Effects of home-based Thai-boxing high-intensity interval training on physical fitness and body composition in sedentary young adults: A six-week randomized controlled trial

BACKGROUND: Sedentary behavior in young adults increases cardiovascular risk. High-intensity interval training (HIIT) improves cardiometabolic health, yet Thai-boxing HIIT (TB-HIIT) remains underexplored. This study examined the effects of home-based TB-HIIT on physical fitness and body composition in sedentary young adults. MATERIALS AND METHODS: Fifty-eight participants were randomly assigned equally to either a 6-week TB-HIIT group or a control group (CG). The TB-HIIT group completed eight 60-second instructional bouts at high intensity, interspersed with 60-second active recovery. The CG received general health education combined with strengthening and moderate-intensity exercise. Both groups followed their respective home-based programs for 6 weeks. Physical fitness outcomes (V̇O 2 max, resting blood pressure, resting heart rate, handgrip strength, trunk endurance) and body composition were assessed at baseline, week 3, and week 6. RESULTS: At 6 weeks, the TB-HIIT demonstrated significantly greater improvements in V̇O 2 max than the CG ( P = 0.001). TB-HIIT also produced larger reductions in resting systolic ( P = 0.02) and diastolic blood pressure ( P = 0.03), mean arterial pressure ( P = 0.003), and resting heart rate ( P = 0.003). Superior gains were observed in handgrip strength ( P = 0.03) and trunk endurance ( P = 0.01). Significant reductions in fat mass ( P = 0.009) and body fat percentage ( P = 0.04) were noted. No significant between-group differences were found for muscle mass or fat-free mass ( P > 0.05), although both improved within the TB-HIIT group. CONCLUSION: A 6-week home-based TB-HIIT program is an effective intervention for improving physical fitness and body composition in sedentary young adults.