Effectiveness and cost-effectiveness of the GoActive intervention to increase physical activity among UK adolescents: A cluster randomised controlled trial.

BACKGROUND: Less than 20% of adolescents globally meet recommended levels of physical activity, and not meeting these recommended levels is associated with social disadvantage and rising disease risk. The determinants of physical activity in adolescents are multilevel and poorly understood, but the school's social environment likely plays an important role. We conducted a cluster randomised controlled trial to assess the effectiveness of a school-based programme (GoActive) to increase moderate-to-vigorous physical activity (MVPA) among adolescents. METHODS AND FINDINGS: Non-fee-paying, co-educational schools including Year 9 students in the UK counties of Cambridgeshire and Essex were eligible for inclusion. Within participating schools (n = 16), all Year 9 students were eligible and invited to participate. Participants were 2,862 13- to 14-year-olds (84% of eligible students). After baseline assessment, schools were computer-randomised, stratified by school-level pupil premium funding (below/above county-specific median) and county (control: 8 schools, 1,319 participants, mean [SD] participants per school n = 165 [62]; intervention: 8 schools, 1,543 participants, n = 193 [43]). Measurement staff were blinded to allocation. The iteratively developed, feasibility-tested 12-week intervention, aligned with self-determination theory, trained older adolescent mentors and in-class peer-leaders to encourage classes to conduct 2 new weekly activities. Students and classes gained points and rewards for engaging in any activity in or out of school. The primary outcome was average daily minutes of accelerometer-assessed MVPA at 10-month follow-up; a mixed-methods process evaluation evaluated implementation. Of 2,862 recruited participants (52.1% male), 2,167 (76%) attended 10-month follow-up measurements; we analysed the primary outcome for 1,874 participants (65.5%). At 10 months, there was a mean (SD) decrease in MVPA of 8.3 (19.3) minutes in the control group and 10.4 (22.7) minutes in the intervention group (baseline-adjusted difference [95% confidence interval] -1.91 minutes [-5.53 to 1.70], p = 0.316). The programme cost £13 per student compared with control; it was not cost-effective. Overall, 62.9% of students and 87.3% of mentors reported that GoActive was fun. Teachers and mentors commented that their roles in programme delivery were unclear. Implementation fidelity was low. The main methodological limitation of this study was the relatively affluent and ethnically homogeneous sample. CONCLUSIONS: In this study, we observed that a rigorously developed school-based intervention was no more effective than standard school practice at preventing declines in adolescent physical activity. Interdisciplinary research is required to understand educational-setting-specific implementation challenges. School leaders and authorities should be realistic about expectations of the effect of school-based physical activity promotion strategies implemented at scale. TRIAL REGISTRATION: ISRCTN Registry ISRCTN31583496.

General practitioners' attitudes and decision making regarding admission for older adults with infection: a UK qualitative interview study.

BACKGROUND: The world has an ageing population. Infection is common in older adults; serious infection has a high mortality rate and is associated with unplanned admissions. In the UK, general practitioners (GPs) must identify which older patients require admission to hospital and provide appropriate care and support for those staying at home. OBJECTIVES: To explore attitudes of UK GPs towards referring older patients with suspected infection to hospital, how they weigh up the decision to admit against the alternatives and how alternatives to admission could be made more effective.Methods. Qualitative study using semi-structured interviews. GPs were purposively sampled from across the UK to achieve maximum variation in terms of GP role, experience and practice population. Interview transcripts were coded and analysed using a modified framework approach. RESULTS: GPs' key influences on decision making were grouped into patient, GP and system factors. Patient factors included clinical factors, social factors and shared decision making. GP factors included gut instinct, risk management and acknowledging an associated personal emotional burden. System factors involved weighing up the pressure on secondary care beds against increasing GP workload. GPs described that finding an alternative to admission could be more time consuming, complex to arrange or were restricted by lack of capacity. CONCLUSION: GPs need to be empowered to make safe decisions about place of care for older adults with suspected infection. This may mean developing strategies to support decision making as well as improving the ease of access to, and capacity of, any alternatives to admission.

