39 research outputs found

    Raw Acceleration from Wrist- and Hip-Worn Accelerometers Corresponds with Mechanical Loading in Children and Adolescents

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    This is the final version. Available on open access from MDPI via the DOI in this recordData Availability Statement: The data presented in this study are available on request from the corresponding author.The purpose of this study was to investigate associations between peak magnitudes of raw acceleration (g) from wrist- and hip-worn accelerometers and ground reaction force (GRF) variables in a large sample of children and adolescents. A total of 269 participants (127 boys, 142 girls; age: 12.3 ± 2.0 yr) performed walking, running, jumping (5 cm) and single-leg hopping on a force plate. A GENEActiv accelerometer was worn on the left wrist, and an Actigraph GT3X+ was worn on the right wrist and hip throughout. Mixed-effects linear regression was used to assess the relationships between peak magnitudes of raw acceleration and loading. Raw acceleration from both wrist and hip-worn accelerometers was strongly and significantly associated with loading (all p’s < 0.05). Body mass and maturity status (pre/post-PHV) were also significantly associated with loading, whereas age, sex and height were not identified as significant predictors. The final models for the GENEActiv wrist, Actigraph wrist and Actigraph hip explained 81.1%, 81.9% and 79.9% of the variation in loading, respectively. This study demonstrates that wrist- and hip-worn accelerometers that output raw acceleration are appropriate for use to monitor the loading exerted on the skeleton and are able to detect short bursts of high-intensity activity that are pertinent to bone health.Economic and Social Research Council (ESRC

    Associations between device-measured physical activity and performance-based physical function outcomes in adults: a systematic review and meta-analysis

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    This is the final version. Available on open access from BMJ Publishing Group via the DOI in this recordThis systematic review and meta-analysis aimed to examine the association between device-measured physical activity (PA) and performance-based measures of physical function (PF). Databases searched included CINAHL, Embase, MEDLINE/PubMed, SPORTDiscus, and Web of Science (last search conducted on November 11, 2022). Observational studies (cross-sectional or prospective) reporting associations between wearable device-measured PA and PF outcomes in non-clinical adults were eligible. Forty-two studies with a pooled sample of 27 276 participants were eligible, with 34 studies reporting a standardised regression coefficient (β) between at least one of four PA measures and one of six PF outcomes. All measures of PA were positively associated with all measures of PF, except for step count with grip strength. Largest associations were seen with lower-body PF tests; gait speed (βs=0.11–0.26), walk tests (βs=0.18–0.41), chair-rise test (βs=0.10–0.26), balance (βs=0.07–0.24) and Timed Up-and-Go (βs=0.10–0.24) all p<0.01. Small or no association was seen with grip strength (βs=0.02–0.07). In observational studies of general adult populations, there were associations between multiple dimensions of PA and a broad range of PF measures. The findings provide provisional support for the use of device measures of movement to remotely monitor people for risk of low PF. Prospective designs are needed to determine the direction of the relationship. Future studies should also explore a broader range of PA metrics beyond simple aggregate measures of time spent at different acceleration values as there is evidence that the temporal distribution of activity is related to health and functional outcomes.Economic and Social Research Council (ESRC

    Improving the identification of bone‐specific physical activity using wrist‐worn accelerometry: A cross‐sectional study in 11–12‐year‐old Australian children

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    This is the final version. Available from Wiley via the DOI in this record. DATA AVAILABILITY STATEMENT: The LSAC and CheckPoint data are available under license at https:// growingupinaustralia.gov.au/data‐and‐documentation/accessing‐lsac ‐data. To access raw accelerometry data, please contact the MCRI's LifeCourse initiative https://lifecourse.melbournechildrens.comPhysical activity (PA) during childhood and adolescence is important for the accrual of maximal peak bone mass. The precise dose that benefits bone remains unclear as methods commonly used to analyze PA data are unsuitable for measuring bone‐ relevant PA. Using improved accelerometry methods, this study identified the amount and intensity of PA most strongly associated with bone outcomes in 11–12‐ year‐olds. Participants (n = 770; 382 boys) underwent tibial peripheral quantitative computed tomography to assess trabecular and cortical density, endosteal and periosteal circumference and polar stress‐strain index. Seven‐day wrist‐worn raw acceleration data averaged over 1‐s epochs was used to estimate time accumulated above incremental PA intensities (50 milli‐gravitational unit (mg) increments from 200 to 3000 mg). Associations between time spent above each 50 mg increment and bone outcomes were assessed using multiple linear regression, adjusted for age, sex, height, weight, maturity, socioeconomic position, muscle cross‐sectional area and PA below the intensity of interest. There was a gradual increase in mean R2 change across all bone‐related outcomes as the intensity increased in 50 mg increments from >200 to >700 mg. All outcomes became significant at >700 mg (R2 change = 0.6%–1.3% and p = 0.001–0.02). Any further increases in intensity led to a reduction in mean R2 change and associations became non‐significant for all outcomes >1500 mg. Using more appropriate accelerometry methods (1‐s epochs; no a priori application of traditional cut‐points) enabled us to identify that ~10 min/day of PA >700 mg (equivalent to running ~10 km/h) was positively associated with pQCT‐derived measures of bone density, geometry and strength in 11–12‐year‐ olds.Australian National Health and Medical Research CouncilAustralian National Health and Medical Research CouncilRoyal Children's Hospital FoundationNIHR Leicester Biomedical Research CentreVictorian Deaf Education InstituteEconomic and Social Research CouncilUniversity of MelbourneNational Heart Foundation of AustraliaCollaboration for Leadership in Applied Health Research and Care East MidlandsFinancial Markets Foundation for ChildrenFinancial Markets Foundation for ChildrenNHMCR Principal Research FellowshipMurdoch Children's Research Institut

