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Motor competence is important for lifelong physical activity (PA). The current study aimed to examine associations between PA and motor competence. In total, 43 children aged 7-12 years with intellectual disabilities and/or autism spectrum disorder completed anthropometric measures, the Bruininks-Oseretsky Test of Motor Proficiency-2, and wore a wrist accelerometer to capture total PA, moderate-to-vigorous PA (MVPA), average acceleration, and intensity gradient. No significant associations were found between PA outcomes and motor competence. Motor competence performance was commonly 'below average' or 'average'. The weakest subtests were upper limb coordination and strength. The strongest subtest was running speed and agility. Total weekly MVPA was 336.1 ± 150.3 min, higher than UK recommendations of 120-180 per week for disabled children and young people. Larger scale studies are needed to better understand the relationship between PA and motor competence. Future research should also consider the influence of environmental factors on PA in this group., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Little is known about the impact of an ecological dynamics (ED) intervention (EDI) on primary school children's physical literacy and well-being in the Hong Kong context. The aim of this project is to introduce a physical literacy and well-being framework through an EDI that allows primary school children to develop good physical activity (PA) and daily behavioural habits., Methods and Analysis: A four-arm (cluster) randomised controlled trial will be conducted to examine the effect of EDI on physical literacy and well-being in primary schools located in each of the 18 administrative districts of Hong Kong. Four classes in senior primary students (grade 4) at each school will be randomly assigned to the four different conditions. These participating schools will be equipped with sit-stand desks, PA recess facility and equipment, and sleep pillows. The research team will adopt both objective measures (aerobic fitness, fundamental movement skills, daily behaviour-physical activity and cognitive function) and self-reported measures (perceived physical literacy, quality of life, sleep quality) covering the elements and domains of physical literacy and well-being to examine the effects of EDIs at four time points, including baseline assessment, 3 months after intervention, postintervention and 3-month follow-up assessment. One-way analyses of variance (ANOVAs) will be used to test for differences in the baseline characteristics of participants between groups. Repeated measure ANOVAs and MANCOVA, with time (baseline, after intervention and follow-up) as within-subjects factor, and intervention group as between-subjects factors, will be used to evaluate the effects of different interventions on the students' physical literacy and well-being. A Bonferonni correction to the p value will be calculated to adjust for multiple tests., Ethics and Dissemination: Ethical approval was sought from the Joint CUHK-NTEC Clinical Research Ethics Committee in Hong Kong (CREC Ref.No.:2024.027). The finding of this study will be disseminated via peer-reviewed journals, international conference presentations and academic lectures. For secondary analysis of the data, please contact the corresponding author for permission., Trial Registration Number: ISRCTN84025914., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

We examined the compositional associations between the intensity spectrum derived from incremental acceleration intensity bands and the body mass index (BMI) z-score in youth, and investigated the estimated differences in BMI z-score following time reallocations between intensity bands. School-aged youth from 63 schools wore wrist accelerometers, and data of 1453 participants (57.5% girls) were analysed. Nine acceleration intensity bands (range: 0−50 mg to ≥700 mg) were used to generate time-use compositions. Multivariate regression assessed the associations between intensity band compositions and BMI z-scores. Compositional isotemporal substitution estimated the differences in BMI z-score following time reallocations between intensity bands. The ≥700 mg intensity bandwas strongly and inversely associated with BMI z-score (p < 0.001). The estimated differences in BMI z-score when 5 min were reallocated to and from the ≥700 mg band and reallocated equally among the remaining bands were −0.28 and 0.44, respectively (boys), and −0.39 and 1.06, respectively (girls). The time in the ≥700 mg intensity band was significantly associated with BMI z-score, irrespective of sex. When even modest durations of time in this band were reallocated, the asymmetrical estimated differences in BMI z-score were clinically meaningful. The findings highlight the utility of the full physical activity intensity spectrum over a priori-determined absolute intensity cut-point approaches.

This study validated sedentary behaviour (SB), moderate-to-vigorous physical activity (MVPA) and vigorous physical activity (VPA) accelerometer cut-points in 5-7-year-old children. Participants (n = 49, 55% girls) wore an ActiGraph GT9X accelerometer, recording data at 100 Hz downloaded in 1 s epochs, on both wrists and the right hip during a standardised protocol and recess. Cut-points were generated using ROC analysis with direct observation as a criterion. Subsequently, cut-points were optimised using Confidence intervals equivalency analysis and then cross-validated in a cross-validation group. SB cut-points were 36 mg (Sensitivity (Sn) = 79.8%, Specificity (Sp) = 56.8%) for non-dominant wrist, 39 mg (Sn = 75.4%, Sp = 70.2%) for dominant wrist and 20 mg (Sn = 78%, Sp = 50.1%) for hip. MVPA cut-points were 189 mg (Sn = 82.6%, Sp = 78%) for non-dominant wrist, 181 mg (Sn = 79.1%, Sp = 76%) for dominant wrist and 95 mg (Sn = 79.3%, Sp = 75.6%) for hip. VPA cut-points were 536 mg (Sn = 75.1%, Sp = 68.7%) for non-dominant wrist, 534 mg (Sn = 67.6%, Sp = 95.6%) for dominant wrist and 325 mg (Sn = 78.2%, Sp = 96.1%) for hip. All placements demonstrated adequate levels of accuracy for SB and PA assessment.