundant microorganisms were detected. Compositional data analysis did not show any significant associations between any movement behavior (relative to the others) on microbial alpha‐diversity. Butyrate‐producing bacteria such as Agathobacter and Lachnospiraceae CAG56 were significantly more abundant when reallocating time from LPA or SB to MVPA (γ = 0.609 and 0.113, both p‐values = 0.007). While PA and SB were not associated with microbial diversity, we found associations of these behaviors with specific gut bacteria, suggesting that PA of at least moderate intensity (i.e., MVPA) could increase the abundance of short‐chain fatty acid–producing microbes. [ABSTRACT FROM AUTHOR]

Using smartphones, we aimed to clarify the characteristics of anticipatory postural adjustments (APA) in older adults and examine the relationship between cognitive and balance functions. The study participants were 10 young and 13 older adults. An accelerometer built into a smartphone was attached to the lower back (L5) of the participant, and acceleration in the mediolateral direction was measured using a one-leg stance (OLS). As APA features, we analyzed the time to the peak value in the stance direction (peak latency [PL]) and the amount of displacement to the peak value in the stance direction (peak magnitude [PM]). Additionally, the measured PL was divided by PM for each group to obtain the APA ratio (APAr). We investigated the relationship between the APAr and Mini-BESTest subitems. Older adults showed delayed PL and decreased PM levels (p < 0.01). While in the Mini-BESTest sub-items, deductions were most common in the order of dual-task and single-leg standing, and most participants with low APAr scores were degraded in APA of sub-items. The correlation was observed between APAr and both TUG and dual-task cost (DTC) (r= −0.56, r= −0.67). According to the receiver operating characteristic curve, the APAr value was 1.71 in the older age group. Older adults showed delayed PL and decreased PM, and APAr was associated with cognitive and locomotor functions. By evaluating the APAr at the initiation of movement, it may be possible to distinguish the APA of the older adluts from the possible to the impossible of OLS movement. • Anticipatory postural adjustments (APA) were compared in older and young adults. • PL and PM of lumbar acceleration in one-leg stance were used for evaluation of APA. • Older adults show delayed peak latency(PL) and decreased peak magnitude(PM). • The characteristic values of APA is associated with cognitive and balance functions. • APA evaluation is useful as an index reflecting cognitive motor-processing function. [ABSTRACT FROM AUTHOR]

Accelerometers are used to objectively measure physical activity; however, the relationship between accelerometer-based activity parameters and bone health is not well understood. This study examines the association between accelerometer-estimated daily activity impact intensities and future risk estimates of major osteoporotic fractures in a large population-based cohort. Participants were 3165 adults 46 years of age from the Northern Finland Birth Cohort 1966 who agreed to wear a hip-worn accelerometer during all waking hours for 14 consecutive days. Raw accelerometer data were converted to resultant acceleration. Impact magnitude peaks were extracted and divided into 32 intensity bands, and the osteogenic index (OI) was calculated to assess the osteogenic effectiveness of various activities. Additionally, the impact peaks were categorized into three separate impact intensity categories (low, medium, and high). The 10-year probabilities of hip and all major osteoporotic fractures were estimated with FRAX-tool using clinical and questionnaire data in combination with body mass index collected at the age of 46 years. The associations of daily activity impact intensities with 10-year fracture probabilities were examined using three statistical approaches: multiple linear regression, partial correlation, and partial least squares (PLS) regression. On average, participants' various levels of impact were 8331 (SD = 3478) low; 2032 (1248) medium; and 1295 (1468) high impacts per day. All three statistical approaches found a significant positive association between the daily number of low-intensity impacts and 10-year probability of hip and all major osteoporotic fractures. In contrast, increased number of moderate to very high daily activity impacts was associated with a lower probability of future osteoporotic fractures. A higher OI was also associated with a lower probability of future major osteoporotic fractures. Low-intensity impacts might not be sufficient for reducing fracture risk in middle-aged adults, while high-intensity impacts could be beneficial for preventing major osteoporotic fractures. • Free-living daily activity impacts were calculated from hip-worn accelerometry. • Associations of daily activity impact intensities with fracture risk was examined. • Three statistical methods were used to assess the associations with fracture risk. • Low-intensity impacts might not be sufficient for reducing fracture risk in adults. • High-intensity impacts could be beneficial for reducing osteoporotic fracture risk. [ABSTRACT FROM AUTHOR]

