a, Time spent balanced during a fixed speed rotarod test for 18-month-old ATTAC mice (n = 6 male and 8 female mice per group). b, Novel object investigation test. The percent of investigations of a novel object divided by the total investigations is graphed. Key and animal numbers are as indicated in a. c–e, Time-to-exhaustion (c), distance (d) and work (e) during a treadmill exercise test. Animal numbers are as indicated in c. f, Gastrocnemius muscle weight of ATTAC mice (n = 6 12-month-old males and females; n= 4 18-month-old –AP males and females; n = 4 18-month-old +AP males and females). g–i, Myofiber diameter measurements on isolated gastrocnemius (g), abdominal (h), and paraspinal muscle (i). Animal numbers are as indicated in f. j, Analysis of forelimb grip strength of ATTAC mice. Legends in d–j are as in c. Error bars indicate s.e.m. Unpaired two-tailed t tests were used to determine statistical significance. *, P<0.05; **, P<0.01; ***, P<0.001.