Study design and setting
This was a group randomized controlled trial with outcomes assessed at baseline and 18-months post-randomization follow-up. It involved 24 secondary schools across seven regions in the state of New South Wales, Australia. There were no variations to the methods after the trial had commenced. The detailed methods of the study have been previously published and are readily available through an open access journal [13].
School and participant selection and recruitment
The NSW DEC sought expressions of interest from school principals (N = 500). Recruitment and consent of schools occurred in October 2008. Within each school, all girls in Grade 8 in 2009 were invited to participate. Girls needed to provide written consent from themselves and their parents. If a student or parent did not consent, they still participated in the intervention but did not in data collection.
Randomization
The school was the unit of randomization. Schools were matched into 12 pairs based on the following criteria: school size, proportion of students from non-English speaking and Indigenous backgrounds, teaching experience of PE staff, organization of school sport, school type, and geographic location. Each matched pair of school was randomly allocated, using a computer-based random number producing algorithm to intervention or control group by a researcher independent of the project who then communicated to the research team who informed each school of its allocation. Due to the timeframe of the study, formative research was required to be conducted in the intervention schools in October/November, 2008. This meant randomization needed to occur prior to baseline data collection.
Formative research
The formative research identified the needs and interests of adolescent girls, and from school staff, their perceptions of community facilitators and barriers to girls’ participation in physical activity. Interviews were held with relevant staff (including PE and non-PE teaching staff and a member of the school executive), and separate focus groups were conducted with groups of boys, and with girls in Grade 8. The Project Officer from the NSW DEC (SM) attended along with the Project Manager (LMP), who collected the data. In addition, participants were asked to map community physical activity facilities and opportunities on provided maps of the school and local community. Informal observations of PE lessons, recess and lunchtime activities were also conducted by the Project Manager. These were conducted in each of the 12 intervention schools. Between 1 and 3 observations were made during recess, lunch, and in PE lessons where possible and these were recorded as field notes.
Results suggested two main reasons schools were interested in participating in the study. These were the chance to “revitalize” sport in their school and the opportunity to engage particular groups of girls who were currently not participating enthusiastically in PE or sport. Staff believed the reasons for girls not participating in school sport were: 1) how it was structured, which lacked variety and limited choice, with those who were less skilled and confident being the last to choose a sport; 2) the lack of resources; and 3) the lack of expertise among non-PE teaching staff who supervised school sport. Among the girls, the main reasons for their non-participation were similar to those reported by staff, with additional barriers identified including the “dominating” behaviors of boys during PE and sport and their perceived lack of skills and confidence.
Girls were asked what they would like included in a school sport program. They suggested the opportunity to choose some of the activities (especially non-traditional activities) and to participate with their friends; having motivated teachers, more modern sports uniforms, and more respectful behavior from boys; and higher levels of activity during sessions. These suggestions were consistent with those cited in the literature [12, 14,15,16].
Results were provided to each school and school committees were asked to consider them when developing their intervention strategies and action plans. For example, staff were encouraged to survey girls to determine what activities they would like to participate in and then examine ways some of them could be integrated into their school sport programs. Schools were advised of the importance of students being a part of the school sports committee so they had a “voice” in their school.
Intervention
Using a Health Promoting Schools framework [17, 18] and Action Learning approach [19], schools developed unique 18-month action plans. A member of the research team was assigned to be a “critical friend” at each school. This involved working with the school as it collected and interpreted its own data and assisting with the development and implementation of the school’s action plan [20]. The intervention strategies were designed to achieve the primary aim of the project. This aim was the same for each school, to prevent a decline in participation in moderate- to vigorous-intensity physical activity (MVPA) levels among girls over the course of the intervention. Secondary outcomes for the project were for schools to provide programs better designed to meet the needs of girls and to make girls aware of these, and more functional links to activities in the community. These were measured through the process evaluation. Improving confidence and self-efficacy in physical activity participation was also an additional outcome that was assessed through a psyschosocial questionnaire. Each school followed an identical process in developing their intervention. This involved:
-
1)
Forming an action learning team (referred to as a Committee) within their school community. Schools were advised that this committee should comprise an executive level teacher, program champion, at least two other teachers, and at least two female students from the designated Grade group.
-
2)
Developing school-specific action plans in three areas based on the results of the formative research and on individual needs of the school.