To improve the accuracy of monthly temporal gravity field models for the Gravity Recovery and Climate Experiment (GRACE) and the GRACE Follow-On (GRACE-FO) missions, a new series named HUST-Grace2024 is determined based on the updated L1B datasets (GRACE L1B RL03 and GRACE-FO L1B RL04) and the newest atmosphere and ocean de-aliasing product (AOD1B RL07). Compared to the previous HUST temporal gravity field model releases, we have made the following improvements related to updating the background models and the processing chain: (1) during the satellite onboard events, the inter-satellite pointing angles are calculated to pinpoint outliers in the K-band ranging (KBR) range-rate and accelerometer observations. To exclude outliers, the advisable threshold is 50 mrad for KBR range rates and 20 mrad for accelerations. (2) To relieve the impacts of KBR range-rate noise at different frequencies, a hybrid data-weighting method is proposed. Kinematic empirical parameters are used to reduce the low-frequency noise, while a stochastic model is designed to relieve the impacts of random noise above 10 mHz. (3) A fully populated scale factor matrix is used to improve the quality of accelerometer calibration. Analyses in the spectral and spatial domains are then implemented, which demonstrate that HUST-Grace2024 yields a noticeable reduction of 10 % to 30 % in noise level and retains consistent amplitudes of signal content over 48 river basins compared with the official GRACE and GRACE-FO solutions. These evaluations confirm that our aforementioned efforts lead to a better temporal gravity field series. This data set is identified with the following DOI: 10.5880/ICGEM.2024.001 (Zhou et al., 2024). [ABSTRACT FROM AUTHOR]

Background: About half of preschool‐age children are not meeting recommendations of 15 min/h of physical activity (PA), and nearly one out of seven children between the ages of 2–5 years are living with obesity. Furthermore, children attending family child care homes (FCCHs), compared with larger child care centers, engage in lower levels of PA and appear to be at a higher risk of obesity. Therefore, examining PA and multi‐level factors that influence PA in children who attend FCCHs is essential. Methods: The Childcare Home Eating and Exercise Study (CHEER) examined PA behaviors of 184 children enrolled in 56 FCCHs and FCCH quality status, environment and policy features, and child characteristics. PA was assessed by accelerometer, and FCCH environment and policy was assessed via structured observation. Multiple linear regression was used to model associations between school day total PA and FCCH quality status, environment and policy features, and child characteristics. Results: Child participants were on average 3.1 years old; participants were non‐Hispanic Black (47.3%), Non‐Hispanic White (42.9%), other race/ethnicity (7.1%), and Hispanic/Latin (2.7%). Children in FCCH settings participated in 11.2 min/h of total PA, which is below the recommended 15 min per hour. The PA environment and policy observation yielded a score of 11.8 out of a possible 30, which is not supportive of child PA. There were no associations between total child PA and FCCH quality status, environment and policy features, and child characteristics in these FCCH settings. Conclusions: This study was unique in its examination of PA and a comprehensive set of factors that may influence PA at the individual, organizational, environmental, and policy levels in a diverse sample of children attending FCCHs in South Carolina. Additional research is needed to better understand how to increase children's physical activity while they are in the FCCH setting. This research should use multi‐level frameworks and apply longitudinal study designs. [ABSTRACT FROM AUTHOR]

Objective: The aim was to (1) estimate the relationship between physical fitness (PF) and object control fundamental movement skills (FMS), (2) identify child characteristics that relate with PF and FMS, and (3) examine associations between the school environment, PF, and FMS. Methods: The sample included 1014 Portuguese children aged 6–10 years from the REACT project. PF was assessed via running speed, shuttle run, standing long jump, handgrip, and the PACER test. Object control FMS were assessed with stationary dribble, kick, catch, overhand throw, and underhand roll. Test performances were transformed into z‐scores, and their sum was expressed as overall PF and FMS. Child‐level variables included body mass index (BMI) z‐scores, accelerometer‐measured sedentary time and moderate‐to‐vigorous physical activity, and socioeconomic status (SES). School size, physical education classes, practice areas, and equipment were also assessed. Results: Approximately, 90% of the variance in object control PF and FMS was at the child level, and 10% at the school level. The correlation between PF and object control FMS was.62, which declined to.43 with the inclusion of covariates. Older, more active, and higher SES children had higher object control PF and FMS, and boys outperformed girls. BMI was negatively associated with PF but not with object control FMS. Sedentary time and number of physical education classes were not significant predictors. Most school predictors did not jointly associate with PF and object control FMS. Conclusion: PF and object control FMS z‐scores were moderately related. Not all child characteristics were associated with both PF and object control FMS, and their effect sizes were different. School characteristics only explained 10% of the total variation in PF and object control FMS. [ABSTRACT FROM AUTHOR]

