Examination of mid-intervention mediating effects on objectively assessed sedentary time among children in the Transform-Us! cluster-randomized controlled trial

Abstract

BackgroundThe optimal targets and strategies for effectively reducing sedentary behavior among young people are unknown. Intervention research that explores changes in mediated effects as well as in outcome behaviors is needed to help inform more effective interventions. Therefore, the purpose of this study was to examine the mid-intervention mediating effects on children’s objectively assessed classroom and total weekday sedentary time in the Transform-Us! intervention.MethodsThe results are based on 293 children, aged 7- to 9-years-old at baseline, from 20 schools in Melbourne, Australia. Each school was randomly allocated to one of four groups, which targeted reducing sedentary time in the school and family settings (SB; n = 74), increasing or maintaining moderate- to vigorous-intensity physical activity in the school and family settings (PA; n = 75), combined SB and PA (SB + PA; n = 80), or the current practice control (C; n = 64). Baseline and mid-intervention data (5–9 months) were collected in 2010 and analyzed in 2012. Classroom and total weekday sedentary time was objectively assessed using ActiGraph accelerometers. The hypothesized mediators including, child enjoyment, parent and teacher outcome expectancies, and child perceived access to standing opportunities in the classroom environment, were assessed by questionnaire.ResultsThe SB + PA group spent 13.3 min/day less in weekday sedentary time at mid-intervention compared to the control group. At mid-intervention, children in the SB group had higher enjoyment of standing in class (0.9 units; 5-unit scale) and all intervention groups had more positive perceptions of access to standing opportunities in the classroom environment (0.3-0.4 units; 3-unit scale), compared to the control group. However, none of the hypothesized mediator variables had an effect on sedentary time; thus, no mediating effects were observed.ConclusionsWhile beneficial intervention effects were observed on some hypothesized mediating variables and total weekday sedentary time at mid-intervention, no significant mediating effects were found. Given the dearth of existing information, future intervention research is needed that explores mediated effects. More work is also needed on the development of reliable mediator measures that are sensitive to change overtime.Trial registrationACTRN12609000715279ISRCTN83725066

Findings From the EASY Minds Cluster Randomized Controlled Trial: Evaluation of a Physical Activity Integration Program for Mathematics in Primary Schools

“…Furthermore, these reductions in sitting time may partly explain why students were more on task during class time as previous studies have demonstrated the importance of activity breaks in increasing students on task behavior 12 . Whilst little is known about students' perceptions of sitting for prolonged periods throughout the school day, a recent primary school physical activity intervention on sedentary time has observed a significant intervention effect on child-reported enjoyment of standing in the classroom during the school day 51 .…”

Impact of an 8-Month Trial Using Height-Adjustable Desks on Children’s Classroom Sitting Patterns and Markers of Cardio-Metabolic and Musculoskeletal Health

“…In children, the Transform-Us! intervention used pedagogical strategies (e.g., 2-min standing breaks from sitting and daily 30-min standing lessons) in conjunction with standing easels and observed a 13 min/day reduction in classroom sitting time among Australian 8–9 year olds after 6 months [39]. In contrast, the European intervention, UP4FUN, used curriculum-based education strategies only (without changes to pedagogy or the classroom environment) that focused on teaching children the importance of reducing sitting and increasing physical activity.…”

“…Teacher-guided pedagogical approaches encouraging students to use the desks may enhance the effectiveness of such interventions on reducing and breaking-up sitting time. Previous research has examined the impact of teacher professional development sessions with pedagogical approaches during lessons in the absence of height-adjustable desks and observed a 13 min per day reduction in classroom sitting time [38,39]. However, the combination of pedagogical approaches and height-adjustable desks has not been investigated.…”

A primary school active break programme (ACTI-BREAK): study protocol for a pilot cluster randomised controlled trial

“…years 2/3 or years 4/5 composites) were not eligible. Based on a 37% response rate (as demonstrated in a similar study conducted in the Australian school context [ 38 ]) and an average class size in Victorian schools of 23 students per class [ 39 ], we anticipate that nine students per class will consent to take part in this pilot study. For feasibility reasons, the intention is to recruit six schools (three intervention and three control) from which a sample size of 216 children is estimated (six schools × four classes (two classes per year level) [ 40 ] × nine students).…”