Fig. 1.

A: mass of the tibialis anterior muscle in young and old mice. Data are presented as means ± SE. *P < 0.05 compared with values from young animals, n = 50–59. B: example of transverse sections from muscles of young (i) and old (ii) mice stained with hematoxylin and eosin. C: cross-sectional area of single fibers obtained from the flexor digitorum brevis (FDB) muscle of young and old mice. Data are presented as means ± SE. *P < 0.05 compared with values from young animals, n = 100 fibers.