BackgroundBehaviour change interventions that promote physical activity have major implications for health and well-being. Measuring intervention fidelity is crucial in determining the extent to which an intervention is delivered as intended, therefore increasing scientific confidence about effectiveness. However, we lack a clear overview of how well intervention fidelity is typically assessed in physical activity trials.MethodsA systematic literature search was conducted to identify peer - reviewed physical activity promotion trials that explicitly measured intervention fidelity. Methods used to assess intervention fidelity were categorised, narratively synthesised and critiqued using assessment criteria from NIH Behaviour Change Consortium (BCC) Treatment Fidelity Framework (design, training, delivery, receipt and enactment).ResultsTwenty eight articles reporting of twenty one studies used a wide variety of approaches to measure intervention fidelity. Delivery was the most common domain of intervention fidelity measured. Approaches used to measure fidelity across all domains varied from researcher coding of observational data (using checklists or scales) to participant self-report measures. There was considerable heterogeneity of methodological approaches to data collection with respect to instruments used, attention to psychometric properties, rater-selection, observational method and sampling strategies.ConclusionsIn the field of physical activity interventions, fidelity measurement is highly heterogeneous both conceptually and methodologically. Clearer articulation of the core domains of intervention fidelity, along with appropriate measurement approaches for each domain are needed to improve the methodological quality of fidelity assessment in physical activity interventions. Recommendations are provided on how this situation can be improved.Electronic supplementary materialThe online version of this article (10.1186/s12889-017-4778-6) contains supplementary material, which is available to authorized users.

Background: Physical activity during childhood is associated with multiple short- and long-term health benefits. Physical activity levels decline throughout primary school emphasising a need for effective strategies to promote more activity in children. Children have rarely been involved in the intervention development process. This gap is an important omission and there is much to be learnt from existing qualitative studies with children, which could serve as a starting point for specific projects. This systematic review aimed to synthesise qualitative studies with primary school children in the United Kingdom to identify children’s perspectives on why physical activity is important, the factors that influence their physical activity and what they like when it comes to physical activity. Methods: A search of seven databases (conducted in October 2019) identified 26 papers for inclusion. Data extraction and synthesis were conducted using qualitative thematic synthesis. The quality of papers was assessed using the Critical Appraisal Skills Programme checklist for qualitative research. Results: Across the diverse range of studies, several key themes were identified in relation to the three research questions. Children have a comprehensive understanding of the various benefits of physical activity, including benefits for health, fitness and skills development. A range of social agents and practical issues influence children’s physical activity, with friend and peer influences being particularly salient. Most children like to have choice over the activities they undertake and the opportunities for creative physical play such as making up active games. Conclusions: The findings suggest that future interventions should utilize peer relationships, ensure a variety of activities are offered to cater to a broad range of children’s physical activity preferences and incorporate child-led activities where possible. The included studies also highlight a need for more diversity in qualitative research in this area, particularly in terms of ethnicity and age, and combining traditional qualitative methods with creative methods, such as photography, may provide richer insights than when using a single mode of data collection. We also highlight several methodological challenges, and in particular, the need for greater acknowledgement of the role of the researcher in qualitative work with children.

Background Challenges of recruitment to randomized controlled trials (RCTs) and successful strategies to overcome them should be clearly reported to improve recruitment into future trials. REtirement in ACTion (REACT) is a United Kingdom-based multicenter RCT recruiting older adults at high risk of mobility disability to a 12-month group-based exercise and behavior maintenance program or to a minimal Healthy Aging control intervention. Methods The recruitment target was 768 adults, aged 65 years and older scoring 4–9 on the Short Physical Performance Battery (SPPB). Recruitment methods include the following: (a) invitations mailed by general practitioners (GPs); (b) invitations distributed via third-sector organizations; and (c) public relations (PR) campaign. Yields, efficiency, and costs were calculated. Results The study recruited 777 (33.9% men) community-dwelling, older adults (mean age 77.55 years (SD 6.79), mean SPPB score 7.37 (SD 1.56)), 95.11% white (n = 739) and broadly representative of UK quintiles of deprivation. Over a 20-month recruitment period, 25,559 invitations were issued. Eighty-eight percent of the participants were recruited via GP invitations, 5.4% via the PR campaign, 3% via word-of-mouth, and 2.5% via third-sector organizations. Mean recruitment cost per participant was £78.47, with an extra £26.54 per recruit paid to GPs to cover research costs. Conclusions REACT successfully recruited to target. Response rates were lower than initially predicted and recruitment timescales required adjustment. Written invitations from GPs were the most efficient method for recruiting older adults at risk of mobility disability. Targeted efforts could achieve more ethnically diverse cohorts. All trials should be required to provide recruitment data to enable evidence-based planning of future trials.