Challenges and strategies for general practitioners diagnosing serious infections in older adults: a UK qualitative interview study.

BACKGROUND: Serious infections in older people are associated with unplanned hospital admissions and high mortality. Recognising the presence of a serious infection and making an accurate diagnosis are important challenges for General Practice. This study aimed to explore the issues UK GPs face when diagnosing serious infections in older patients. METHODS: Qualitative study using semi-structured interviews. 28 GPs from 27 practices were purposively sampled from across the UK to achieve maximum variation in terms of GP role, experience and practice population. Interviews began by asking participants to describe recent or memorable cases where they had assessed older patients with suspected serious infections. Additional questions from the topic guide were used to explore the challenges further. Interview transcripts were coded and analysed using a modified framework approach. RESULTS: Diagnosing serious infection in older adults was perceived to be challenging by participating GPs and the diagnosis was often uncertain. Contributing factors included patient complexity, atypical presentations, as well as a lack of knowledge of patients due to a loss in continuity. Diagnostic challenges were present at each stage of the patient assessment. Scoring systems were mainly used as communication tools. Investigations were sometimes used to resolve diagnostic uncertainty, but availability and speed of result limited their practical use. Clear safety-net plans shared with patients and their families helped GPs manage ongoing uncertainty. CONCLUSIONS: Diagnostic challenges are present throughout the assessment of an older adult with a serious infection in primary care. Supporting GPs to provide continuity of care may improve the recognition and developing point of care testing for use in community settings may reduce diagnostic uncertainty.

Helping parents know when to seek help for an acutely ill child: Evidence based co-development of a mobile phone app using complex intervention methodology.

BACKGROUND: Acute illness accounts for the majority of episodes of illness in children under five years of age and is the age group with the highest consultation rate in general practice in the UK. The number of children presenting to emergency care is also steadily increasing, having risen beyond pre-pandemic numbers. Such high, and increasing, rates of consultation have prompted concerns about parents' level of knowledge and confidence in caring for their children when they are ill, and particularly when and how to seek help appropriately. AIM: The ASK SNIFF collaboration research programme identified parents' need for accurate and accessible information to help them know when to seek help for a sick child in 2010. This paper presents the resulting programme of research which aimed to co-develop an evidence-based safety netting intervention (mobile app) to help parents know when to seek help for an acutely ill child under the age of five years in the UK. METHODS: Our programme used a collaborative six step process with 147 parent and 324 health professional participants over a period of six years including: scoping existing interventions, systematic review, qualitative research, video capture, content identification and development, consensus methodology, parent and expert clinical review. RESULTS: Our programme has produced evidence-based content for an app supported by video clips. Our collaborative approach has supported every stage of our work, ensuring that the end result reflects the experiences, perspectives and expressed needs of parents and the clinicians they consult. CONCLUSION: We have not found any other resource which has used this type of approach, which may explain why there is no published evaluation data demonstrating the impact of existing UK resources. Future mobile apps should be designed and developed with the service users for whom they are intended.

Experiences of urine collection devices during suspected urinary tract infections: a qualitative study in primary care.

BACKGROUND: Up to 30% of urine samples from women with suspected urinary tract infection (UTI) are contaminated and need to be repeated, burdening health services and delaying antibiotic prescription. To prevent contamination, midstream urine (MSU) sampling, which can be difficult to achieve, is recommended. Urine collection devices (UCDs) that automatically capture MSU have been proposed as a solution. There are few studies exploring women's experiences of using such devices. AIM: To explore women's experiences of urine collection and the use of UCDs during a suspected UTI. DESIGN AND SETTING: An embedded qualitative study in a UK randomised controlled trial (RCT) of UCDs among women attending primary care for UTI symptoms. METHOD: Semi-structured telephone interviews with 29 women who had participated in the RCT were conducted. The transcribed interviews were then thematically analysed. RESULTS: Most of the women were dissatisfied with how they normally produced urine samples. Many were able to use the devices, found them hygienic, and would use them again, even if they had initially experienced problems. Women who had not used the devices expressed interest in trying them. Potential barriers to UCD use included positioning for the sample, UTI symptoms making urine collection difficult, and waste disposal because of the single-use plastic in the UCDs. CONCLUSION: Most women agreed there was a need for a user- and environmentally-friendly device to improve urine collection. Although using UCDs can be difficult for women experiencing UTI symptoms, they may be appropriate for asymptomatic sampling in other clinical populations.

