Racial and sex differences in strength, peak power, movement velocity, and functional ability in middle aged and older adults

Abstract

To determine sex and race differences in strength, muscle power, movement velocity, and functional ability, knee extensor strength and muscle power normalized for muscle volume was measured in 79 middle-aged and older adults (30 men and 49 women, age range 50-85 yrs). Results indicated that men had 55% greater muscle volume (MV; P < 0.001), 24% greater 1 RM strength (P < 0.01), 9% greater muscle quality (MQ; 1 RM/MV; P < 0.05), 26% greater peak muscle power (PP; P < 0.01), and 14% greater MPQ (PP/MV; P < 0.001) than women. However, women displayed a 38% faster peak movement velocity than men when expressed per unit of muscle (movement velocity quality) (PV/MV; P < 0.001). Race analysis showed that African Americans had 20% greater MV than Caucasians (P < 0.001), but 11% lower MQ (P < 0.01) and a 17% lower PV/MV (P < 0.05) than Caucasians of similar age. Men displayed a 22% faster stair climb time than women, while Caucasians exhibited 19% and 16% faster times in rapid pace gait and 8-ft up-and-go, respectively. Thus, despite greater strength and power per unit of muscle in men, women have a faster knee movement velocity per unit of muscle than men. Moreover, African Americans have greater knee extensor muscle volume than Caucasians, but exhibit lower muscle quality and movement velocity quality.