Оценка управляемости и наблюдаемости линейных автоматических систем методом переменных состояния

Abstract Background Approximately half of 7-year-old children do not meet physical activity (PA) recommendations. Interventions targeting primary school children’s afterschool discretionary time could increase PA. Teaching assistants (TAs) are a school resource and could be trained to deliver after-school PA programmes. Building on earlier work, this paper describes the protocol for a cluster randomised feasibility study of a teaching assistant-led after-school intervention aimed at increasing PA levels of year 4 and 5 children (8–10 years old). Methods Phase 1—pre-baseline: 12 schools will be recruited. In all schools, self-reported PA will be measured in all consenting year 3 and 4 children. In four schools, pupils will additionally wear a waist-worn Actigraph accelerometer for 7 days. Phase 2—baseline: schools will be randomised to one of two enhanced recruitment strategies being tested for children: (1) a club briefing and (2) the briefing plus a taster Action 3:30 session. Up to 30 children per school will be able to attend Action 3:30 sessions and will provide baseline data on height, weight, psychosocial variables and accelerometer-measured PA. Phase 3—intervention and follow-up: Schools randomised into intervention or control arm. Intervention schools (n = 6) will receive a 15-week after-school programme when children are in years 4 and 5, run by TAs who have attended a 25-h Action 3:30 training programme. Control schools (n = 6) will continue with normal practice. Follow-up measures will be a repeat of baseline measures at the end of the 15-week intervention. Phase 4—process evaluation: session attendance, perceived enjoyment and perceived exertion will be assessed during the intervention, as well as the economic impact on schools. Post-study qualitative assessments with TAs, school contacts and pupils will identify how the programme could be refined. Accelerometer-determined minutes of moderate-to-vigorous physical activity (MVPA) per day will be calculated as this is likely to be the primary outcome in a future definitive trial. Discussion The Action 3:30 cluster randomised feasibility trial will assess the public health potential of this intervention approach and provide the information necessary to progress to a definitive cluster randomised controlled trial. Trial registration ISRCTN34001941 . Registered 01/12/2016

Considerations for Individual-Level Versus Whole-School Physical Activity Interventions:Stakeholder Perspectives

Strategies to address declining physical activity levels among children and adolescents have focused on ‘individual-level’ approaches which often fail to demonstrate impact. Recent attention has been on an alternative ‘whole-school’ approach to increasing physical activity that involves promoting physical activity throughout all aspects of the school environment. There is, however, a lack of evidence on how whole-school physical activity approaches could be implemented in the UK. This qualitative study explored perspectives of key stakeholders on potential reasons for the lack of impact of individual-level school-based interventions on children’s physical activity, and key considerations for adopting a whole-school approach. Nineteen semi-structured interviews were conducted with a range of stakeholders involved in the implementation of physical activity programmes in UK schools. Data were analysed using an inductive approach. Respondents suggested that individual-level school-based interventions to increase physical activity often failed to consult end users in the design and were typically implemented in environments unsupportive of long-term change. They subsequently outlined specific barriers and key facilitators for the adoption and implementation of whole-school approaches in UK settings and recommended a shift in research foci towards building an evidence base around educational outcomes and whole-school implementation insights

Physical activity and psychosocial characteristics of the peer supporters in the PLAN-A study – a latent class analysis

PLAN-A is a cluster randomised controlled trial of a peer-led physical activity intervention which uses peer supporters to increase the physical activity of 13–14-year-old girls in the UK. This paper uses latent class analysis to identify classes in the whole study population and investigate how those selected as peer supporters in PLAN-A were drawn from different social groups. We identified five classes of girls, based on psychosocial variables (self-esteem, physical activity self-efficacy, motivation, physical activity values among friends and peer support for physical activity (PA) and physical activity behaviour variables (average minutes of weekday MVPA, sedentary time and screen viewing). Peer supporters were similar to the whole study population in terms of overall demographics, but were drawn unequally from the five classes. In addition, there was considerable variation in the distribution of peer supporters between schools. The selection of peer supporters is an integral component of peer-led interventions and should be explored and linked to underlying theory to understand the characteristics of those recruited. However, demographic representativeness is not necessarily the aim, and simple reporting of overall demographic comparisons may mask important differences within subgroups

Action 3:30R: Results of a cluster randomised feasibility study of a revised teaching assistant-led extracurricular physical activity intervention for 8 to 10 year olds

Many children are not sufficiently physically active. We conducted a cluster-randomised feasibility trial of a revised after-school physical activity (PA) programme delivered by trained teaching assistants (TAs) to assess the potential evidence of promise for increasing moderate-to-vigorous physical activity (MVPA). Participants (n = 335) aged 8–10 years were recruited from 12 primary schools in South West England. Six schools were randomised to receive the intervention and six acted as non-intervention controls. In intervention schools, TAs were trained to deliver an after-school programme for 15 weeks. The difference in mean accelerometer-assessed MVPA between intervention and control schools was assessed at follow-up (T1). The cost of programme delivery was estimated. Two schools did not deliver the intervention, meaning four intervention and six control schools were analysed at T1. There was no evidence for a difference in MVPA at T1 between intervention and control groups. Programme delivery cost was estimated at £2.06 per pupil per session. Existing provision in the 12 schools cost £5.91 per pupil per session. Action 3:30 was feasible to deliver and considerably cheaper than existing after-school provision. No difference in weekday MVPA was observed at T1 between the two groups, thus progression to a full trial is not warranted

