MHC composition of gastrocnemius and soleus muscles from 12-month-old WT (n = 6) and Neb-cKO mice (n = 6). A, Example of typical electrophoretic pattern of whole gastrocnemius muscle lysate (left) and MHC type composition (right). B, Example of typical electrophoretic pattern of whole soleus muscle lysate (left) and MHC type composition (right). Data are presented as percentage of total MHC. Values are mean ± SEM. ***P <0 .001, significantly different from WT mice. cKO, conditional knockout; MHC, myosin heavy chain; Neb-cKO, conditional nebulin knockout; Sol, soleus; TA, tibialis anterior; WT, wildtype