. Author manuscript; available in PMC: 2013 Jul 1.

Published in final edited form as: Muscle Nerve. 2012 May 29;46(1):51–59. doi: 10.1002/mus.23266

Table 1.

Muscle fiber cross-sectional area (CSA) and fiber type distribution at baseline.

	Young Men	Young Women	Older Men	Older Women
Muscle fiber CSA, μm² ^*
Type I	3,964 ± 462^a^,^b	3,652 ± 499^a^,^b	4,725 ± 462^b	3,741 ± 499^a^,^b
Type II	6,098 ± 462^c	3,265 ± 499^a	4,389 ± 462^a^,^b	3,513 ± 499^a^,^b
Fiber distribution, % ^† ^□
Type I	33.9 ± 3.8^x	44.8 ± 4.1^x^,^y	46.1 ± 3.8^y	48.7 ± 4.1^y
Type II	66.1 ± 3.8^z	55.2 ± 4.1^y	53.9 ± 3.8^y	51.3 ± 4.1^y

Values are means ± SEM.

^a,b,c

Means in rows for type I and type II CSA not bearing a common superscript differ, P< 0.05

^x,y,z

Means in rows for type I and type II % not bearing a common superscript differ, P< 0.05

Main effect of gender, P< 0.05

^†

Gender × fiber type interaction, P< 0.05

^□

Age × fiber type interaction, P< 0.05