Based on pilot data for the primary outcome (i.e., CTSIB), we conducted a power analysis of the required sample size to test the difference between the experimental and controls groups at the post-intervention measurement occasion (i.e., objective 1). The pilot data showed a standardized effect size of 0.80. Assuming the number of model covariates to be 3, the proportion of variance explained by these covariates to be 10%, and a two-tailed test of the null hypothesis of no group difference at p = .05, a sample size of 46 is required. We expect an attrition rate of 20% over the study observation period for objective 2. Given this, we propose to recruit a sample of N = 56 individuals to participate, with equal numbers to be recruited to the treatment and control groups.