Research has consistently shown that children worldwide live an increasingly sedentary lifestyle, yet to date, physical activity (PA) interventions have achieved limited effectiveness. Empirical evidence suggests that the tendency to engage in recurrent thoughts about negative experiences (termed ‘emotional rehearsal’) is associated with negative PA behavioural change and increased cardiovascular disease risks in children. Since the design of PA interventions is seldom informed by the children, it is possible that certain aspects of these interventions may have unintentionally prompted emotional rehearsal about their PA experiences, especially for the sedentary individuals, leading to intervention futility. Therefore, the aims of this study were to 1) to qualitatively identify aspects of PA that Chinese children (aged 6–12) emotionally rehearse about and 2) to examine if PA‐specific emotional rehearsal might be linked to habitual PA and physical self‐concept. Three prominent themes emerged from the focus group interviews – fear for unfavourable external factors, physical functioning and bodily concerns. Regression analysis showed that habitual PA and physical self‐concept were significant predictors of PA‐specific emotional rehearsal. Our findings can potentially inform future PA interventions for Chinese children. Crucially, public health initiatives should encourage input from children in their design for potentially greater success in positive health behavioural change.