Effects of dysferlin and dystrophin deficiencies on skeletal muscle contractile properties. We investigated the extensor digitorum longus (EDL) muscles taken from WT (n = 4), dysferlin-null (n = 6), mdx (n = 8) and DKO mice (n = 3). (A) Tetanic force measurements prior to LC. *P < 0.05 and **P < 0.01. (B) Tetanic force recovery following LC. Dysferlin deficiency had a significant effect on force recovery in the absence of dystrophin, as indicated by a significant interaction (P = 0.04) between dysferlin, dystrophin and time after LC on the basis of analysis of variance. (C) Summary of estimated maximal recovery levels following LC. *P < 0.05. (D) Summary of force recovery rate following LC. *P < 0.05.