Women's information needs around urine testing for urinary tract infections: a qualitative study.

BACKGROUND: Urinary tract infection (UTI) is one of the commonest bacterial infections in general practice, with urine testing a frequent feature of its management. Urinary dipsticks are widely used, with urine culture the reference standard test. To avoid contamination, patients are advised to discard the first part of the urine stream, retaining the midstream part for the sample. This process, however, can be challenging both to explain and to perform. There is a lack of literature investigating women's perceptions and understanding of urine sampling. AIM: To explore women's understanding of urine collection, sample contamination, and how information from samples informed UTI management. DESIGN AND SETTING: Qualitative study embedded in a UK randomised controlled trial (RCT) of urinary collection devices (UCDs) among women attending primary care with a suspected UTI. METHOD: Semi-structured telephone interviews were conducted with 29 women participating in the RCT. Interviews were transcribed and thematically analysed. RESULTS: Participants were not always aware about what midstream samples were and why they were preferable. They also lacked understanding about how urine samples may be contaminated, and sources of contamination. Participants experienced variability in the information received following analysis of their sample. CONCLUSION: Provision of clear information could help provide better urine samples, aiding the diagnosis of UTIs, presenting results with greater clarity, and creating less need for repeat samples. Sharing of information derived from uncontaminated samples may also support better UTI management, helping to reduce unnecessary prescribing and antibiotic resistance.

Urine collection devices to reduce contamination in urine samples for diagnosis of uncomplicated UTI: a single-blind randomised controlled trial in primary care.

BACKGROUND: Urine collection devices (UCDs) are being marketed and used in clinical settings to reduce urine sample contamination, despite inadequate supporting evidence. AIM: To determine whether UCDs, compared with standardised instructions for urine sample collection, reduce the proportion of contaminated samples. DESIGN AND SETTING: Single-blind randomised controlled trial in general practices in England and Wales. METHOD: Women aged ≥18 years presenting with symptoms attributable to urinary tract infection (UTI) were randomised (1:1:1) to use either a Peezy UCD or a Whiz Midstream UCD, or were given standardised verbal instructions (SVI) for midstream sample collection. The primary outcome was the proportion of urine samples reported as contaminated by microbiology laboratory analysis. RESULTS: A total of 1264 women (Peezy UCD: n = 424; Whiz Midstream UCD: n = 421; SVI: n = 419) were randomised between October 2016 and August 2018. Ninety women were excluded from the primary analysis as a result of ineligibility or lack of primary outcome data, leaving 1174 (Peezy UCD: n = 381; Whiz Midstream UCD: n = 390; SVI: n = 403) for intention-to-treat analysis. The proportion of contaminated samples was 26.5% with the Peezy UCD, 28.2% with the Whiz Midstream UCD, and 29.0% with SVI (relative risk: Peezy UCD versus SVI = 0.91, 95% CI = 0.76 to 1.09, P = 0.32; Whiz Midstream UCD versus SVI = 0.98, 95% CI = 0.97 to 1.20, P = 0.82). There were 100 (25.3%) device failures with the Peezy UCD and 35 (8.8%) with the Whiz Midstream UCD; the proportion of contaminated samples was similar after device failure samples were excluded. CONCLUSION: Neither the Peezy UCD nor the Whiz Midstream UCD reduced urine sample contamination when used by women presenting to primary care with suspected UTI. Their use cannot be recommended for this purpose in this setting.

