The X-linked dystrophic animal model, the mdx mouse, shows an extraordinary capacity for sustained muscle regeneration compared with X-linked dystrophic golden retriever dogs and humans with Duchenne muscular dystrophy. To test the hypothesis that muscles of mdx mice might have inherently superior muscle regeneration to that in nondystrophic animals, muscle regeneration in response to a crush injury was examined in mdx mice and in the nondystrophic, parental strain C57Bl/10Sn. Autoradiographic techniques were used specifically to investigate the timing of muscle precursor replication after crush injury. Little difference in the regenerative capacity, either histologically or with respect to the timing of muscle precursor replication, was found between mdx mice and C57Bl/10Sn or other nondystrophic strains of mice.