Table 5.

Single-muscle fiber quality in MHC I and IIa fibers of YE, LLE, and OH

	MHC I Fibers		MHC IIa Fibers
	Specific Tension, kN/m2	Normalized Power, W/L	Specific Tension, kN/m2	Normalized Power, W/L
YE	121 ± 2a	2.2 ± 0.1c,d	162 ± 3a	13.5 ± 0.5a
LLE	140 ± 3b	2.7 ± 0.1e	193 ± 3	18.5 ± 0.6
OH	131 ± 2	2.4 ± 0.1	191 ± 3	17.3 ± 0.5

Values are means ± SE. LLE, lifelong exercisers; MHC, myosin heavy chain; OH, old healthy nonexercisers; YE, young exercisers.

^aP < 0.05 vs. other groups;

^bP < 0.05 vs. OH;

^cP < 0.05 vs. LLE;

^dP = 0.055 vs. OH;

^eP = 0.057 vs. OH.