The school policy, social, and physical environment and change in adolescent physical activity: An exploratory analysis using the LASSO.

PURPOSE: We examined the association between the school policy, social and physical environment and change in adolescent physical activity (PA) and explored how sex and socioeconomic status modified potential associations. METHODS: Data from the GoActive study were used for these analyses. Participants were adolescents (n = 1765, mean age±SD 13.2±0.4y) from the East of England, UK. Change in longitudinal accelerometer assessed moderate-to-vigorous physical activity (MVPA) was the outcome. School policy, social and physical environment features (n = 267) were exposures. The least absolute shrinkage and selection operator variable selection method (LASSO) was used to determine exposures most relevant to the outcome. Exposures selected by the LASSO were added to a multiple linear regression model with estimates of change in min/day of MVPA per 1-unit change in each exposure reported. Post-hoc analyses, exploring associations between change in variables selected by the LASSO and change in MVPA, were undertaken to further explain findings. FINDINGS: No school policy or physical environment features were selected by the LASSO as predictors of change in MVPA. The LASSO selected two school social environment variables (participants asking a friend to do physical activity; friend asking a participant to do physical activity) as potential predictors of change in MVPA but no significant associations were found in subsequent linear regression models for all participants (ß [95%CI] -1.01 [-2.73;0.71] and 0.65 [-2.17;0.87] min/day respectively). In the post-hoc analyses, for every unit increase in change in participants asking a friend to do PA and change in a friend asking participants to do PA, an increase in MVPA of 2.78 (1.55;4.02) and 1.80 (0.48;3.11) min/day was predicted respectively. CONCLUSIONS: The school social environment is associated with PA during adolescence. Further exploration of how friendships during adolescence may be leveraged to support effective PA promotion in schools is warranted.

Adolescents' perspectives on a school-based physical activity intervention: A mixed method study.

Purpose: To examine adolescent experiences and perspectives of the GoActive intervention (ISRCTN31583496) using mixed methods process evaluation to determine satisfaction with intervention components and interpret adolescents' experiences of the intervention process in order to provide insights for future intervention design. Methods: Participants (n = 1542; 13.2 ±  0.4 years, mean ± SD) provided questionnaire data at baseline (shyness, activity level) and post-intervention (intervention acceptability, satisfaction with components). Between-group differences (boys vs. girls and shy/inactive vs. others) were tested with linear regression models, accounting for school clustering. Data from 16 individual interviews (shy/inactive) and 11 focus groups with 48 participants (mean = 4; range 2-7) were thematically coded. Qualitative and quantitative data were merged in an integrative mixed methods convergence matrix, which denoted convergence and dissonance across datasets. Results: Effect sizes for quantitative results were small and may not represent substantial between-group differences. Boys (vs. girls) preferred class-based sessions (ß = 0.2, 95% confidence interval (CI): 0.1-0.3); qualitative data suggested that this was because boys preferred competition, which was supported quantitatively (ß = 0.2, 95%CI: 0.1-0.3). Shy/inactive students did not enjoy the competition (ß = -0.3, 95%CI: -0.5 to -0.1). Boys enjoyed trying new activities more (ß = 0.1, 95%CI: 0.1-0.2); qualitative data indicated a desire to try new activities across all subgroups but identified barriers to choosing unfamiliar activities with self-imposed choice restriction leading to boredom. Qualitative data highlighted critique of mentorship; adolescents liked the idea, but older mentors did not meet expectations. Conclusion: We interpreted adolescent perspectives of intervention components and implementation to provide insights into future complex interventions aimed at increasing young people's physical activity in school-based settings. The intervention component mentorship was liked in principle, but implementation issues undesirably impacted satisfaction; competition was disliked by girls and shy/inactive students. The results highlight the importance of considering gender differences in preference of competition and extensive mentorship training.

