Sample size calculation
We calculated sample size based on the assumption that patients who received a behavior-change intervention improved the primary outcome (physical activity levle). Sample size was calculated using the formula: n1 = n2 = (Zα + Zβ)2 * 2σ2/δ2. The two-group sample size ratio was 1:1, statistical power of 90%, and a 2-sided significance level of 0.05. According to the pilot study, σ = 210.56 and δ = 154.08 were substituted into the formula. Allowing for an 15% loss to follow-up, we planned to recruit 92 participants (46 per group).