Assessment of the impacts of HIIT on frailty using multiple frailty assessment tools. The frailty status of SED and HIIT mice was assessed before and after the 8-week exercise phase using the Seldeen (A), Seldeen50 (B), Liu&Graber50 (C), Valencia score (D), C-FI (E), and FIAV (F) animal frailty assessment tools. Darker colors represent baseline and lighter colors endpoint for SED and HIIT, respectively. A “*” and “***” indicates a p < 0.05 and p < 0.001 in a paired t-test within groups, respectively. Higher scores are indicative of greater frailty in all scales except for FIAV (F).