ter baseline data collection at the relevant school. The schools are informed of their allocated treatment after baseline data collection.
Unstructured materials are introduced on the school playgrounds to be used during recess. The materials are selected to conform to seven principles: 1. no obvious play value; 2. encourage cooperative, gross motor play; 3. have multiple uses; 4. can be used in challenging, creative and uncertain ways; 5. provide interesting sensory experiences (e.g., from touch or movement); 6. inherent hazards can easily be seen/managed by a child; 7. are, or are made from, re-cycled materials. Examples of items include car tyres, milk crates, and cardboard boxes; in some cases these are reinforced or made more water resistant (e.g., by drilling tyres or covering cardboard with plastic tape). Some items, such as crash mats, are fabricated from recycled objects. All materials are checked for safety characteristics and child-proofed; all meet Australian standards for playground materials. New materials are introduced periodically to replace broken objects or to complement existing objects. Maintenance of the materials is the responsibility of researchers in collaboration with each school community but school staff must agree to remove materials that are broken or being used in unsafe ways.
This intervention runs in each intervention school over 2 terms (13 weeks total), during which time children are able to use and play freely with the items. The materials are for the use of all children at the school, independent of project consent.
Adult intervention: Risk Reframing
Teachers and parents of participating children from the intervention schools are asked to participate in a 2-hour group intervention. The adults participate in small "task groups" (n = 6-8) as well as large whole-group discussions (N = 18-24) to examine their own experiences of free play and their beliefs regarding the benefits and risks associated with active play. Discussions focus on similarities and differences of parents' and teachers' perceptions of the benefits of play, healthy (or manageable) vs. unhealthy risk and the consequences of preventing children from engaging in play and healthy risk taking. Schools are offered compensation for the time the teachers are participating in the sessions.
The control schools participate in standard recess, and they do not have access to the unstructured materials or to risk reframing.
Outcome measures and schedule of the study
Stadiometer and scales
Researcher with child
Height and weight
Actigraph accelerometer 1
Devices worn by children
Counts, and minutes in sedentary and moderate to vigorous activity
Activity Diary 2
Palm pilots responded on by parents
Activities undertaken after school
Parent and teacher reports
Social skills and problem behaviour
Researcher with child, and teacher reports
Feelings of competence
Physical activity during school days
Actigraph accelerometers (GT3X, http://www.theactigraph.com) are worn on the participating children's right hip, on the iliac bone, on top of clothing and fastened with an elastic waist band. A researcher attaches the accelerometers at 9.00 AM and removes them at 3.00 PM for 5 consecutive school days. Movement is measured in three planes at 5 second epochs.
Data are downloaded from the accelerometers using the product-coupled software ActiLife and stored as .dat files to be used in subsequent analyses. To measure the level of physical activity, total accelerometer counts, as well as minutes and percent of time spent in sedentary, light, moderate and vigorous physical activities are calculated, using a custom-made macro (Stewart Trost). The cut-points for levels of physical defined by Evenson et al.  are used. Accelerometer non-wear time is defined as a count of 0 for 10 consecutive minutes .
Children's activities after school
We collect information about activities during after-school hours (between 3.30 PM and 7.00 PM) in both baseline and post-test sessions using a real-time activity diary. Responses to the activity diary are recorded at thre