Pre-analytical error for three point of care venous blood testing platforms in acute ambulatory settings: A mixed methods service evaluation.

INTRODUCTION: Point of care blood testing to aid diagnosis is becoming increasingly common in acute ambulatory settings and enables timely investigation of a range of diagnostic markers. However, this testing allows scope for errors in the pre-analytical phase, which depends on the operator handling and transferring specimens correctly. The extent and nature of these pre-analytical errors in clinical settings has not been widely reported. METHODS: We carried out a convergent parallel mixed-methods service evaluation to investigate pre-analytical errors leading to a machine error reports in a large acute hospital trust in the UK. The quantitative component comprised a retrospective analysis of all recorded error codes from Abbott Point of Care i-STAT 1, i-STAT Alinity and Abbott Rapid Diagnostics Afinion devices to summarise the error frequencies and reasons for error, focusing on those attributable to the operator. The qualitative component included a prospective ethnographic study and a secondary analysis of an existing ethnographic dataset, based in hospital-based ambulatory care and community ambulatory care respectively. RESULTS: The i-STAT had the highest usage (113,266 tests, January 2016-December 2018). As a percentage of all tests attempted, its device-recorded overall error rate was 6.8% (95% confidence interval 6.6% to 6.9%), and in the period when reliable data could be obtained, the operator-attributable error rate was 2.3% (2.2% to 2.4%). Staff identified that the most difficult step was the filling of cartridges, but that this could be improved through practice, with a perception that cartridge wastage through errors was rare. CONCLUSIONS: In the observed settings, the rate of errors attributable to operators of the primary point of care device was less than 1 in 40. In some cases, errors may lead to a small increase in resource use or time required so adequate staff training is necessary to prevent adverse impact on patient care.

Reach, Recruitment, Dose, and Intervention Fidelity of the GoActive School-Based Physical Activity Intervention in the UK: A Mixed-Methods Process Evaluation.

School-based multi-component physical activity (PA) promotion is advocated; however, research has indicated that a multi-component approach may not always be effective at increasing adolescent PA. Evaluation of the GoActive 12-week multi-component school-based intervention showed no effect on adolescent PA. A mixed-methods process evaluation was embedded to facilitate greater understanding of the results, to elicit subgroup perceptions, and to provide insight into contextual factors influencing intervention implementation. This paper presents the reach, recruitment, dose, and fidelity of GoActive, and identifies challenges to implementation. The process evaluation employed questionnaires (1543 Year 9s), individual interviews (16 Year 9s; 7 facilitators; 9 contact teachers), focus groups (48 Year 9s; 58 mentors), alongside GoActive website analytics and researcher observations. GoActive sessions reached 39.4% of Year 9s. Intervention satisfaction was relatively high for mentors (87.3%) and facilitators (85.7%), but lower for Year 9s (59.5%) and teachers (50%). Intervention fidelity was mixed within and between schools. Mentorship was the most implemented component. Factors potentially contributing to low implementation included ambiguity of the roles subgroups played within intervention delivery, Year 9 engagement, institutional support, and further school-level constraints. Multiple challenges and varying contextual considerations hindered the implementation of GoActive in multiple school sites. Methods to overcome contextual challenges to implementation warrant in-depth consideration and innovative approaches.

"She's gone now." A mixed methods analysis of the experiences and perceptions around the deaths of children who died unexpectedly in health care facilities in Cape Town, South Africa.