Monitoring training load is essential for optimizing the performance of athletes, allowing practitioners to assess training programs, monitor athlete progress, and minimize the risk of injury and overtraining. However, there is no universal method for training load monitoring, and the adoption of wearable global positioning system (GPS) and accelerometer technology in team sports has increased the volume of data and, therefore, the number of possible approaches. This survey investigated the usage, applications, and understanding of this technology by team sports practitioners. Seventy-two practitioners involved in team and athlete performance monitoring using GPS and accelerometer technology completed the survey. All respondents reported supporting the use of GPS technology in their sport, with 70.8% feeling that GPS technology is important for success. Results showed that 87.5% of respondents use data from wearable technology to inform training prescription, although only 50% use the data to influence decisions in competition. In addition, results showed that GPS metrics are used more than accelerometer-derived metrics; however, both are used regularly. Discrepancies in accelerometer usage highlighted concerns about practitioners' understanding of accelerometer-derived metrics. This survey gained insight into usage, application, understanding, practitioner needs, and concerns and criticisms surrounding the use of GPS and accelerometer metrics for athlete load monitoring. Such information can be used to improve the implementation of this technology in team sport monitoring and highlight gaps in the literature that will help to design future studies to support practitioner needs. [ABSTRACT FROM AUTHOR]

Introduction: Physical activity (PA) has shown great benefits in patients with chronic obstructive pulmonary disease (COPD); however, their PA is below average. Motivational factors associated with PA in COPD have not been widely studied and could be a target for improving adherence to PA. The objective of our study was to identify and understand the different motivational and confidence factors related to low levels of PA in a COPD cohort. Method: Observational, prospective, multicenter study of COPD patients. Sociodemographic data, respiratory symptoms, comorbidities, spirometry, and exercise capacity were collected. PA was measured using the Dynaport accelerometer and patient motivation and confidence in PA were assessed by a questionnaire previously used in a COPD population in the USA. Results: Eighty six COPD patients were included, 68.6% being male, with a mean (SD) age of 66.6 (8.5) years and a mean forced expiratory volume in the first second (%) of 50.9% (17.3%). The mean walking time was 82.8 (37.8) minutes/day. Questions related to health benefits and enjoying exercise were ranked highest in the motivation questionnaire and statistically significant differences were found in PA measures between patients with low and high motivation. A lack of confidence regarding hot weather and health-related issues significantly influenced PA levels. Advice from third parties, including healthcare providers, was not associated with higher PA levels. Conclusions: Improving the health of COPD patients is their main motivation to perform PA. Lack of confidence when it is hot or when they fear for their health is related to low levels of PA. Advice from third parties, including healthcare professionals, is not associated with higher PA. These results are relevant for developing strategies to increase the adherence of COPD patients to PA programs. [ABSTRACT FROM AUTHOR]

Continuous exposure to hand-arm vibration integrated with poor posture and forceful movements are known causes of musculoskeletal disorders (MSD). In most related studies, force and vibration levels in experimental research is controlled. This study aims to determine how actual hand tractor field operation can affect the upper limb of users. It intends to characterize upper limb muscle activation applied during actual hand tractor usage. Lastly, it determines the immediate impacts on hand strength and perceived upper limb discomfort after the operation. We recruited 15 farm operators with a mean working experience of 20.1 ± 12.2 years. They were asked to operate a hand tractor on paddy fields for at most 8 minutes. Handle vibration was measured using a tri-axial accelerometer. The total unweighted vibration acceleration was computed and used to represent the handle vibration magnitude. Muscle activation was measured using surface electromyography (sEMG). Six sEMG sensors were attached to the dominant and non-dominant side of the extensor carpi radialis (ECR), bicep, and deltoid. Pre- and post-task hand strength and subjective discomfort rating were also taken. The total unweighted handle vibration acceleration is 17.45 ± 7.53 m/s2. This exceeds the allowable safe value. Meanwhile, the percentage of maximum voluntary contraction (% MVC) of the muscles ranged from 6% to 14% with the ECR having a significantly higher activation (p <.05) than the bicep and deltoid. The post-task grip strength of the dominant hand was lower than its pre-task value (p <.01) while that of the non-dominant side did not vary significantly. There is a modest trend of higher hand discomfort of the non-dominant side on post-task than pre-task rating (p <.10). Although, overall, the perceived discomfort ranged from none to mild discomfort. In conclusion, the study showed an indication that the effects of vibration on humans are evident even at mild muscle exertion, with the exertion predominantly concentrated on the distal arm area clearly affecting grip strength and hand discomfort. In such cases, future recommendations can revolve around the improvement of the hand tractor handle grip to impose grip comfort and ease. [ABSTRACT FROM AUTHOR]

