Impact of exercise intensity during detraining on physical fitness and muscle functions in obese women post high-intensity interval training: A preliminary analysis

Background Regular physical exercise helps reduce body fat and improve obesity-related health issues by affecting various health indicators. However, 80% of individuals who intentionally lost weight experienced a rebound effect, commonly known as the yo-yo effect, within one year. Detraining, the cessation or reduction of exercise, can lead to rapid decreases in aerobic function and a decline in various physiological parameters. Objective This study aims to investigate whether varying exercise intensities during the detraining period can maintain improved body composition, physical fitness, and isokinetic muscle function in obese adult women after high-intensity interval training (HIIT). Methods Participants were divided into three groups: non-training (NTG, n = 6), low-intensity (LIG, n = 6), and moderate-intensity (MIG, n = 7) exercise groups. For eight weeks, the HIIT program was applied three times a week, followed by a four-week detraining period with varying exercise intensities. Body composition, physical fitness, and isokinetic muscle function were measured before and after the HIIT and detraining periods. Results Body composition, particularly waist circumference, hip circumference, and the waist-to-height ratio, significantly improved in the MIG compared to the control group. The MIG also positively affected muscular endurance, agility, and cardiorespiratory endurance. However, no positive effect on isokinetic muscle function was detected in any of the groups. Conclusions This study emphasizes the importance of continuous moderate-intensity exercise during the detraining period to maintain the anti-obesity effects of an 8-week HIIT program.