PURPOSE: The sudden death of a child is a catastrophic event for both the family and the healthcare workers involved. Confidential enquiries provide a biomedical depiction of the processes and quality of care delivered and drive improvements in care. However, these rarely include an assessment of the patient/caregiver experience which is increasingly regarded as a key measure of quality of care. METHODS: A parallel convergent mixed methods design was used to compare and contrast medically-assessed clinical quality of care with caregiver perceptions of quality and care in a cohort of sudden childhood deaths in emergency facilities in Cape Town, South Africa. RESULTS: Amongst the 29 sudden childhood deaths, clinical quality of care was assessed as poor in 11 (38%) and the death was considered avoidable or potentially avoidable in 16 (55%). The main themes identified from the caregivers were their perception of the quality of care delivered (driven by perceived healthcare worker effort, empathy and promptness), the way the family was dealt with during the final resuscitation, and communications at the time of and after the death. Ten (35%) caregivers were predominantly negative about the care delivered, of whom four received fair clinical quality of care; 13 (49%) of caregivers had predominantly positive experiences, one of whom received poor clinical quality of care. CONCLUSIONS: Caregivers' experiences of the healthcare service around their child's death are influenced largely by the way healthcare workers communicate with them, as well as the perceived clinical effort. This is not always concordant with the clinically assessed quality of care. Simple interventions such as protocols and education of healthcare workers in dealing with families of a dying or deceased child could improve families' experiences at a time when they are most vulnerable.

GoActive: a protocol for the mixed methods process evaluation of a school-based physical activity promotion programme for 13-14year old adolescents.

BACKGROUND: Process evaluations are critical for interpreting and understanding outcome trial results. By understanding how interventions function across different settings, process evaluations have the capacity to inform future dissemination of interventions. The complexity of Get others Active (GoActive), a 12-week, school-based physical activity intervention implemented in eight schools, highlights the need to investigate how implementation is achieved across a variety of school settings. This paper describes the mixed methods GoActive process evaluation protocol that is embedded within the outcome evaluation. In this detailed process evaluation protocol, we describe the flexible and pragmatic methods that will be used for capturing the process evaluation data. METHODS: A mixed methods design will be used for the process evaluation, including quantitative data collected in both the control and intervention arms of the GoActive trial, and qualitative data collected in the intervention arm. Data collection methods will include purposively sampled, semi-structured interviews and focus group interviews, direct observation, and participant questionnaires (completed by students, teachers, older adolescent mentors, and local authority-funded facilitators). Data will be analysed thematically within and across datasets. Overall synthesis of findings will address the process of GoActive implementation, and through which this process affects outcomes, with careful attention to the context of the school environment. DISCUSSION: This process evaluation will explore the experience of participating in GoActive from the perspectives of key groups, providing a greater understanding of the acceptability and process of implementation of the intervention across the eight intervention schools. This will allow for appraisal of the intervention's conceptual base, inform potential dissemination, and help optimise post-trial sustainability. The process evaluation will also assist in contextualising the trial effectiveness results with respect to how the intervention may or may not have worked and, if it was found to be effective, what might be required for it to be sustained in the 'real world'. Furthermore, it will offer suggestions for the development and implementation of future initiatives to promote physical activity within schools. TRIAL REGISTRATION: ISRCTN, ISRCTN31583496 . Registered on 18 February 2014.

GPs' perceptions of workload in England: a qualitative interview study.

BACKGROUND: GPs report the lowest levels of morale among doctors, job satisfaction is low, and the GP workforce is diminishing. Workload is frequently cited as negatively impacting on commitment to a career in general practice, and many GPs report that their workload is unmanageable. AIM: To gather an in-depth understanding of GPs' perceptions and attitudes towards workload. DESIGN AND SETTING: All GPs working within NHS England were eligible. Advertisements were circulated via regional GP e-mail lists and national social media networks in June 2015. Of those GPs who responded, a maximum-variation sample was selected until data saturation was reached. METHOD: Semi-structured, qualitative interviews were conducted. Data were analysed thematically. RESULTS: In total, 171 GPs responded, and 34 were included in this study. GPs described an increase in workload over recent years, with current working days being long and intense, raising concerns over the wellbeing of GPs and patients. Full-time partnership was generally not considered to be possible, and many participants felt workload was unsustainable, particularly given the diminishing workforce. Four major themes emerged to explain increased workload: increased patient needs and expectations; a changing relationship between primary and secondary care; bureaucracy and resources; and the balance of workload within a practice. Continuity of care was perceived as being eroded by changes in contracts and working patterns to deal with workload. CONCLUSION: This study highlights the urgent need to address perceived lack of investment and clinical capacity in general practice, and suggests that managing patient expectations around what primary care can deliver, and reducing bureaucracy, have become key issues, at least until capacity issues are resolved.

