Objectives: (1) to evaluate the feasibility of innovative school-based interventions on health outcomes (psychological well-being, depressive symptoms, anxiety symptoms, physical activity, sleep duration, and sleep quality) among primary students in the post-COVID-19 pandemic period; (2) to explore children's experience of intervention; (3) to evaluate the effects of innovative school-based (WeJoy + WeHop) on depressive symptoms, physical activities, and sleep quality among primary 3 to 5 school children.

Method: Two phases of the study will be conducted, including feasibility pilot study and main study. In phase 1, a sample of 40 school children will be recruited from two community centers for feasibility test and semi-structured individual face-to-face interview. In phase 2, a total of 408 school children will be recruited from primary schools in Hong Kong. This study will adopt a 2 two-group pre and post-design. Participants are randomly assigned equally into 1 intervention group (WeJoy+WeHop) and 1 control group (Routine Extra curriculum Activity). Participants will be assessed at baseline and post-intervention. The outcomes are depressive symptoms, physical activities, and sleep quality, using the Chinese version of the Center for Epidemiologic Studies Depression Scale for Children (CES-DC), the Chinese Version of the International Physical Activity Questionnaire (IPAQ-C), and the Chinese version of the Pittsburgh Sleep Quality Index (PSQI-C).

Data analysis: Descriptive and inferential statistics will be performed to examine the research objectives.

The COVID-19 pandemic has altered children's lifestyles, calling for particular attention. Psychological problems, obesity, and sleep disturbance in children have become more prevalent throughout the COVID-19 outbreak. It is vital to develop preventative interventions to enhance psychological well-being, prevent obesity, and improve sleep health. Cognitive behavioural therapy (CBT) is effective in preventing psychological problems, obesity, and sleep problems in children. The provision of CBT faces obstacles such as a shortage of therapists, stigma, protracted wait times, and high costs. Evidence revealed that children prefer interventions with interactive, relatable, and game-like content to improve their engagement.

School-based CBT (WeJoy) allows children to recognize, change, and partake in pleasant activities based on the CBT model. The WeJoy comprises six weekly sessions on psychoeducation, cognitive restructuring, behavioural activation, emotional regulation, and self-monitoring. Exergaming on the interactive floor (WeHop) using a portable interactive projector games system. The WeHop can gain a sense of autonomy, competence, and relatedness to help them regulate their emotions and maintain positive behaviours according to the Self-Determination Theory. Children participate in the interactive floor games by stepping on various targets and moving in response to the game's rules. Combining task division, cooperation, and taking turns constitutes the collaboration mechanism.

Inclusion Criteria:

• Primary students ranged from primary 3 to 5 school children.
• Obtained consent forms from their legal guardians.

Exclusion Criteria:

• Primary students in primary 1 due to the adaptation of the new environment.
• Primary 6 due to the preparation of the examinations for secondary schools.

The data does not collect yet and the research team does not decide the plan to share IPD.