BMI-stratified outcomes of a badminton training program on health-related fitness in adults with mild to moderate intellectual disabilities.

Background: Regular exercise, such as that obtained through badminton, can effectively improve health issues associated with insufficient physical activity among adults with intellectual disabilities (ID). However, there is a paucity of research exploring tailored interventions and post-exercise outcomes among adults with ID based on body mass index (BMI) stratifications. This study compared the effects of a 12-week badminton intervention on health-related physical fitness in adults with ID across three BMI levels, providing a theoretical reference for developing targeted exercise prescriptions for this population. Methods: In total, 60 adults (39 male and 21 female) 25-45 years of age with mild to moderate ID were included and allocated to one of three analysis groups based on their BMI (20 per group): normal weight (BMI: 18.5-24.99 kg/m²), overweight (BMI: 25.0-29.9 kg/m²), and obesity (BMI ≥30.0 kg/m²). A systematic 12-week badminton training intervention was conducted, with two 65-minute sessions per week. Health-related physical fitness assessments were performed before and after the intervention. Key outcome measures included (1) aerobic capacity (assessed using the 2-minute step test, resting heart rate, and vital capacity), (2) muscle strength and endurance (assessed through grip strength, standing long jump, sit-ups, and the 30-second chair stand test), and (3) flexibility and coordination (assessed via the sit and reach test, back scratch test, and timed up-and-go test). Data were analyzed using SPSS 22.0 for within-group and between-group comparisons. Results: Baseline health-related physical fitness indicators showed no significant differences among the normal weight, overweight, and obesity groups pre-intervention (p > 0.05). Completion of the badminton exercise program resulted in differential improvements. Significant enhancements were observed for all three groups in aerobic capacity (2-minute step test, resting heart rate, and vital capacity), muscle strength and endurance (right-hand grip strength, standing long jump, and 30-second chair stand test), and coordination (timed up-and-go test), after undergoing pre-and post-tests (p < 0.05). Multivariate analysis of variance (MANOVA) indicating differences between groups showed that compared with the overweight group, the normal weight group had greater improvements in right-hand grip strength; compared with the obesity group, the normal weight group exhibited greater improvements observed in right-hand grip strength and performance in the timed up-and-go test; and compared with the obesity group, the overweight group demonstrated more pronounced reductions in resting heart rate and better timed up-and-go test performance (p < 0.05). There was no significant change in flexibility (sit and reach test, back scratch test) between pre-test and post-test performances. MANOVA results for intergroup analyses showed no significant improvements in the 2-minute step test, lung capacity, left grip strength, sit-ups, standing long jump, sit and reach test, and back scratch test. Conclusion: Badminton exercise significantly improved aerobic capacity, muscle strength and endurance and coordination in adults with ID across all BMI categories. Core fitness indicators (right-hand grip strength, timed up-and-go test, and resting heart rate) exhibited a gradient improvement pattern: normal weight greater improvement than overweight, which was greater than obesity. Therefore, although badminton is an appropriate exercise intervention for adults with ID, BMI and BMI-related factors should be taken into consideration when designing personalized exercise programs to optimize training effects.