Mice lacking dysferlin (Dysf) serve as a model of Limb Girdle Muscular Dystrophy type 2B, and loss of dysferlin induces muscular dystrophy by impairing muscle repair. (A) Weekly prednisone exposure mitigated loss of grip strength over time seen in this model, and treatment increased muscle force at study endpoint (Tibialis anterior). (B and C) Weekly prednisone–treated mice had improved respiratory and cardiac muscle function over time, as compared with vehicle-treated controls. (D) ATP levels were increased in both muscle and heart tissues at endpoint. Curves, mean ± SEM; histograms depict single values and mean ± SEM; n = 10 mice/group. *P < 0.05 vs vehicle, Welch’s t-test (two-tailed); #P < 0.05 vs vehicle, 2-way ANOVA.