These three areas that constituted the “active component” of the intervention were the “formal” curriculum, school environment, and links with the community [21]. A specific description of how schools typically targeted each of these areas is described as follows:
Formal curriculum
The main focus of this area was to enhance school sport. Schools did this by trying to engage girls for at least 50% of the class time in moderate- to vigorous-intensity physical activity (MVPA) while reducing time spent in management tasks (e.g., organising students). An additional aim was for teachers to promote physical activity in and out of class. Activities were also targeted that girls indicated through the formative research that they would like to participate in. These included recreational and non-traditional activities such as power walking, yoga, Pilates, Zumba®, boxing-related fitness, and skipping activities.
School environment
Modifying the school ethos or environment aimed to raise awareness of the benefits of physical activity and sport at the school level. Schools took the approach that making sustainable changes involved more than implementing activities – it required a change in how they valued school sport and physical activity and embedded it into the school culture. Each school’s action learning team (or Committee) drove this intervention component. The Committee’s role was to advocate for the intervention within the school. They were responsible for developing and implementing initiatives that they believed would be sustainable. Schools were provided with information from the research team to inform the development of this component [10, 13, 22,23,24,25], which included lunchtime and after-school activity programs, modifying school policies related to use of equipment and facilities, allowing students to wear sports uniforms to school on sports days, gala afternoons, and aligning the school Awards/Merit system with the intervention.
Links with the community
To enhance links with the local community, schools sought professional development from the research team in how to promote out of school activity during the school sport sessions. This included making explicit links, such as using local facilities (e.g., fitness centres, PCYC’s, indoor rock climbing and sports centres). Others involved teachers identifying and prompting sports and activities available in the local community (e.g., basketball, touch football, tennis, soccer) during school sport and organising representatives (such as Development Officers) from these organisations to visit the school. Local community providers were also asked to offer classes and incentives for girls to participate.
Each school’s specific action plan formed part of the overall school plan for the year. School plans provide a framework to drive change within a school over a 3-year period in areas such as student engagement and retention, teacher quality, and connected learning [26]. Schools documented strategies to address each of the outcomes of their action plan, including who would be involved and how they would measure success.
During the intervention, schools participated in monthly meetings with their critical friend to share their progress towards the study outcomes. Schools were encouraged to modify strategies and, if further assistance was required, this was discussed between the research team and NSW DEC staff and communicated back to the school.
Support was given to the schools through funding from the NSW DEC to support implementation and for staff to attend professional development activities. These activities included an initial two-day training program, and a two-day research symposium mid-way through the intervention period (Feb 2010). In addition, if a school requested specific professional development in an area and a member of the research team was able to provide this, they did so. For example, several of the schools wanted suggestions for activities to run in a lunch-time gym class/boot camp for girls and one of the research team delivered a professional development session for them on this. Regular contact was provided by the Girls in Sport Project Manager who was employed by the NSW DEC.
Control schools
Control schools continued with their usual programs. At the conclusion of the project these schools received training and materials related to the findings of the project. Staff also attended the final Research Colloquium in February 2011.
Data collection procedures
Trained data collectors were blinded to group allocation. Baseline data were collected between February, 2009 and June, 2009 and follow-up data between July, 2010 and December, 2010. Data were collected at the same time in each pair of matched schools. Teachers and students were kept blinded to their matched comparison school. Each data collector was given a detailed manual, checklist and scripts to read when informing the participants of the measures.
Measures
Primary outcome
Accelerometer measured total physical activity (TPA) [27] spent in physical activity was the primary outcome for the study. All participants wore an Actigraph accelerometer (7164 and GT1M models; Fort Walton Beach, FL) for one week. Thirty-second activity counts were uploaded to determine time spent in light (1.5 to 3.9 METs) moderate (4.0 to 6.9) and vigorous (≥7.0) activity. Age-specific count ranges relating to the above intensity levels were based on prediction equations for energy expenditure [28]. Values were calculated for percentage of monitored time spent in light, moderate, and vigorous physical activity to account for variation in wear time. Participants also received two text messages reminding them to wear the accelerometers and to return them at the end of the 7-day period.
Secondary outcomes
Psychosocial outcomes were assessed by questionnaire and included enjoyment of physical activity and school sport [29], physical activity self-efficacy [30], peer support for physical activity [31], social support during school sport [32], strategies to increase physical activity [33], school physical activity environment, physical self-concept, and perceived importance of physical activity [34]. Validity and reliability testing of all psychosocial outcomes has been reported [13].
