CARDIOVASCULAR RESPONSES TO MAXIMAL ISOKINETIC EXERCISE IN OLDER ADULTS

Abstract

Resistance exercise may counteract the sarcopenia associated with aging. The safety considerations of such exercise have not been fully determined. Previously, we have investigated cardiovascular responses to submaximal isokinetic resistance exercise. The purpose of the current study was to compare heart rate and blood pressure responses to maximal, typical isokinetic eccentric (ECC) and concentric (CON) resistance exercise protocols in healthy active older adults. In random order, subjects (n = 20, 74 ± 7y, 10 males) performed maximal ECC and CON isokinetic knee extension exercise (90° 3×10 reps, 5s rep rest, 2 min set rest). Heart rate (HR), and systolic (SBP) and diastolic (DBP) blood pressures were measured continuously and recorded every 15 seconds (Finapres). Mean arterial blood pressure [MAP; DBP+1/3(SBP-DBP)] and rate-pressure product (RPP; HRxSBP/100) were calculated. Mean ECC exercise torque (90 Nm) was significantly (p < .001) greater than mean CON exercise torque (59 Nm). HR, MAP, and RPP increased significantly (p < .001) in each set of ECC and CON exercise. Maximal CON exercise elicited greater (p < .01) increases in MAP and RPP than maximal ECC exercise despite the fact that ECC exercise was performed at a significantly greater torque output than CON exercise. These results may have implications for isokinetic training and rehabilitation programs for older adults.