Latent Class Analysis (LCA) is a statistical method that can help researchers interested in better understanding the movement behaviors (MB) of children, based on the analysis of the level of physical activity (PA) and sedentary time (ST). This study aimed to evaluate and compare two models LCA (one for the accelerometer and one for the 24-hour recall) that represent the MB of children. A cross-sectional study involving 101 10-year-old Brazilian children. The classes were based on vigorous PA (VPA), moderate PA (MPA), light PA (LPA), and sedentary time (ST). To assess these behaviors, a 24-hour recall and an accelerometer were used. The accelerometer was used during four days. The time spent on each of the MB was categorized dichotomously, based on the 25th and 75th percentiles. Thus, "adequate" times were considered when the ST was below 25thP, the LPA and MPA were above 25thP and the VPA was above 75thP. LCA was used to model the variable "MB." For each latent class model (accelerometer and recall), two classes were found: "Adequate MB" and "Inadequate MB." Regardless of the method (accelerometer or self-report), the values of the "Inadequate MB" class had higher prevalence. Self-report predicted higher PA and lower ST compared to the accelerometer. The model based on accelerometry revealed that girls were 2.11 times more likely to belong to the "Inadequate MB" class when compared to boys. LCA was a multivariate statistical method that allowed the integrated evaluation of parameters that represent the MB analyzed by device-based and self-report methods. [ABSTRACT FROM AUTHOR]

In this paper, we present an unscented Kalman filter (UKF) for fusion of information from an accelerometer, global navigation satellite system (GNSS) instrumentation, and rotational sensor recordings of structural motion. Seismic and structural motions do not only include translations, but further incorporate torsion and twisting of the ground and/or structural components. Accelerometer and GNSS positions are known to be prone to errors introduced by rotation, such as (1) gravitational leakage, (2) misorientation, and (3) antenna pole tilt. In alleviating such effects, we propose fusion of information from six component (6C) data—3C translation and 3C rotation—and demonstrate its applicability for motion tracking on a flexible pedestrian bridge. To simulate a variety of load effects, the bridge was subjected to various sources of excitation such as hammer impulses, jumping, twisting, and running, as well as a combination thereof named the "artificial coupled forcing." The rotation errors of both the accelerometer and GNSS-estimated positions are corrected via a UKF-based fusion. We further identify the modal properties of the monitored bridge, excited by the different excitation sources, using a covariance driven stochastic subspace identification. The twisting of the bridge is shown to be a primary source of rotation errors. These errors ought to be corrected because their order of magnitude can be as large as the actual signal in the case of GNSS positions and up to 10% for accelerometer sensors. We compare the proposed UKF-based fusion for 6C motion tracking against a simplified linear Kalman filter and demonstrate the potential of the former for real-time, broadband, rotation-free displacement, velocity, and rotations tracking. [ABSTRACT FROM AUTHOR]

Drivers with ADHD are at greater risk for road accidents and are more prone to traffic violations and risky driving than drivers without ADHD. However, no study has tested if the greater risk of drivers with ADHD generalises to a population of professional drivers that are monitored by their supervisors. We investigated the driving behaviour of transport military drivers with and without ADHD (25 and 146, respectively) based on the reports from an Advanced Driving Assistance System. Results indicated that safety events were significantly more frequent for drivers with ADHD than for drivers without ADHD. Notably, the most significant difference was for speeding violations with a Relative Risk (RR) of 2.13 (113% increase). We conclude that the riskier driving of drivers with ADHD remains even among professional drivers that are monitored by their supervisors. Perhaps drivers with ADHD might benefit from customised intervention programmes. CCS CONCEPTS • Applied computing → Operations research → Transportation • Computer systems organisation → Real-time systems. [ABSTRACT FROM AUTHOR]

