There is increasing evidence of interventions shown to be effective to promote physical activity in adolescents with cancer. Nevertheless, adolescents with cancer become physically inactive after the end of the interventions. These interventions emphasized heavily on interventionists' role to assess adolescents' physical fitness and prescribe exercises. After the intervention, the adolescents were unable to follow the previous exercise prescriptions due to their changing medical conditions. To promote physical activity sustainably, it is vital to develop a patient-based assessment tool to allow adolescents with cancer to self-assess their own appropriate levels of physical activity that they could perform. However, a review of literature indicates a lack of such a tool.

A cross-sectional study design will be used. A convenience sample of 400 adolescents who (1) are aged 13-18; (2) are diagnosed with cancer; (3) can communicate in Cantonese and read Chinese will be recruited in Hong Kong Children's Hospital. The outcome measures will include demographic characteristics, pain scores, cardiopulmonary function measurements, EFT scores and ratings of the physiotherapists for the fitness of subjects for physical activity.

Inclusion Criteria:

• Aged 13-18
• are diagnosed with cancer
• are able to communicate in Cantonese and read Chinese

Exclusion Criteria:

Those with physical or cognitive impairments and learning problems, as identified from the medical records, were excluded. Also, those with medical advice that physical activity was not recommended or with detailed exercise prescriptions from physicians or physiotherapists during recruitment were excluded.

A convenience sample of 400 adolescents who meet the eligibility criteria will be invited to participate. Subjects will be recruited in non-governmental organizations and Hong Kong Children's Hospital which is the largest hospital in Hong Kong for admitting adolescents with cancer for hospitalization and follow-ups.