People tend to avoid activities that they believe exceed their coping capabilities, but they readily undertake activities and select social environments they judge themselves capable of handling.
A school nurse was also involved in classroom activities related to promoting healthy lifestyles. The nutritionist and school nurse were in charge of answering questions related to diet control and the exercise program. Social skills for interpersonal relationships and psychological counseling due to weight control and body image change were also provided as part of the classroom activity. Various play activities and games were designed to encourage interactive sharing; positive feedback and reward systems were also provided to enhance self-efficacy as shown in figure 1. For example, adolescents learned how to select healthy meals and got involved in practice sessions about options and choices related to low-sugar and low-fat foods. In addition, each adolescent was also encouraged before the interventions to set realistic goals to help improve their dietary behavior and physical activity levels; they then wrote these down and sealed them in an envelope. The submission of the weekly dietary log book and participation in the daily after-school planned physical activity served as a tracking system to monitor each adolescent’s progress. The log book enabled the researchers to track the frequency and usage duration of different sessions. These would be used in future analyses to validate the relations between self-regulatory skills and changes in self-efficacy after the expected behavioral change.
The individual and group behavior change initiatives aimed to promote the adoption of healthy behaviors and incorporate them into various behavior modification strategies: self monitoring, goal setting, group competition, and reinforcement through social recognition and rewards. Self monitoring and goal setting occurred throughout in order to reinforce and encourage adolescents to learn self-regulatory skills that are essential for behaviour change in social environments. During each social activity, the adolescents were asked to refer back to prior goal-setting and self-monitoring activities so as to reinforce these skills and foster repeated practice. Targeted behaviors were reinforced by a special recognition and reward system during regular gatherings in the support group.
Design
A quasi-experimental study design was adopted, with an intervention group and a control group with pre- and post-tests using the Chinese versions of the following scales: Weight Efficacy Lifestyle Scale, Nutritional Self-efficacy Scale, Exercise Self-efficacy Scales, Psychosocial Functional Domain, Adolescent Lifestyle Questionnaire and Body Shape Scale. Figure 2 shows the data collection procedure from the four primary schools in a suburban area of Hong Kong from which students were recruited and assigned to intervention and control groups.
Anthropometric measurements included height (m), weight (kg) and blood pressure (mmHg). Questionnaires were distributed to all adolescents (N=120) who attended the school in Primary 4-6. There were 119 questionnaires that were completed and returned, as one participant dropped out of the intervention group. As a result, 119 (response rate 99.1%) questionnaires were analysed for this study. Altogether we recruited 119 overweight (BMI ≥ 85th to 94th percentile of age) and obese adolescents (BMI ≥ 95th percentile of age) studying in Primary 4-6 and aged 10-13, with BMI at or above the 85th percentile. They were recruited equally from the four participating primary schools, with 30 from each school. Thus 59 overweight and obese adolescents from two of the primary schools were assigned to attend the 6-month efficacy-enhancing weight loss intervention. The 60 overweight and obese adolescents in the other two primary schools were assigned as the