Background: Chinese American immigrants have been underrepresented in health research partly due to challenges in recruitment. Objectives: This study aims to describe recruitment and retention strategies and report adherence in a 7-day observational physical activity study of Chinese American immigrants with prior gestational diabetes during the COVID-19 pandemic. Methods: Foreign-born Chinese women aged 18--45 years, with a gestational diabetes index pregnancy of 0.5--5 years, who were not pregnant and had no current diabetes diagnosis were recruited. They wore an accelerometer for 7 consecutive days and completed an online survey. Multiple recruitment strategies were used: (a) culturally and linguistically tailored flyers, (b) social media platforms (e.g., WeChat [a popular Chinese platform] and Facebook), (c) near-peer recruitment and snowball sampling, and (d) a study website. Retention strategies included flexible scheduling and accommodation, rapid communications, and incentives. Adherence strategies included a paper diary and/or automated daily text reminders with a daily log for device wearing, daily email reminders for the online survey, close monitoring, and timely problem-solving. Results: Participants were recruited from 17 states; 108 were enrolled from August 2020 to August 2021. There were 2,479 visits to the study webpage, 194 screening entries, and 149 inquiries about the study. Their mean age was 34.3 years, and the mean length of U.S. stay was 9.2 years. Despite community outreach, participants weremainly recruited fromsocialmedia (e.g., WeChat). The majority were recruited via near-peer recruitment and snowball sampling. The retention rate was 96.3%; about 99% had valid actigraphy data, and 81.7% wore the device for 7 days. The majority of devices were successfully returned, and the majority completed the online survey on time. Discussion: We demonstrated the feasibility of recruiting and retaining a geographically diverse sample of Chinese American immigrants with prior gestational diabetes during the COVID-19 pandemic. Recruiting Chinese immigrants via social media (e.g., WeChat) is a viable approach. Nonetheless, more inclusive recruitment strategies are needed to ensure broad representation from diverse socioeconomic groups of immigrants. [ABSTRACT FROM AUTHOR]

Objectives: To explore the relationship between sleep duration and cognitive functions in older adults using NHANES, a national US population study dataset, and to explore the causal association with Mendelian randomization (MR) using the UK Biobank. Methods: First, an observational study was conducted with the NHANES database with participants ≥60 years. Sleep duration was measured with accelerometers for 7 consecutive days. Participants were divided into habitual short sleep (<7 h) and long sleep (>9 h) groups. Cognitive functions were measured with the CERAD Word Learning sub-set, Animal Fluency, and Digit Symbol Substitution test (DSST). Multivariate regression models were used to explore relationships between sleep duration and cognitive functions. Second, bidirectional MR was conducted with data for self-reported sleep duration, which came from a genome-wide association study (GWAS) comprising 446,118 adults from the UK Biobank, and general cognitive performance, which was obtained from a recent GWAS study (N = 257,841). Inverse-variance weighted (IVW) was used as the primary estimation of the outcome. Results: In the observational study, 2687 participants were included. Sleep duration was associated with cognitive functions in a non-linear way. Habitual long sleep (>9°h) was associated with lower scores on DSST (OR = 0.01, p =.003) in the fully-adjusted model. The association between habitual short sleep and cognitive functions was insignificant. For the MR, genetically predicted lower general cognitive performance was causally associated with a higher prevalence of habitual short sleep (OR = 0.97, p = 5.1 × 10−7) and long sleep (OR = 0.97, p = 8.87 × 10−16). Discussion: Short and long sleep duration might be both causally associated with worse outcomes of cognitive functions in older adults, highlighting the importance of maintaining sleep health. [ABSTRACT FROM AUTHOR]

The article informs about the differences in quadriceps and hamstrings activation during repeated hops among athletes who underwent ACL reconstruction, emphasizing the need for nuanced assessment methods to detect these differences and ensure proper rehabilitation. Topics include the challenges athletes face after ACL reconstruction, the use of surface electromyography (SEMG) for neuromuscular analysis, and the importance of timing and magnitude of muscle activation in rehabilitation protocols.

