. 2014 Aug 10;36(4):9699. doi: 10.1007/s11357-014-9699-z

Table 4.

Muscle fiber distribution and fiber area

	Fiber type	Young	Old
Fiber circularity	I	0.77 ± 0.01	0.75 ± 0.01
Fiber circularity	II	0.77 ± 0.01	0.72 ± 0.01
Fiber type distribution (fiber%)	I	51 ± 3	56 ± 5
Fiber type distribution (fiber%)	II	49 ± 3	44 ± 5
Fiber type distribution (CSA%)	I	47 ± 4	57 ± 4
Fiber type distribution (CSA%)	II	53 ± 4	43 ± 4
Muscle fiber CSA (μm²)	I	6316 ± 486	6566 ± 364
Muscle fiber CSA (μm²)	II	7584 ± 390^#	5574 ± 371^#*

Data represent means ± SEM

CSA cross-sectional area. ^#: Significantly different compared with type I muscle fibers (P < 0.05). *: Significantly different compared with young (P < 0.05)