The impact of cancer on theory of planned behavior measures and physical activity levels during the first weeks following cancer diagnosis in children.

BACKGROUND: The theory of planned behavior (TPB) is used to document children's health behaviors linked to their physical activity. The TPB model and its components have been applied to comprehend the adoption of physical activity along informational and motivational parameters. Thus, this exploratory study aims to assess the evolution of children's physical activity levels (MVLPA) during the first weeks of their cancer, in addition to documenting the evolution of the TPB measures, self-reported fitness, and self-esteem in the physical domain to better understand children's physical activity behavior. METHODS: A total of 16 children (8 boys and 8 girls) with cancer answered psychosocial questionnaires at the diagnosis of cancer (time 1) and at 6 to 8 weeks (time 2) to assess the TPB measures, self-reported fitness, self-esteem in the physical domain, and their daily physical activities. RESULTS: A significant decrease of 41.2 min/days of daily MVLPA was observed between the time at cancer diagnosis (50.5 ± 32.8 min/days) and 6 to 8 weeks after the first interview (9.3 ± 9.1 min/days). We found that the time after the diagnosis of cancer negatively impacted children's TPB measures (mean in attitude, injunctive norms, identity, facilitating factors, self-confidence, and intention) and MVLPA levels. The TPB model explains 40% of the variance in MVLPA by the injunctive norms during the first weeks following cancer diagnosis in children. CONCLUSION: The findings of this study highlight the negative impacts of cancer on children's TPB measures, self-reported fitness, and self-esteem in the physical domain and self-reported MVLPA levels over 4 to 6 weeks following the diagnosis. These findings help to better understand the effect of cancer diagnosis on children's physical activity behavior.