• Gender inequalities in youth physical activity are not explained by country/region-level school uniform policies. Findings remain consistent when analyses are restricted to device-measured data. • However, among primary school-aged children, greater gender inequalities in physical activity are observed in countries/regions where school uniforms are common. • The association between school uniform policies and gender inequalities in youth physical activity is largest in high-income countries/regions. • Compliance with physical activity guidelines is lower in countries/regions where school uniforms are common compared to countries/regions where uniforms are less commonly worn. It is aimed to assess whether school uniforms are associated with population-level gender inequalities in physical activity, and whether associations differ by school level, country/region income, and assessment method. An ecological study design was employed. We collected data about global uniform practices using an online survey. We searched for country/region-level estimates of school-aged youth meeting physical activity guidelines from international surveillance studies. Study selection was conducted in duplicate using a systematic process, and a random sample of all data was checked to ensure extraction and pooling processes were accurate. We calculated absolute and relative gender inequalities in physical activity for each country. Linear regression examined associations between country/region-level uniform practices (binary yes/no exposure variable) and country/region-level gender inequalities in physical activity guideline compliance (absolute and relative inequalities). We investigated moderation by school level, stratified analyses by income group, and repeated primary analyses using device-measured data. Pooling data from 135 countries/regions (n = 1,089,852), we found no association between population-level uniform practices and gender inequalities in physical activity across all ages (absolute: β = –0.2; 95% confidence interval (95%CI): –1.7 to 1.3, p = 0.74; relative: β = 0.1; 95%CI: –0.1 to 0.2, p = 0.51). Subgroup analysis suggested a positive association in primary school settings (absolute: β = 4.3; 95%CI: –0.0 to 8.6, p = 0.05). Among high-income countries, absolute inequalities were significantly greater in countries/regions with uniform practices (N = 37) compared to those without (N = 48) (9.1 (SD = 3.6) vs. 7.8 percentage points (SD = 4.3)). Repeating analyses using device-measured data (n = 32,130; N = 24) did not alter our primary finding. From initial descriptive statistics, we found that in countries/regions where a majority of schools (>50%) reportedly use uniforms, there was lower compliance with physical activity guidelines among all genders (median: 16.0%, interquartile range: 13.2%–19.9%, N = 103) compared to generally non-uniform countries/regions (median: 19.5%, interquartile range: 16.4%–23.5%, N = 32) (z = 3.04, p = 0.002). (N = countries, regions and studies represented; n = sample size or participants included). School uniforms are associated with greater gender inequalities in physical activity in primary school settings and in high-income countries. Our population-level findings warrant testing using individual-level data across contexts. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, we examine security for edge AI devices that detect anomaly behavior due to machine failures. Typical edge AI devices perform only inference, but the inference accuracy may be degraded when sensing data changes depending on the environment in which the devices are deployed. One countermeasure against this problem is on-device learning, in which an AI updates its learning model in accordance with its environment. However, on-device learning AIs face a variety of security threats: for example, the correct inference cannot be performed if the deployed AI model is manipulated by the attacker. Although threats including invasive/non-invasive attacks via physical access have been mentioned in the past, relatively few reports have investigated experimental attacks. In this work, we demonstrated data poisoning by exploiting physical attacks on sensors implemented on edge AI. A system for detecting abnormal vibrations was evaluated using an autoencoder that utilizes sensing data from an accelerometer attached to a cooling fan as input. Accelerometer values can be tampered with during an acoustic wave injection attack, so we exploited this kind of attack. The anomaly detector that learned the tampered data could not detect abnormal fan vibrations correctly. [ABSTRACT FROM AUTHOR]

This paper presents a micromachined thermal convective accelerometer with low power and high reliability. This accelerometer comprises a heater and two thermistors. The central heater elevates the temperature of the chip above ambient levels while the symmetrically arranged thermistors monitor the temperature differentials induced by acceleration. The heater and thermistors are fabricated on a glass substrate using a standard micro-electromechanical systems (MEMS) process flow, and the fabricated sensor is installed on a rotation platform and a shaking table experimental setup to perform the experiment. The results indicate that the sensor has the capability to measure accelerations surpassing 80 m/s2, with an approximate linear sensitivity of 110.69 mV/g. This proposed thermal convective accelerometer offers promising potential for various applications requiring precise acceleration measurements in environments where low power consumption and high reliability are paramount. [ABSTRACT FROM AUTHOR]