GP views on strategies to cope with increasing workload: a qualitative interview study.

BACKGROUND: The existence of a crisis in primary care in the UK is in little doubt. GP morale and job satisfaction are low, and workload is increasing. In this challenging context, finding ways for GPs to manage that workload is imperative. AIM: To explore what existing or potential strategies are described by GPs for dealing with their workload, and their views on the relative merits of each. DESIGN AND SETTING: Semi-structured, qualitative interviews with GPs working within NHS England. METHOD: All GPs working within NHS England were eligible. Of those who responded to advertisements, a maximum-variation sample was selected and interviewed until data saturation was reached. Data were analysed thematically. RESULTS: Responses were received from 171 GPs, and, from these, 34 were included in the study. Four main themes emerged for workload management: patient-level, GP-level, practice-level, and systems-level strategies. A need for patients to take greater responsibility for self-management was clear, but many felt that GPs should not be responsible for this education. Increased delegation of tasks was felt to be key to managing workload, with innovative use of allied healthcare professionals and extended roles for non-clinical staff suggested. Telephone triage was a commonly used tool for managing workload, although not all participants found this helpful. CONCLUSION: This in-depth qualitative study demonstrates an encouraging resilience among GPs. They are proactively trying to manage workload, often using innovative local strategies. GPs do not feel that they can do this alone, however, and called repeatedly for increased recruitment and more investment in primary care.

A cluster randomised controlled trial to evaluate the effectiveness and cost-effectiveness of the GoActive intervention to increase physical activity among adolescents aged 13-14 years.

INTRODUCTION: Adolescent physical activity promotion is rarely effective, despite adolescence being critical for preventing physical activity decline. Low adolescent physical activity is likely to last into adulthood, increasing health risks. The Get Others Active (GoActive) intervention is evidence-based and was developed iteratively with adolescents and teachers. This intervention aims to increase physical activity through increased peer support, self-efficacy, group cohesion, self-esteem and friendship quality, and is implemented using a tiered-leadership system. We previously established feasibility in one school and conducted a pilot randomised controlled trial (RCT) in three schools. METHODS AND ANALYSIS: We will conduct a school-based cluster RCT (CRCT) in 16 secondary schools targeting all year 9 students (n=2400). In eight schools, GoActive will run for two terms: weekly facilitation support from a council-funded intervention facilitator will be offered in term 1, with more distant support in term 2. Tutor groups choose two weekly activities, encouraged by older adolescent mentors and weekly peer leaders. Students gain points for trying new activities; points are entered into a between-class competition. Outcomes will be assessed at baseline, interim (week 6), postintervention (week 14-16) and 10-month follow-up (main outcome). The primary outcome will be change from baseline in daily accelerometer-assessed moderate-to-vigorous physical activity. Secondary outcomes include accelerometer-assessed activity intensities on weekdays/weekends; self-reported physical activity and psychosocial outcomes; cost-effectiveness and cost-utility analyses; mixed-methods process evaluation integrating information from focus groups and participation logs/questionnaires. ETHICS AND DISSEMINATION: Ethical approval for the conduct of the study was gained from the University of Cambridge Psychology Research Ethics Committee. Given the lack of rigorously evaluated interventions, and the inclusion of objective measurement of physical activity, long-term follow-up and testing of causal pathways, the results of a CRCT of the effectiveness and cost-effectiveness of GoActive are expected to add substantially to the limited evidence on adolescent physical activity promotion. Workshops will be held with key stakeholders including students, parents, teachers, school governors and government representatives to discuss plans for wider dissemination of the intervention. TRIAL REGISTRATION NUMBER: ISRCTN31583496.