Inadequate mental health care capacity is a long-standing issue in Hong Kong (Yang & Mak, 2020). For example, a recent study predicts an additional 12% service need for specialist psychiatric care (Ni et al., 2020). It would be helpful to develop interventions that would ease the high demand of the health care system. Physical activity has been shown to reduce depressive symptoms in a number of studies (Bellón et al., 2021; Josefsson et al., 2014; Kvam et al., 2018; Schuch et al., 2016). Its flexibility and low-cost nature make physical activity a good intervention option for depressed individuals to do it anytime and anywhere.

This study aims to investigate the effect of physical activity intervention in the format of self-defence training on depressive symptoms. Around 40 eligible participants with at least moderate level of depressive symptoms will be randomly assigned to the physical activity (PA) group and waitlist (WL) control group. The PA group will receive a 6-week home-based self-defence training programme consisting of 120 min video training (including daily practice time) per week. Self-report questionnaires will be collected at baseline, immediate post-intervention, and 4-week follow up assessments. The primary outcome measure will be the Patient Health Questionnaire-9 to evaluate depression severity. Secondary outcomes will include psychological health symptoms, sleep quality, lifestyle, and quality of life. This research will provide new perspectives on the application of physical activity in the form of self-defence training as an intervention for depressive individuals.

Inclusion Criteria:

• 18 to 65 years old
• Hong Kong Residents
• Patient Health Questionnaire (PHQ-9) score ≥ 10; and
• Willingness to provide informed consent and comply with the trial protocol.

Exclusion Criteria:

• Patients with any cardiovascular diseases
• Receiving psychological treatment or medication for psychiatric disorders
• Participated in self defence training in the past 6 months