Heart rate (HR), mean arterial blood pressure (MAP), and rate-pressure product (RPP) responses to submaximal isokinetic concentric (CON) and eccentric (ECC) knee extension exercise were compared at the same absolute torque output in 20 young (mean+/-SD=23.2+/-1.7 years) and 20 older (mean+/-SD=75.2+/-4.6 years) adults. After determination of peak CON and ECC torques, subjects performed separate, randomly ordered, 2-minute bouts of isokinetic CON and ECC exercise (90 degrees/s, exercise intensity: 50% of CON peak torque). CON exercise elicited greater changes in HR, MAP, and RPP than ECC exercise (p<.001) for both age groups. There were no age-related differences in HR, MAP, or RPP responses for either CON or ECC exercise. At the same absolute torque output, isokinetic CON knee extension exercise elicited significantly greater increases in cardiovascular stress than ECC exercise in both young and older adults. This result has implications for determining appropriate fitness and rehabilitation programs.

Our purpose was to describe heart rate (HR), mean arterial blood pressure (MAP), and perceived exertion (RPE) responses to submaximal isokinetic concentric (CON) and eccentric (ECC) exercise at the same absolute torque output in older adults. Peak torques for ECC and CON knee extension were determined in healthy older males (n = 13) and females (n = 7). Subjects then performed separate, randomly ordered, 2-min bouts of CON and ECC exercise. Heart rate and MAP increased (p < .001) from resting values throughout both exercise bouts. CON exercise elicited a significantly greater cardiovascular response than ECC exercise after 60 s. Peak HR, MAP, and RPE after CON exercise were greater than after ECC exercise (p < .01). At the same absolute torque output, isokinetic CON knee extension exercise resulted in a significantly greater level of cardiovascular stress than ECC exercise. These results are relevant to resistance testing and exercise in older people.

1989 We compared heart rate (HR), mean arterial blood pressure (MAP) and rate-pressure product (RPP) responses to submaximal isokinetic concentric (CON) and eccentric (ECC) knee extension exercise at the same absolute torque output in 20 young (M&SD=23.2&1.7yr) and 20 older (M=75.2&4.6yr)adults. After determination of peak CON and ECC torques, subjects performed separate, randomly ordered, two-minute bouts of CON and ECC exercise at 90 degrees/s (exercise intensity = 50% of CON peak torque). Peak torques were higher (p<0.001) in ECC exercise, and were also higher (p<0.001) in younger vs. older adults for both CON and ECC exercise. HR, MAP, and RPP increased (p<.001) throughout the exercise bouts for both age groups. CON exercise elicited a greater HR, MAP, and RPP response than ECC exercise (p<0.001) for both age groups. There was no difference in peak HR or RPP between young and older adults for either type of contraction, however, peak MAP was higher in the older adults. Thus, at the same absolute torque output, isokinetic CON knee extension exercise elicited a significantly greater level of cardiovascular stress than ECC exercise in both young and old adults. These results have implications for determining appropriate fitness and rehabilitation programs for older adults. Supported by the Natural Sciences and Engineering Research Council