Exercise Strategy for Reducing Visceral Adipose Tissue in Community Residents With Obesity: A Sequential Multiple Assignment Randomized Trial

Background: Exercise is the most effective method of reducing visceral adipose tissue (VAT). However, the optimal exercise modality and strategy for reducing VAT have yet to be determined. PurposeThis study was designed to identify the optimal sequence exercise strategy for reducing VAT in community residents with obesity. Methods: A sequential multiple assignment randomized trial design was used to conduct a two-stage (8 weeks each) adaptive exercise for 40- to 64-year-old residents with obesity. In the first stage, the participants were randomly allocated into two groups, one of which did 30 minutes of moderate-intensity continuous training (MICT; n = 58) and the other which did 20 minutes of high-intensity interval training (HIIT; n = 58) three times per week. In the second stage, the nonresponders (with VAT decreases < 3%) were randomly reallocated into a group that performed MICT combined with an additional 10 minutes of resistance exercise or one that performed the opposite of the first-stage treatment (HIIT or MICT). Those who responded to the first-stage intervention (with VAT decreases of >= 3%) continued the same exercise treatment until 16 weeks. Results: The MICT intervention was found to be more efficacious than the HIIT intervention in reducing VAT during the first 8 weeks (beta = -4.10, p = .029). Among the nonresponders to MICT, the HIIT outperformed MICT combined with resistance exercise as the alternative choice in the second stage (beta = -7.36, p = .006). On the contrary, there were no significant differences between MICT and MICT combined with resistance exercise for the nonresponders to HIIT (beta = 1.34, p = .626). Those participants who repeated the same exercise modality (either MICT or HIIT) in both stages exhibited superior VAT reduction to those who changed exercise modalities after the first stage. Conclusions/Implications for Practice: The optimal sequence exercise strategy for reducing VAT is captured by a two-stage sequential multiple assignment randomized trial design. Community residents with obesity are advised to reduce VAT efficiently through participation in an 8-week MICT program. For those preferring HIIT rather than MICT, a 16-week program without changing the modality midway is recommended.