Physical training improves insulin resistance syndrome markers in obese adolescents

Introduction: The purpose of this study was to test the hypothesis that physical training (PT), especially high-intensity PT, would have a favorable effect on components of the insulin resistance syndrome (IRS) in obese adolescents. Methods: Obese 13- to 16-yr-olds (N = 80) were randomly assigned to one of the following 8-month interventions; 1) lifestyle education (LSE)-alone every 2 wk, 2) LSE+moderate-intensity PT, and 3) LSE+high-intensity PT. PT was offered 5 d·wk^-1. Plasma triacylglycerol (TAG), total cholesterol (TC), high-density lipoprotein cholesterol (HDLC), very low-density lipoprotein cholesterol (VLDLC), low-density lipoprotein cholesterol (LDLC), low-density lipoprotein (low density lipoprotein (LDL)) particle size, apolipoproteins AI and B, glucose, insulin, and blood pressure were measured with standardized methods. Results: The intent-to-treat analyses for all subjects who completed preand post-tests regardless of their adherence to the interventions showed that the LSE+high-intensity PT group had more favorable changes than the LSE-alone group in TAG level (P = 0.012), TC/HDLC (P = 0.013), and diastolic blood pressure (P = 0.031). For efficacy analyses, all PT subjects who attended at least 2 d·wk^-1 (40%) were combined into one group (LSE+PT) and compared with the LSE-alone group. These two-group analyses showed significant interactions (P < 0.001) between baseline values and group membership for ΔTAG, ΔVLDLC, and ΔTC/HDLC, such that subjects who had the least favorable baseline values showed the most beneficial impact of the PT. Of particular interest was a favorable effect of the PT on LDL particle size. Conclusion: PT, especially high-intensity PT, had a favorable effect on several IRS markers in obese adolescents.