Process evaluation
At the end of the first year, schools documented their progress towards the study outcomes based on implementation of their specific strategies. Interviews were conducted at the end of the intervention with each Girls in Sport school committee, staff, and students to assess the extent to which the strategies were implemented. Girls were asked to indicate if there had been any changes to school sport over the past 18 months, if they were asked to suggest how to improve school sport, if they were informed about sports in the local community, and if any lunchtime activity programs were implemented.
Qualitative data
There was a qualitative component to this project. It was designed to triangulate the quantitative results and provide knowledge about how Girls in Sport was implemented in each school, what influenced what happened in each school and whether the project had an impact on the girls targeted by the school. That is, the girls who seemed to be most disengaged from school sport and physical activity. The qualitative component, through its descriptions of what seemed to be the most and least successful components of the project and schools responses to the project, was also able to provide some recommendations and ideas for future policy and practice in relation to school based sport and physical activity outside the PE lesson.
The qualitative data were collected through the following methods:
-
Formative individual and group interviews were conducted prior to the implementation of the project in each intervention school with the executive, both PE teachers and teachers from other key learning areas, at least eight Year 8 girls and three or four Year 8 boys at most schools;
-
Individual and group interviews in comparison schools;
-
Identification of the most disengaged case study girls (six per school): one individual interview and one final group interview;
-
Final individual and group interviews with executive, teachers, girls and some boys where possible in the intervention and comparison schools;
-
Ongoing observations by the critical friend on school visits, school reports at workshops and Girls in Sport conferences, school planning documents and regular Chief Investigator reports on the progress of the school with which they were associated.
These data are not reported on in this study but are being written up separately. However, qualitative data have been used to explain some of the quantitative findings in this paper.
Sample size
In the absence of a reliable estimate of the intra-class correlation for the primary outcome measure of accelerometer-derived total physical activity (TPA) an estimate of 0.01 was used in the a priori calculations. Effect sizes and variance estimates, 77.51 (SD102.92) TPA, which was 18.4% of the baseline mean, were obtained from a previous study [10]. Using these figures, a model based on a critical t-value of 2.228 (taking into consideration the matching of the schools) was obtained for estimates based on 12 schools per group. Variance estimates were adjusted for clustering as proposed by Murray [35] where the standard error of the estimate in the usual t-estimation was replaced by \( \sqrt{\frac{2\left({\widehat{\sigma}}_m^2+ m{\widehat{\sigma}}_g^2\right.}{ m g}} \) where \( {\widehat{\sigma}}_m^2 \) is the estimate of the unadjusted subject component of the variance, \( {\widehat{\sigma}}_g^2 \) is the unadjusted school component of the variance, m is the number of subjects per school and g is the number of schools per group. Sample sizes as low as 10 participants per school completing the study provided adequate power (>80% power and P < 0.05). Given that the estimate of effect could be considered optimistic for the present design a more modest effect size (10% of baseline mean, 42.07 TPA) was also considered. It was also anticipated that group sizes would vary between schools and therefore the estimates were based on a harmonic mean of 30 participants per school completing [36]. With this conservative mean effect size and a harmonic mean sample size of 30 completing the study, the power still remained high (0.987).
Statistical analyses
Statistical analyses of the primary outcome variable, accelerometer-derived counts per minute, were performed using a linear mixed model (PROC MIXED) in SAS (version 9.2, SAS Inc, Cary NC) between December 2011 and March 2012. All models accounted for the hierarchical structure of the data. Analyses were not adjusted for multiple comparisons. Analyses involving mins/day for light, moderate, vigorous, and MVPA were adjusted for accelerometer type. Student data were included in the analyses if the accelerometer was worn for >600mins/day on at least 3 days [37]. Analyses followed intention-to-treat principles. An advantage of the linear mixed model is that it can incorporate all available data allowing for the analysis of partial datasets created when a participant drops out of the study or misses a study visit. Imputation of missing data was also performed on the accelerometer data due to the large amount of missing data at follow-up. This imputation was performed using PROC MI and MIANALYSE. Sensitivity analyses were performed. Linear mixed models were also used to analyze all continuous accelerometer-derived outcome variables (time in minutes and percentage of time spent in sedentary behavior, light, moderate and vigorous intensity physical activity) and all secondary outcome variables.
Per protocol analyses were also completed on four schools that were deemed, a priori to have met all the criteria for having implemented the intervention as planned. These criteria included six key areas (see Additional file 1: Table S1). These were compared with their matched control school. During the analyses, one of the schools and its matched control school were too small to include in the analysis. As such, only three intervention schools were analyzed together and compared with their matching schools.
