Dr Angus Leahy

Introduction: The relationship between physical activity (PA) intensity and executive functions in older adolescents remains poorly understood. This study aimed to examine the associations between PA intensity, volume, attentional control, and working memory and the moderating effects of sex in older adolescents. Method: We analyzed baseline data from 418 participants (211 females, Mage¿=¿16.5 ± 0.40 years) from the Burn 2 Learn trial. Adolescents wore GT9X Link accelerometers on a non-dominant wrist for 7 days, 24-h·d-1. PA intensity was expressed as intensity gradient (IG) and moderate-to-vigorous PA (MVPA, Hildebrand cut-points); PA volume was expressed as average acceleration (AvACC). Attentional control was measured with a standard deviation (SDRT) and a coefficient of variation (CVRT) of the reaction time on the incongruent trials of a flanker task. Working memory was expressed as a d prime (a signal discrimination index) on the 2-back task. The moderating effects of sex on the PA-executive functions associations, adjusting for age, BMI z-score, and cardiorespiratory fitness, were tested using multilevel random intercept models. Results: After controlling for AvACC, sex moderated the relationships between IG and incongruent SDRT (B¿=¿0.53, 95% CI: 0.12, 0.94) and CVRT (B¿=¿0.63, 95% CI: 0.22, 1.05; ps = 0.002). Only girls with higher IG showed smaller incongruent SDRT and CVRT (Bs = -0.26, ps = 0.01). IG was not related to working memory. AvACC and MVPA were not associated with attentional control or working memory. Conclusion: Our findings reveal a novel association between higher-intensity PA and superior attentional control among adolescent girls.

The aim of our systematic review and meta-analysis was to quantitatively synthesise the effects of school-based peer-led interventions on leaders' academic, psychosocial, behavioural, and physical outcomes. Eligible studies were those that: (i) evaluated a school-based peer-led intervention using an experimental or quasi-experimental study design, (ii) included an age-matched control or comparison group, and (iii) evaluated the impact of the intervention on one or more leader outcomes. Medline, Sportdiscus, Psychinfo, Embase, and Scopus online databases were searched on the 24th of October, 2022 which yielded 13,572 results, with 31 included in the narrative synthesis and 12 in the meta-analysis. We found large positive effects for leaders' attitudes toward bullying (d = 1.02), small-to-medium positive effects for leaders' literacy (d = 0.39), and small positive effects for leaders' self-esteem (d = 0.18). There were mixed findings for behavioural outcomes and null effects for physical outcomes. Notable limitations of this research are the inclusion of a relatively small number of studies, and high heterogeneity in those included. Our findings have the potential to inform educational practice, but also highlight the need for further research examining the mechanisms that might account for the observed effects. Our systematic review was prospectively registered with PROSPERO (CRD42021273129).

Background: Adolescents with disability are less active and have lower levels of physical fitness than their typically developing peers. Schools are ideal settings to address this; however, few school-based interventions have been designed and evaluated among this group. Therefore, the aim of this pilot study was to determine the feasibility of a time-efficient school-based physical activity intervention for adolescents with disability. Methods: A non-randomized pilot trial was conducted with adolescents in the special education unit at one secondary school in New South Wales, Australia. Sixteen grade 11 and 12 students (aged 17.3 ± 0.7 years) participated in the 2-month physical activity intervention. Two classroom teachers were trained to facilitate the delivery of a high-intensity interval training (HIIT) program, known as Burn 2 Learn adapted (B2La). Teachers were asked to deliver 2¿3 weekly HIIT sessions for a period of 2 months. Four domains of feasibility (acceptability, implementation, adaptability, and practicality) were assessed using quantitative measures at the student and teacher levels (e.g., observations, process evaluation questionnaires, and heart rate [HR] monitoring). Data were also collected from three learning and support teachers who assisted classroom teachers with intervention delivery. Preliminary efficacy of the intervention on measures of adolescents' functional capacity (6-min walk/run test) and muscular fitness (sit-to-stand test and modified push-up test) were analyzed using paired sample t-tests. Results: Moderate-to-high levels of program satisfaction were reported by both students (80% rated "Good" or "Excellent") and teachers (100% rated "Good" or "Excellent"). Teachers reported delivering 2.5 ± 0.7 sessions per week during the study. Based on researcher session observations, the program was delivered effectively by teachers (14/20). However, HR data indicated session intensity was lower than intended. The program was considered "adaptable" by teachers, with several observed modifications to HIIT sessions to cater for the needs of adolescents with disability. No adverse events were reported. We observed improvements in preliminary efficacy measures. Conclusions: Our findings suggest it is feasible to train teachers to deliver a school-based HIIT program for adolescents with disability. Evaluation of B2La within a larger-scale effectiveness trial is warranted. Trial registration: ACTRN12621000219886.