A revised teaching assistant-led extracurricular physical activity programme for 8- to 10-year-olds: The Action 3:30R feasibility cluster RCT

Abstract BackgroundMany children do not meet the recommended guidelines for physical activity (PA). The after-school period may be a critical time for children to participate in PA. Teaching assistants are important within the school system and could be trained to deliver after-school PA programmes. Our previous work showed promise for a teaching assistant-led after-school PA intervention. Objectives To examine the feasibility, evidence of promise and cost of Action 3:30R, a revised after-school PA intervention.DesignA cluster-randomised feasibility study, including process and economic evaluations.SettingTwelve primary schools in Southwest England. ParticipantsYear 4 and 5 children (8 to 10 years old).InterventionTwo teaching assistantss from each intervention school attended a 25-hour (five day) training course focused on how to deliver an after-school PA programme. As Action 3:30 is grounded in Self-Determination Theory, the training focussed on promoting children’s autonomy, belonging and competence. Teaching assistants received resources to aid delivery of a 60-minute after-school PA programme twice per week for 15 weeks (30 sessions). Main outcome measuresMeasures focused on feasibility outcomes and evidence of promise. Feasibility measures included recruitment of schools and pupils and attendance of the after-school programme. Evidence of promise was measured by comparison of accelerometer-determined minutes of moderate to vigorous PA between arms at follow up. Process evaluation measures were conducted using the RE-AIM framework. The cost of delivery was also assessed.ResultsTwelve primary schools were recruited.. 41% of eligible pupils consented, 49% of which were girls. Schools were randomised after baseline measures; six intervention (n=170 pupils) and six control (n=165 pupils). Two schools allocated to the intervention arm withdrew from the study before the start of the intervention leaving n=111 pupils in the intervention group. Intervention training was well attended and positively received; 8 of 9 teaching assistants attended 100% of sessions. Action 3:30R clubs were well attended; 74% of pupils attended at least 50% of the 30 sessions. Mean weekday moderate to vigorous PA did not differ between arms at T1 (-0.5, 95% CI = -4.57, 3.57). The process evaluation revealed Action 3:30R was received positively by pupils, teaching assistants and key contacts in intervention schools. Pupils enjoyed Action 3:30R and teaching assistants and pupils perceived the teaching style to be autonomy-supportive. Economic evaluation showed that Action 3:30R is inexpensive; the estimated cost of the programme after one year was £1.64 per pupil per session. Limitations Reason for withdrawal was given by one school but not the other. The reason given was inability to release staff for training. ConclusionsAction 3:30R is a low-cost, feasible after-school programme which engages a range of pupils and offers continuous professional development to teaching assistants. However, Action 3:30R does not show evidence of promise to increase levels of moderate to vigorous PA and does not warrant a trial evaluation.Future workFuture research should focus on improving the quality of current after-school provision in primary schools to increase PA

Effectiveness and cost-effectiveness of the PLAN-A intervention, a peer led physical activity program for adolescent girls:Results of a cluster randomised controlled trial

Background Physical activity is associated with improved health. Girls are less active than boys. Pilot work showed that a peer-led physical activity intervention called PLAN-A was a promising method of increasing physical activity in secondary school age girls. This study examined the effectiveness and cost-effectiveness of the PLAN-A intervention. Methods We conducted a cluster randomised controlled trial with Year 9 (13–14 year old) girls recruited from 20 secondary schools. Schools were randomly assigned to the PLAN-A intervention or a non-intervention control group after baseline data collection. Girls nominated students to be peer leaders. The top 18 % of girls nominated by their peers in intervention schools received three days of training designed to prepare them to support physical activity. Data were collected at two time points, baseline (T0) and 5–6 months post-intervention (T1). Participants wore an accelerometer for seven days to assess the primary outcome of mean weekday minutes of moderate-to-vigorous physical activity (MVPA). Multivariable mixed effects linear regression was used to estimate differences in the primary outcome between the two arms on an Intention-to-Treat (ITT) basis. Resource use and quality of life were measured and a within trial economic evaluation from a public sector perspective was conducted. Results A total of 1558 girls were recruited to the study. At T0, girls in both arms engaged in an average of 51 min of MVPA per weekday. The adjusted mean difference in weekday MVPA at T1 was − 2.84 min per day (95 % CI = -5.94 to 0.25) indicating a slightly larger decline in weekday MVPA in the intervention group. Results were broadly consistent when repeated using a multiple imputation approach and for pre-specified secondary outcomes and sub-groups. The mean cost of the PLAN-A intervention was £2817 per school, equivalent to £31 per girl. Economic analyses indicated that PLAN-A did not lead to demonstrable cost-effectiveness in terms of cost per unit change in QALY. Conclusions This study has shown that the PLAN-A intervention did not result in higher levels of weekday MVPA or associated secondary outcomes among Year 9 girls. The PLAN-A intervention should not be disseminated as a public health strategy