Impact of combined aerobic–resistance exercise training without dietary intervention on irisin serum levels in overweight and obese girls

Abstract

Problem Statement. Obesity is a major threat to public health across the world. The progressive trend of overweight is serious among the children and adolescents. Physical activity is a useful way of proper development of the young adolescents. Irisin, a hormone secreted by skeletal muscle, protects body against the side effects of obesity such as increased body weight and insulin resistance. Purpose.This semi-experimental research aimed to investigate the impact of an 8 week combined exercise training program on specific physical fitness factors, as well as on the serum levels of irisin and insulin resistance in children classified as obese or overweight. Materials and methods. Twenty female students classified as obese or overweight (mean age: 10.85 ± 1.03 years, weight: 49.07 ± 9.64 kg, BMI: 23.25 ± 2.73 kg/m2) were selected using convenience (availability) sampling and subsequently randomized into two groups: intervention and control. The intervention group underwent an 8-week program consisting of combined resistance–aerobic exercise training (with a 3:2 ratio on alternate days), totaling five sessions per week. Conversely, the control group adhered to their regular daily routines. Baseline and post-training assessments included measurements of anthropometric and physical fitness indices. Blood samples were collected 24 h before and after the intervention. To analyze the data, Shapiro–Wilk tests assessed normality, RM-ANOVA examined intragroup changes, and ANCOVA tests evaluated intergroup differences, with a statistical significance level set at p ≤ 0.05. Results. The inferential analysis unveiled a significant difference between the two groups, specifically in insulin resistance, lower-body and static strength, VO2max, and dynamic balance. However, no significant disparities were observed in irisin levels, lower-body explosive power, upper body strength, BMI, weight, fat percentage, and fat-free mass. Notably, irisin levels exhibited a significant increase within the intervention group. Conclusions. This study shows that a combined aerobic (rope skipping)–resistance exercise training regimen holds promise for enhancing selected physical fitness indices. Additionally, this exercise modality significantly reduces insulin resistance in obese and overweight children.