Abstract
This study aimed to examine the interaction effect between the presence of heart failure and the degree of frailty on skeletal muscle mass index (SMI), handgrip strength, and 5 times sit-to-stand (5STS). This study revealed a significant interaction effect between the presence of heart failure and the degree of frailty on SMI, handgrip strength, and 5STS. The study results revealed that the combination of heart failure and frailty has synergistic negative effects on SMI and upper and lower limb muscle strength.