Limitations
As previously noted, the Play Active policy intervention was limited by a short implementation period and lack of educator use of the resource guide and online professional development. Additional limitations relate to the self-selected ECEC sample, measurement methods, and broader challenges within the ECEC sector. The self-selection of services into the trial could have introduced some bias as these services may have been more likely to implement the policy and/or report more desirable physical activity outcomes. The high proportion of educators at baseline reporting they were providing policy-recommended amounts of physical activity suggests this may have been the case, however, it may also indicate the intervention would have greater effect among ECEC services not self-selecting into a trial, including services located in regional, remote, and disadvantaged areas.While based on established instruments [Challenges within the Australian ECEC sector were exacerbated during the COVID-19 pandemic and in turn impacted the study. During the pandemic, high staff turnover rates and understaffing were common in the sector [