Triceps surae muscle power, volume, and quality in older versus younger healthy men

This study investigated whether loss of power with aging is fully accounted for by a decrease in muscle volume. Triceps surae power and volume (VOL) were measured in 18 older (OM: 69-82 years) and 12 younger men (YM: 19-35 years). Isokinetic peak torque was measured to determine torque-velocity and power-velocity relationships. Both peak power observed (PPobs) and peak power estimated from Hill's equation (PPest) were markedly reduced in the OM (PPobs was 45% and PPest was 43% of those of the YM). VOL was 81% of that of the YM (p < .001). Specific power (PPest/VOL) of the OM was 55.2% of that of the YM (p < .001). Torque at PPest accounted for a greater proportion of the decline in PPest in the OM than did optimum velocity (50% vs 13%, respectively). Hence, the present results showed that only approximately half of the loss in triceps surae peak power in old age is due to decreases in muscle VOL. Copyright 2005 by The Gerontological Society of America.