Effects of a wearable-based intervention in overweight and obese adolescents: A randomized controlled trial considering gender, baseline activity, and intervention exposure

Abstract

The objectives of the present study were (a) to determine the effects of a 12-week intervention using wearables promoted through physical education classes on physical activity, body composition, physical fitness and psychological well-being of overweight or obese adolescents; and (b) to analyze the differences in outcomes based on gender and baseline physical activity. Seventy-three overweight and obese adolescents (mean age: 13.44 ± 1.12 years) were randomly assigned to an experimental group (EG) or control group (CG). The EG used a physical activity wearable for 12 weeks. Both groups were assessed before and after the intervention. Regarding primary outcomes, the EG showed an increase in physical activity (p = 0.048) and reductions in body mass index (p = 0.007), fat mass (p < 0.001), and sum of 3 skinfolds (p = 0.002), with moderate-to-large effect sizes (η2 > 0.09). According to the secondary outcomes, improvements in physical fitness were limited, with increases observed only in abdominal muscular endurance, and these changes were also present in the CG. Subgroup analyses showed that females and adolescents with low baseline physical activity experienced greater benefits, particularly in fat-related variables (p < 0.001–0.037), with large effect sizes (η2 > 0.14). Additionally, adolescents with greater exposure to the wearable-based intervention showed more consistent improvements in fat-related outcomes (p < 0.001–0.032), with large effect sizes (η2 > 0.25). In conclusion, a wearable-based intervention promoted through physical education classes may contribute to meaningful improvements in body composition, particularly among females and previously inactive adolescents who are overweight or obese. However, effects on physical fitness and psychological well-being were limited, highlighting the importance of intervention design, adherence, and complementary motivational strategies.