High-intensity interval swimming improves cardiovascular endurance, while aquatic resistance training enhances muscular strength in older adults

The aim of this study was to examine the effects of free swimming (FS), aquatic resistance training (ART), and their combination (FS&ART) on the body composition, blood pressure, and physical fitness of older adults. The study employed a randomized controlled design, comparing three experimental groups with a control group. Eighty volunteers aged between sixty and seventy years (age: 66.2 ± 2.3 years; body mass index: 25.8 ± 4.3 kg/m²) participated in the 16-week intervention, consisting of two weekly sessions. Assessments were conducted at baseline and post-intervention, including anthropometric measurements, blood pressure readings, and the Senior Fitness Test. Significant differences were found between groups in post-intervention considering the chair stand test ( p = 0.017; ES = 0.125), arm curl test ( p = 0.029; ES = 0.111), 8-foot up and go test ( p = 0.042; ES = 0.102), and walk test − 6 min ( p = 0.005; ES = 0.156). Specifically, both ART (+ 20.1%; p