A271: High-intensity Interval Resistance Training on Physical Fitness and Body Composition in Overweight and Obese Adults

Abstract

In recent years, the prevalence of overweight and obesity has been steadily increasing in China. Finding an effective approach that can simultaneously improve cardiorespiratory fitness, increase muscle strength, and promote weight loss in overweight and obese individuals remains a significant challenge. This study investigates the effects of high-intensity interval resistance training (HIIRT) on optimizing body composition and promoting physical fitness. By improving training efficiency, the study aims to establish a scientific exercise intervention strategy to provide effective exercise guidance to support health management and weight control. A total of 26 untrained participants (BMI ≥ 24 kg/m²; body fat ≥ 25% for men and ≥ 30% for women) were recruited (age: 31.56 ± 8.98 years, height: 170.66 ± 10.76 cm, weight: 77.48 ± 23.02 kg). The intervention consisted of a two-week exercise adaptation phase followed by an eight-week HIIRT program. Body composition, maximal oxygen uptake (VO₂max), muscular strength, and resting metabolic rate were assessed using Metalyzer 3B and CORTEX Bike-M. Data were analyzed using SPSS and R software, and paired-sample t-tests were used to test the significance of differences before and after the intervention to evaluate the effects of HIIRT on strength, cardiopulmonary function, and body composition. Before the intervention, participants had a mean body weight of 77.48 ± 23.02 kg, a BMI of 26.22 ± 5.80 kg/m², a body fat percentage of 31.35 ± 6.68% and a maximum (6RM) squat of 55.4 ± 23.5 kg. After the intervention, body weight decreased significantly to 75.76 ± 4.53 kg, BMI to 25.63 ± 5.71 kg/m², and body fat percentage to 29.79 ± 6.92%, while 6RM squat increased significantly to 69.2 ± 22.20 kg (P \u3c 0.01). However, no significant differences in VO2max and resting metabolic rate were observed (P \u3e 0.05). 1) HIIRT effectively improves body composition and contributes to significant weight loss in overweight and obese individuals. 2) HIIRT significantly improved muscular strength. The effect of HIIRT on cardiorespiratory fitness requires further investigation, as the lack of improvement may be due to the specific interval time used in the training protocol. Similarly, the lack of significant changes in resting metabolic rate may be due to the weight loss during the intervention period