Background Fidelity assessment of behaviour change interventions is vital to understanding trial outcomes. This study assesses the delivery fidelity of behaviour change techniques used in the Retirement in ACTion (REACT) randomised controlled trial. REACT is a community-based physical activity (PA) and behaviour maintenance intervention to prevent decline of physical functioning in older adults (≥ 65 years) at high risk of mobility-related disability in the UK. Methods The delivery fidelity of intervention behaviour change techniques and delivery processes were assessed using multi-observer coding of purposively sampled in-vivo audio recordings (n = 25) of health behaviour maintenance sessions over 12-months. Delivery fidelity was scored using a modified Dreyfus scale (scores 0–5) to assess competence and completeness of delivery for each technique and delivery process. “Competent delivery” was defined as a score of 3 points or more for each item. Examples of competent intervention delivery were identified to inform recommendations for future programme delivery and training. Results The mean intervention fidelity score was 2.5 (SD 0.45) with delivery fidelity varying between techniques/processes and intervention groups. Person-centred delivery, Facilitating Enjoyment and Promoting Autonomy were delivered competently (scoring 3.0 or more). There was scope for improvement (score 2.0—2.9) in Monitoring Progress (Acknowledging and Reviewing), Self-Monitoring, Monitoring Progress (Eliciting Benefits of Physical Activity), Goal Setting and Action Planning, Modelling, Supporting Self-Efficacy for Physical Activity and Supporting Relatedness. Managing Setbacks and Problem Solving was delivered with low fidelity. Numerous examples of both good and sub-optimal practice were identified. Conclusions This study highlights successes and improvements needed to enhance delivery fidelity in future implementation of the behavioural maintenance programme of the REACT intervention. Future training of REACT session leaders and assessment of delivery fidelity needs to focus on the delivery of Goal setting and Action Planning, Modelling, Supporting Relatedness, Supporting Self-Efficacy for Physical Activity, and Managing Setbacks/ Problem Solving.

Background Mobility limitation in older age reduces quality of life, generates substantial health- and social-care costs, and increases mortality. Objective The REtirement in ACTion (REACT) trial aimed to establish whether or not a community-based active ageing intervention could prevent decline in physical functioning in older adults already at increased risk of mobility limitation. Design A multicentre, pragmatic, two-arm, parallel-group randomised controlled trial with parallel process and health economic evaluations. Setting Urban and semi-rural locations across three sites in England. Participants Physically frail or pre-frail older adults (aged ≥ 65 years; Short Physical Performance Battery score of 4–9). Recruitment was primarily via 35 primary care practices. Interventions Participants were randomly assigned to receive brief advice (three healthy ageing education sessions) or a 12-month, group-based, multimodal exercise and behavioural maintenance programme delivered in fitness and community centres. Randomisation was stratified by site and used a minimisation algorithm to balance age, sex and Short Physical Performance Battery score. Data collection and analyses were blinded. Main outcome measures The primary outcome was change in lower limb physical function (Short Physical Performance Battery score) at 24 months, analysed using an intention-to-treat analysis. The economic evaluation adopted the NHS and Personal Social Services perspective. Results Between June 2016 and October 2017, 777 participants (mean age 77.6 years, standard deviation 6.8 years; 66% female; mean Short Physical Performance Battery score 7.37, standard deviation 1.56) were randomised to the intervention arm (n = 410) or the control arm (n = 367). Data collection was completed in October 2019. Primary outcome data at 24 months were provided by 628 (80.8%) participants. At the 24-month follow-up, the Short Physical Performance Battery score was significantly greater in the intervention arm (mean 8.08, standard deviation 2.87) than in the control arm (mean 7.59, standard deviation 2.61), with an adjusted mean difference of 0.49 (95% confidence interval 0.06 to 0.92). The difference in lower limb function between intervention and control participants was clinically meaningful at both 12 and 24 months. Self-reported physical activity significantly increased in the intervention arm compared with the control arm, but this change was not observed in device-based physical activity data collected during the trial. One adverse event was related to the intervention. Attrition rates were low (19% at 24 months) and adherence was high. Engagement with the REACT intervention was associated with positive changes in exercise competence, relatedness and enjoyment and perceived physical, social and mental well-being benefits. The intervention plus usual care was cost-effective compared with care alone over the 2 years of REACT; the price year was 2019. In the base-case scenario, the intervention saved £103 per participant, with a quality-adjusted life-year gain of 0.04 (95% confidence interval 0.006 to 0.074) within the 2-year trial window. Lifetime horizon modelling estimated that further cost savings and quality-adjusted life-year gains were accrued up to 15 years post randomisation. Conclusion A relatively low-resource, 1-year multimodal exercise and behavioural maintenance intervention can help older adults to retain physical functioning over a 24-month period. The results indicate that the well-established trajectory of declining physical functioning in older age is modifiable. Limitations Participants were not blinded to study arm allocation. However, the primary outcome was independently assessed by blinded data collectors. The secondary outcome analyses were exploratory, with no adjustment for multiple testing, and should be interpreted accordingly. Future work Following refinements guided by the process evaluation findings, the REACT intervention is suitable for large-scale implementation. Further research will optimise implementation of REACT at scale. Trial registration This trial is registered as ISRCTN45627165. Funding This project was funded by the National Institute for Health and Care Research (NIHR) Public Health Research programme and will be published in full in Public Health Research; Vol. 10, No. 14. See the NIHR Journals Library website for further project information.