Fig. 5

Characterization of top male-specific differentially expressed genes and mitochondrial content in the fittest vs. weakest older adults of both sexes. A Top 15 male-specific differentially expressed genes. Blue color indicates a decreased gene expression and red color indicates a higher gene expression in the weakest compared to the fittest groups. B Representative pictures of COX4 immunostaining in vastus lateralis muscle tissue (100 × magnification). C Correlation between the average length of mitochondrial branches and PRKN expression (normalized RNA-seq counts) using datapoints from all samples from male older adults with myofibers cut in longitudinal direction (n = 20). D Gene expression of PRKN (normalized RNA-seq counts) in the fittest and weakest groups of both sexes. All data were normally distributed. Values represent mean ± SEM, ***p < 0.01