This study proposes a fusion algorithm based on forward linear prediction (FLP) and particle swarm optimization–back propagation (PSO-BP) to compensate for the temperature drift. Firstly, the accelerometer signal is broken down into several intrinsic mode functions (IMFs) using variational modal decomposition (VMD); then, according to the FE algorithm, the IMF signal is separated into mixed components, temperature drift, and pure noise. After that, the mixed noise is denoised by FLP, and PSO-BP is employed to create a model for temperature adjustment. Finally, the processed mixed noise and the processed IMFs are rebuilt to obtain the enhanced output signal. To confirm that the suggested strategy works, temperature experiments are conducted. After the output signal is processed by the VMD-FE-FLP-PSO-BP algorithm, the acceleration random walk has been improved by 23%, the zero deviation has been enhanced by 24%, and the temperature coefficient has been enhanced by 92%, compared with the original signal. [ABSTRACT FROM AUTHOR]

This study adopted a quasi-experimental design to explore the effects of fundamental movement skill intervention on the acquisition and retention of physical activity levels and health-related fitness in children with autism spectrum disorder (ASD). In the experiments, 11 children received fundamental motor skill training (12 weeks, 60 min/session, 4 times/week), and 10 children maintained traditional physical activity. Assessments were performed using an ActiGraph GT3X+ accelerometer, health-related fitness pre–post intervention, and 1-month follow-up tests. The sedentary time during physical activity was significantly decreased (p = 0.01), and there were large changes in health-related physical fitness indicators, including significantly improved body composition (body mass index, F(1,19) = 8.631, p = 0.03, partial η2 = 0.312), muscle strength and endurance (sit-ups, F(1,19) = 3.376, p = 0.02, partial η2 = 0.151 and vertical jumps, F(1,19) = 5.309, p = 0.04, partial η2 = 0.218), and flexibility (sit and reach, F(1,19) = 36.228, p = 0.02, partial η2 = 0.656). Moreover, the follow-up tests showed that the children's sedentary time continued to reduce, and the muscle strength and endurance (sit-ups, F(1,19) = 4.215, p = 0.01, partial η2 = 0.426) improved continuously after the intervention. Based on this study, actionable and regular fundamental movement skill programs can be provided in the future as an effective way to achieve the healthy development goals of children with ASD. [ABSTRACT FROM AUTHOR]

We tested whether spontaneous physical activity (SPA) from accelerometers could be used in a whole room calorimeter to estimate thermic effect of food (TEF). Eleven healthy participants (n = 7 females; age: 27 ± 4 yr; body mass index: 22.8 ± 2.6 kg/m2) completed two 23-h visits in randomized order: one "fed" with meals provided and one "fasted" with no food. SPA was measured by ActivPAL and Actigraph accelerometers. Criterion TEF was calculated as the difference in total daily energy expenditure (TDEE) between fed and fasted visits and compared with three methods of estimating TEF: 1) SPA-adjusted TEF (adjTEF)—difference in TDEE without SPA between visits, 2) Wakeful TEF—difference in energy expenditure obtained from linear regression and basal metabolic rate during waking hours, 3) 24-h TEF—increase in TDEE above SPA and sleeping metabolic rate. Criterion TEF was 9.4 ± 4.5% of TDEE. AdjTEF (difference in estimated vs. criterion TEF: activPAL: −0.3 ± 3.3%; Actigraph: −1.8 ± 8.0%) and wakeful TEF (activPAL: −0.9 ± 6.1%; Actigraph: −2.8 ± 7.6%) derived from both accelerometers did not differ from criterion TEF (all P > 0.05). ActivPAL-derived 24-h TEF overestimated TEF (6.8 ± 5.4%, P = 0.002), whereas Actigraph-derived 24-h TEF was not significantly different (4.3 ± 9.4%, P = 0.156). TEF estimations using activPAL tended to show better individual-level agreement (i.e., smaller coefficients of variation). Both accelerometers can be used to estimate TEF in a whole room calorimeter; wakeful TEF using activPAL is the most viable option given strong group-level accuracy and reasonable individual agreement. NEW & NOTEWORTHY: Two research-grade accelerometers can effectively estimate spontaneous physical activity and improve the estimation of thermic effect of food (TEF) in whole room calorimeters. The activPAL demonstrates strong group-level accuracy and reasonable individual-level agreement in estimating wakeful TEF, whereas a hip-worn Actigraph is an acceptable approach for estimating 24-h TEF. These results highlight the promising potential of accelerometers in advancing energy balance research by improving the assessment of TEF within whole room calorimeters. [ABSTRACT FROM AUTHOR]