    Development and application of accelerometry methods to precisely quantify physical activity relevant to bone health in children and adolescents

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    Physical activity (PA) during childhood and adolescence is important for the accrual of maximal peak bone mass, which helps to reduce the risk of fracture in later life. However, the dose of PA (amount, type, frequency, intensity) required to benefit bone remains unclear. This is likely due, in part, to a lack of standardised, comparable methods for assessing PA and development of methods that better target the measurements of bone-specific characteristics of PA in free-living populations. Accelerometers are frequently used to assess PA in free-living situations, however, common accelerometry methods are unsuitable for measuring short bursts of high-impact activity most relevant to bone. The thesis therefore aimed to develop and use accelerometry methods that more precisely quantify bone-relevant PA in children and adolescents. A systematic review of the accelerometry methods used in studies assessing associations between habitual PA and bone in children and adolescents was conducted (chapter 3). This demonstrated that the methods used varied widely between studies and the use of long epochs and cardiovascular-based intensity cut-points suggest that updated, bone-specific methods are needed. The next study (chapter 4) demonstrated that it was possible to adapt existing accelerometry methods (using 1-second epochs and smaller intensity increments) to identify a bone-specific PA intensity in a population-based sample of 11-12-year-olds. However, whilst these methods overcome some of the methodological limitations identified and will help to further understanding of the influence of PA on bone, it is likely that methods that use the raw acceleration signal (without an epoch), which has the resolution to identify detailed aspects of PA, (e.g., magnitude and number of impacts/loading) are needed in the future. Whilst more work is required before metrics directly derived from raw acceleration can be used in free-living situations, the final study in the thesis (chapter 5) demonstrated that peak magnitudes of raw acceleration from both wrist- and hip-worn monitors reflects the loading incurred during PA in this population and is therefore a suitable proxy measure of loading that can be applied to free-living situations in the future. The overall message in this thesis is that in order to establish the precise dose-response relationship between PA and bone, a shift in the approach to measuring bone-relevant activity is needed

    Prepare for Retirement

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    A comparison of the associations between bone health and three different intensities of accelerometer-derived habitual physical activity in children and adolescents: a systematic review

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    This is the final version. Available on open access from Springer via the DOI in this recordAvailability of data and material: The research data supporting this publication are provided within this paper.Purpose Positive associations have been identified between bone outcomes and accelerometer-derived moderate (MPA) and vigorous (VPA) physical activity (PA) in youth, however, it remains unclear which intensity is most beneficial. This systematic review aimed to summarise accelerometer-derived methods used to estimate habitual PA in children and adolescents and determine whether the magnitude of association was consistently stronger for a particular intensity (MPA/MVPA/VPA). Methods Observational studies assessing associations between accelerometer-derived MPA and/or MVPA and VPA with bone outcomes in children and adolescents (≤ 18 years) were identified in MEDLINE, EMBASE, Web of Science, SPORTDiscus and the Cochrane Central Register of Controlled Trials. Thirty articles were included (total n=20,613 (10,077 males), 4- 18 years). Chi-square tests determined whether the proportion of significant associations and strongest within-study associations, differed significantly between intensities. Results Accelerometer methods were highly variable between studies. Of the 570 associations analysed, 186 were significant (p<0.05). The proportion of within-study strongest associations differed by PA intensity (3x2 χ 2=86.6, p<0.001) and was significantly higher for VPA (39%) compared to MVPA (5%; 2x2 χ 2=55.3, p<0.001) and MPA (9%, 2x2 χ 2=49.1, p<0.001). Conclusion Results indicated a greater benefit of VPA over MPA/MVPA, however, variability in accelerometer-derived methods used prevents the precise bone-benefitting amount of VPA from being identified. Long epochs and numerous intensity cut-point definitions mean that bone-relevant PA has likely been missed or misclassified in this population. Future research should explore the use of shorter epochs (1s) and identify bone-specific activity intensities, rather than using pre-defined activity classifications more relevant to cardiovascular health.Economic and Social Research Council (ESRC

    A Microphthalmic Family

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