Background Cardiorespiratory fitness (CRF) is an important marker of current and future health status. The primary aim of our study was to evaluate the impact of a time-efficient school-based intervention on older adolescents' CRF. Methods Two-arm cluster randomised controlled trial conducted in two cohorts (February 2018 to February 2019 and February 2019 to February 2020) in New South Wales, Australia. Participants (N=670, 44.6% women, 16.0±0.43 years) from 20 secondary schools: 10 schools (337 participants) were randomised to the Burn 2 Learn (B2L) intervention and 10 schools (333 participants) to the control. Teachers in schools allocated to the B2L intervention were provided with training, resources, and support to facilitate the delivery of high-intensity interval training (HIIT) activity breaks during curriculum time. Teachers and students in the control group continued their usual practice. The primary outcome was CRF (20 m multi-stage fitness test). Secondary outcomes were muscular fitness, physical activity, hair cortisol concentrations, mental health and cognitive function. Outcomes were assessed at baseline, 6 months (primary end-point) and 12 months. Effects were estimated using mixed models accounting for clustering. Results We observed a group-by-time effect for CRF (difference=4.1 laps, 95% CI 1.8 to 6.4) at the primary end-point (6 months), but not at 12 months. At 6 months, group-by-time effects were found for muscular fitness, steps during school hours and cortisol. Conclusions Implementing HIIT during curricular time improved adolescents' CRF and several secondary outcomes. Our findings suggest B2L is unlikely to be an effective approach unless teachers embed sessions within the school day. Trial registration number Australian New Zealand Clinical Trials Registry (ACTRN12618000293268).

Background: Participation in physical activity supports greater cardiorespiratory fitness (CRF), a correlate of cognitive control. However, the relationship between muscular fitness (MF) and cognitive control is less clear. The present study investigated the differential relationship of CRF and MF with cognitive control in older adolescents. Methods: This cross-sectional study involved students (15¿17 years old, n = 541, 43% female) from 20 secondary schools who completed tests of inhibition (modified flanker task), working memory (n-back task), CRF (Progressive Aerobic Cardiovascular Endurance Run), and MF (standing long jump and push-up test). Multilevel analyses tested the association between CRF or MF and cognitive outcomes while accounting for the influence of the other fitness variable and relevant demographic factors. Results: CRF predicted response accuracy during incongruent flanker trials, the condition requiring greater inhibition. For the working memory task, CRF predicted greater target accuracy and greater d' scores on the 1-back task, requiring lesser amounts of working memory. In the 2-back task, which requires greater amounts of working memory, CRF also predicted greater target and non-target accuracy and d' scores. Comparatively, MF did not predict any cognitive outcomes after adjustment for CRF. Conclusion: CRF was selectively related to better performance during task conditions that require greater amounts of inhibition and working memory. This finding suggests that CRF, but not MF, may benefit cognitive control in older adolescents. This selective influence of CRF on older adolescents' cognition highlights the value of aerobic physical activity.

The feasibility requirements of administering field-based cognitive assessments are rarely reported. We examined the feasibility of administering a group-based cognitive test battery in a school setting with older adolescents. Several types of reliability were also assessed in the control group. Preliminary efficacy and the relationship between changes in fitness and changes in cognitive control were also explored following a 14-week HIIT intervention (3 sessions/week). Participants completed a cognitive test battery measuring inhibition (flanker), and working memory (n-back) at baseline and post-test.¿Health-related fitness assessments were also conducted.¿Test administration took approximately 30.8¿±¿1.5¿minutes to complete with up to six participants simultaneously. The test battery demonstrated acceptable reliability (ICC¿=¿0.5¿0.81), with significant changes observed for flanker incongruent accuracy, and 2-back non-target accuracy from baseline to post-test. Regarding efficacy,¿small-to-moderate effects were observed for accuracy outcomes, while several small associations were found between changes in fitness and changes in cognition. Findings from the current study suggest a cognitive test battery can be administered with older adolescents in a school setting. However, there remains a lack of adequate reporting of administration requirements for field-based cognitive assessments. Efficacy findings should be confirmed with a larger and more representative sample of older adolescents.