This paper presents a non-invasive methodology for structural health monitoring (SHM) integrated with inertial sensors and signal conditioning techniques. The proposal uses the signal of an IMU (inertial measurement unit) tri-axial accelerometer and gyroscope to continuously measure the displacements of a structure in motion due to seismic vibrations. A system, called the "Inertial Displacement Monitoring System" or "IDMS", is implemented to attenuate the signal error of the IMU with methodologies such as a Kalman filter to diminish the influence of white noise, a Chebyshev filter to isolate the frequency values of a seismic motion, and a correction algorithm called zero velocity observation update (ZVOB) to detect seismic vibrations and diminish the influence of external perturbances. As a result, the IDMS is a methodology developed to measure displacements when a structure is in motion due to seismic vibration and provides information to detect failures opportunely. [ABSTRACT FROM AUTHOR]

Background: Accelerometers were traditionally worn on the hip to estimate energy expenditure (EE) during physical activity but are increasingly replaced by products worn on the wrist to enhance wear compliance, despite potential compromises in EE estimation accuracy. In the older population, where the prevalence of hearing loss is higher, a new, integrated option may arise. Thus, this study aimed to investigate the accuracy and precision of EE estimates using an accelerometer integrated into a hearing aid and compare its performance with sensors simultaneously worn on the wrist and hip. Methods: Sixty middle-aged to older adults (average age 64.0 ± 8.0 years, 48% female) participated. They performed a 20-min resting energy expenditure measurement (after overnight fast) followed by a standardized breakfast and 13 different activities of daily living, 12 of them were individually selected from a set of 35 activities, ranging from sedentary and low intensity to more dynamic and physically demanding activities. Using indirect calorimetry as a reference for the metabolic equivalent of task (MET), we compared the EE estimations made using a hearing aid integrated device (Audéo) against those of a research device worn on the hip (ZurichMove) and consumer devices positioned on the wrist (Garmin and Fitbit). Class-estimated and class-known models were used to evaluate the accuracy and precision of EE estimates via Bland-Altman analyses. Results: The findings reveal a mean bias and 95% limit of agreement for Audéo (class-estimated model) of −0.23 ± 3.33 METs, indicating a slight advantage over wrist-worn consumer devices (Garmin: −0.64 ± 3.53 METs and Fitbit: −0.67 ± 3.40 METs). Class-know models reveal a comparable performance between Audéo (−0.21 ± 2.51 METs) and ZurichMove (−0.13 ± 2.49 METs). Sub-analyses show substantial variability in accuracy for different activities and good accuracy when activities are averaged over a typical day’s usage of 10 h (+61 ± 302 kcal). Discussion: This study shows the potential of hearing aid-integrated accelerometers in accurately estimating EE across a wide range of activities in the target demographic, while also highlighting the necessity for ongoing optimization efforts considering precision limitations observed across both consumer and research devices. [ABSTRACT FROM AUTHOR]

Introduction: There is limited information about the relationship between physical activity (PA) and sedentary behaviors in chronic kidney disease (CKD). Therefore, this study aims to explore the associations of accelerometermeasured PA and sedentary behaviors with CKD. Methods: A cross-sectional study was conducted using data from the National Health and Nutrition Examination Survey in the 2003–2004 and 2005–2006 survey cycles. A uniaxial accelerometer measured physical activity (PA) and sedentary time (ST). The associations of PA and ST with estimated glomerular filtration rate (eGFR) and odds of CKD adopted the generalized linear regression, multivariable logistic regression, and isotemporal substitution models. Results: A total of 5,990 adults with 605 CKD patients were included in this study. Compared with the individuals in the first quartile group, participants in the fourth quartile of low-intensity physical activity (LIPA), moderate to vigorous physical activity (MVPA), and ST were associated with 52% (35%, 65%) and 42% (14%, 62%) lower odds of CKD and 64% (17%, 131%) higher odds of CKD, respectively. Substituting 30 min/day of ST with equivalent LIPA/MVPA contributed to risk reduction in CKD. Discussion: The findings suggest that increased LIPA and MVPA and reduced ST were associated with a lower risk of CKD and that replacing ST with LIPA may decrease the risk of CKD. [ABSTRACT FROM AUTHOR]