Table 2.

Muscle volumes measured by magnetic resonance imaging (MRI) of left (exercising) and right (resting) knee extensors in young and old men

	Young men, muscle volume, cm3, mean ± s.d.		Old men, muscle volume, cm3, mean ± s.d.
	Left leg	Right leg	Left leg	Right leg
Knee extensors	1211 ± 107†	1194 ± 136†	848 ± 213	844 ± 177
Rectus femoris	198 ± 15*	192 ± 32*	110 ± 69	129 ± 47
Vastus lateralis	352 ± 75*	374 ± 62*	231 ± 44	294 ± 50
Vastus medialis	360 ± 75*	357 ± 79*	283 ± 98	224 ± 70
Vastus intermedius	300 ± 57*	271 ± 57*	223 ± 56	196 ± 47

Muscle volumes were greater in young men than in old men.

^*P < 0.05 and †P < 0.01 between young and old men.