Self-efficacy, physical activity, and aerobic fitness in middle school children: Examination of a pedometer intervention program.

摘要

The purpose of this study was to examine the relationships among self-efficacy levels, physical activity, aerobic fitness, and body composition (relative body mass index; RBMI) and to determine whether a school-based pedometer intervention program would improve those variables and prevent weight gain in sixth and seventh graders in rural mid-South middle schools. Bandura's Social Cognitive Theory served as the theoretical basis for the study. Methods. A quasi-experimental pre-test, post-test design was used. The sample, recruited from two rural middle schools in Kentucky, consisted of 116 sixth and seventh grade students (98% Caucasian, 51% male, age=11.65+/-0.71). Anthropometric assessment of height, weight, body mass index (BMI), BMI percentile ranges, and RBMI were conducted. Physical activity levels were assessed using Digiwalker 200 pedometers and aerobic fitness levels were assessed using the one mile walk test. The Physical Activity Self-Efficacy scale was used to measure self-efficacy levels in participants and parental support of physical activity was assessed using the Amherst Health and Activity Survey. The intervention program consisted of students wearing a pedometer during the school day and participating in 10 minutes of physical activity beyond their usual activities at school. Data were analyzed using descriptive statistics, Pearson's correlation coefficient, and repeated measures ANOVA. Results. Aggregate baseline data revealed a mean self-efficacy score of 14.9; physical activity level of 10181.41 steps/day; aerobic fitness level (VO2max) of 49.4 ml/kg/min, BMI of 21.84, with 56.9% of students classified in the healthy weight range, 13.8% as overweight, and 29.3% as obese. Only 19% of students meet recommended physical activity levels. Weakly positive correlations between self-efficacy and physical activity (r = 0.269, p = 0.004) and self-efficacy and aerobic fitness (r = 0.236, p = 0.013) were found. A weakly correlated inverse relationship was revealed between self-efficacy and RBMI (r = -0.243, p = 0.009). Physical activity was weakly correlated with aerobic fitness (r = 0.309, p = 0.001), while a weak, negative correlation was found between physical activity and RBMI (r = -0.361, p = 0.000). Finally, aerobic fitness was weakly, inversely correlated with RBMI (r = -0.493, p = 0.000). Students in the intervention school (n=55) were similar in ethnicity, gender, and age to the control group (n=61). Physical education (PE) class participation was found to be a confounding variable in the study resulting in subgroup analysis of pre-post differences in outcome measures based on concomitant PE. There were no statistical differences between the intervention and control groups and between subjects within groups when analyzing outcome variables. Both groups exhibited a non-significant decrease in physical activity over the course of the study. Although not statistically significant, the intervention group had greater improvements in self-efficacy, aerobic fitness levels, and RBMI than the control group. Conclusion. These study results support the findings from other research regarding the high prevalence of overweight and low levels of physical activity in rural children. The use of the pedometers to promote physical activity, fitness, and self-efficacy proved to be a cost effective, easy to implement method. Additional research focusing on increasing diversity and sample size is warranted.