Summer Youth Employment Programs for Health Promotion

Height and weight will be directly measured by trained staff. Each measurement will be taken twice, and the average will be used for analysis. Body mass index (BMI) will be calculated and expressed as Centers for Disease Control and Prevention (CDC) age- and sex-specific BMI-for-age z-scores (zBMI). The outcome will represent the change in zBMI from baseline to Week 6. A positive change score will indicate an increase (gain) in zBMI from baseline to Week 6, which will be considered a less favorable outcome. A negative change score will indicate a decrease in zBMI, which will be considered a favorable outcome. A change score of 0 will indicate no change in zBMI (maintenance), which will also be considered a favorable outcome for this intervention because preventing excess BMI gain during summer is a primary goal.

Sedentary behavior will be measured in minutes per day using a wrist-worn ActiGraph GT3X accelerometer on the non-dominant wrist over 8 consecutive days, including at least 2 valid weekdays and 1 valid weekend day. Activity intensities will be classified using cut points published by Hildebrand et al. The reported outcome will be the change in average daily sedentary behavior (minutes/day) from baseline to Week 6. A positive change score will indicate an increase in sedentary behavior, which will be considered an unfavorable outcome. A negative change score will indicate a decrease in sedentary behavior, which will be considered a favorable outcome. A change score of 0 will indicate no change in sedentary behavior (maintenance).

Moderate-to-vigorous physical activity (MVPA) will be measured in minutes per day using a wrist-worn ActiGraph GT3X accelerometer on the non-dominant wrist over 8 consecutive days, including at least 2 valid weekdays and 1 valid weekend day. Activity intensities will be classified using cut points published by Hildebrand et al. The reported outcome will be the change in average daily MVPA (minutes/day) from baseline to Week 6. A positive change score will indicate an increase in MVPA, which will be considered a favorable outcome. A negative change score will indicate a decrease in MVPA, which will be considered an unfavorable outcome. A change score of 0 will indicate no change in MVPA (maintenance), which will also be considered a favorable outcome.

Sleep duration will be measured in minutes per day using a wrist-worn ActiGraph GT3X accelerometer on the non-dominant wrist over 8 consecutive days, including at least 2 valid weekdays and 1 valid weekend day. Sleep duration will be estimated using the heuristic algorithm looking at the distribution of change in Z-Angle (HDCZA). The reported outcome will be the change in average daily sleep duration (minutes/day) from baseline to Week 6. A positive change score will indicate an increase in sleep duration, which will be considered a favorable outcome. A negative change score will indicate a decrease in sleep duration, which will be considered an unfavorable outcome. A change score of 0 will indicate no change in sleep duration (maintenance), which will also be considered a favorable outcome.

Screen time in hours and minutes (e.g., television, computer, video games, smart phones, tablets) will assessed via self-report during each 8-day behavioral assessment period. Screen time will be calculated as the average daily duration (minutes/day) by summing total reported screen time across completed daily logbooks and dividing by the number of valid diary days within each assessment period. The reported outcome will be the change in average daily screen time (minutes/day) from baseline to Week 6. A positive change score will indicate an increase in screen time, which will be considered an unfavorable outcome. A negative change score will indicate a decrease in screen time, which will be considered a favorable outcome. A change score of 0 will indicate no change in screen time (maintenance), which will also be considered a favorable outcome.

Dietary intake will be assessed using the NHANES 23-item Dietary Screener Questionnaire. Adolescents will self-report consumption of food and beverage items over the past day. For this outcome, unhealthy food items will include desserts, sugar-sweetened beverages, salty snacks, and fast food items. Responses will be used to estimate daily intake frequency (times/day) of unhealthy food consumption. The reported outcome will be the change in average daily frequency of unhealthy food intake (times/day) from baseline to Week 6. A positive change score will indicate an increase in unhealthy food intake, which will be considered an unfavorable outcome. A negative change score will indicate a decrease in unhealthy food intake, which will be considered a favorable outcome. A change score of 0 will indicate no change in unhealthy food intake (maintenance), which will also be considered a favorable outcome.

Recruitment capacity is the percentage meeting the recruitment goal.

Retention will be calculated as the percentage of enrolled participants who complete both baseline and post-intervention assessments for the primary outcome measures.

Fidelity will be assessed through weekly unannounced direct observations using a structured checklist developed by the research team specifically for the intervention. The checklist will assess key components of intervention implementation, including adherence, dose delivered, quality of delivery, and participant engagement. Each item will be rated using either binary scoring (0 = not implemented, 1 = implemented) or a 5-point Likert scale (1 = strongly disagree to 5 = strongly agree), depending on the construct. All domain scores will be standardized and converted to a percentage scale. Each intervention session will be independently rated by two trained researcher, and ratings will be averaged. Session-level fidelity scores will then be averaged across all observation weeks to produce a single fidelity score. The fidelity score will be expressed as a percentage, with higher scores indicating greater fidelity to the intervention protocol and lower scores indicating reduced fidelity.

Attendance will be calculated as the average number of days attended across total offered workdays, using employer time sheets.

Acceptability will be assessed using a quantitative satisfaction measure administered to adolescents following intervention participation. Participants will be asked to rate their likelihood of returning as a paid counselor the following summer on a scale ranging from 1 (not at all likely) to 10 (extremely likely). Individual responses will be averaged to generate a single acceptability score. The total score will range from 1 to 10, with higher scores indicating greater acceptability and willingness to participate again, and lower scores indicating lower acceptability. Scores closer to 10 will represent high acceptability, while scores closer to 1 will represent low acceptability of the intervention experience.

Dietary intake will be assessed using the NHANES 23-item Dietary Screener Questionnaire. Adolescents will self-report consumption of food and beverage items over the past day. For this outcome, healthy food items will include fruits, vegetables, 100% fruit juice, and milk items. Responses will be used to estimate daily intake frequency (times/day) of healthy food consumption. The reported outcome will be the change in average daily frequency of healthy food intake (times/day) from baseline to Week 6. A positive change score will indicate an increase in healthy food intake, which will be considered a favorable outcome. A negative change score will indicate a decrease in healthy food intake, which will be considered an unfavorable outcome. A change score of 0 will indicate no change in healthy food intake (maintenance), which will also be considered a favorable outcome.