Fig. 3.

The effect of aging on MHC I (A) and MHC IIa (B) single fiber normalized power. Fiber type-specific normalized power comparisons were made to previous research from our lab using identical procedures. Data retrieved from young cross-country runners (n = 8M) (30); young healthy inactive (n = 12, 6F/6M) (67); middle age master's runners (n = 6M) and healthy inactive (n = 5M) (73); 80 yr old healthy (n = 6M) (61); 90 yr old healthy (n = 5, 3F/2M) (current study); SCI (n = 5M, 33 yr old) (45); Champion sprint runner (68). XC, cross-country; SCI, spinal cord injured.