BACKGROUND:Obesity has become a global health issue,often accompanied by complications including obesity-related muscle atrophy.While exercise has been reported to improve various obesity-related diseases,there is limited research focusing on exercise modes. OBJECTIVE:To compare the effects of moderate-intensity continuous training(MICT)and high-intensity interval training(HIIT)on obesity-related muscle atrophy in mice under the premise of the same exercise distance,providing a scientific basis for exercise interventions for obesity-related muscle atrophy. METHODS:Seventy-two male C57BL/6 mice were divided into six groups(n=12 per group):standard chow diet,standard chow diet+MICT,standard chow diet+HIIT,high-fat diet,high-fat diet+MICT,and high-fat diet+HIIT.The study evaluated the effects of 8-week treadmill training with different exercise modes on long-term high-fat diet-induced muscle atrophy by detecting muscle mass,muscle index,muscle fiber cross-sectional area,muscle lipid deposition,and the expression of muscle atrophy marker genes Murf-1 and Atrogin-1 in the gastrocnemius muscle of mice exposed to long-term high-fat diet. RESULTS AND CONCLUSION:Compared to the high-fat diet group,both MICT and HIIT improved the decrease in gastrocnemius muscle index(MICT+18.8%vs.HIIT+17.6%,not significant between the two modes),muscle fiber atrophy(MICT+15.5%vs.HIIT+13.7%,not significant between the two modes),and muscle lipid deposition(MICT-19.8%vs.HIIT-17.1%,not significant between the two modes).At the gene level,compared with the high-fat diet group,both MICT and HIIT could significantly down-regulate the expression of Murf-1(MICT-62.4%vs.HIIT-52.6%,the down-regulation caused by MICT was significantly greater than that by HIIT;P＜0.01)and Atrogin-1(MICT-43.3%vs.HIIT-29.8%,the down-regulation caused by MICT was significantly greater than that by HIIT;P＜0.01).Based on exercise mode comfort and genetic evidence,MICT mode might be more suitable for exercise interventions in obesity-related muscle atrophy.