We examined the effects of 12 wk of dynamic strength training on the heart rate (HR) and blood pressure of older male subjects during 10 repetitions of single-arm curl and single- and double-leg press at 60 and 80% of both the pre- and posttraining maximum capacities and during single maximum lifts (1 RM). The circulatory responses were greater at 80% of 1 RM than at 60% and increased with active muscle mass. After training, the 1 RMs increased by 24 (legs) to 54% (arms) and there was a marked attenuation of HR and arterial pressure during exercise when subjects lifted the same absolute load. Greatest reductions in HR (108 +/- 4 to 94 +/- 2 beats/min), systolic blood pressure (BPs, 247 +/- 14 to 206 +/- 9 Torr), diastolic pressure (156 +/- 9 to 116 +/- 5 Torr), mean arterial pressure (143 +/- 6 to 131 +/- 5 Torr), and rate-pressure product (268 +/- 22 to 196 +/- 12 HR.BPs/100) occurred during double-leg press at 80% of the pretraining 1 RM. After training, during lifting at 60, 80, and 100% of the posttraining 1 RMs, the HRs and arterial pressures were the same as those during pretraining testing when the same relative, but lighter, absolute loads were used. These observations are consistent with a significant part of the circulatory response to weight lifting being mediated by a feedforward "central command" mechanism coupled to the relative intensity rather than to the absolute level of force.