Aerobic exercise in adolescents with obesity: preliminary evaluation of a modular training program and the modified shuttle test.

Background: Increasing activity levels in adolescents with obesity requires the development of exercise programs that are both attractive to adolescents and easily reproducible. The aim of this study was to develop a modular aerobic training program for adolescents with severe obesity, with a focus on variety, individual targets and acquiring physical skills. We report here the effects on aerobic fitness from a pilot study. Furthermore, we examined the feasibility of the modified shuttle test (MST) as an outcome parameter for aerobic fitness in adolescents with severe obesity.

Methods: Fifteen adolescents from an inpatient body weight management program participated in the aerobic training study (age 14.7 +/- 2.1 yrs, body mass index 37.4 +/- 3.5). The subjects trained three days per week for 12 weeks, with each session lasting 30-60 minutes. The modular training program consisted of indoor, outdoor and swimming activities. Feasibility of the MST was studied by assessing construct validity, test-retest reliability and sensitivity to change.

Results: Comparing pretraining and end of training period showed large clinically relevant and significant improvements for all aerobic indices: e.g. VO2 peak 17.5%, effect size (ES) 2.4; Wmax 8%, ES 0.8. In addition, a significant improvement was found for the efficiency of the cardiovascular system as assessed by the oxygen pulse (15.8%, ES 1.6). Construct validity, test-retest reliability and sensitivity to change of the MST were very good. MST was significantly correlated with VO2 peak (r = 0.79) and Wmax (r = 0.84) but not with anthropometric measures. The MST walking distance improved significantly by 32.5%, ES 2.5. The attendance rate at the exercise sessions was excellent.

Conclusion: This modular, varied aerobic training program has clinically relevant effects on aerobic performance in adolescents with severe obesity. The added value of our aerobic training program for body weight management programs for adolescents with severe obesity should be studied with a randomized trial. This study further demonstrated that the MST is a reliable, sensitive and easy to administer outcome measure for aerobic fitness in adolescent body weight management trials.