Abstract

Anticipatory cardiac responses to two running events were investigated from the electrocardiogram recorded by a telemetry system in 13 male varsity trackmen and 3 untrained subjects. The track events studied were the 30 m dash as a sprint and 1,200 m run as an endurance run. 1) In the 30 m dash, the R-R intervals shortened prior to exercise represented 22-45 of the resting R-R intervals after warm-up (control value) in trained runners and 13-16 in untrained runners. The R-R intervals shortened during exercise represented 0-23 of the control value in trained runners and 37-38 in untrained runners. 2) In the 1,200 m run, the R-R intervals shortened prior to exercise represented 14-41 of the control value in trained runners and 21-27 in untrained runners. The R-R intervals shortened during exercise represented 24-43 of the control value in trained runners and 40-45 in untrained runners. 3) It is suggested that performance in sprinting depends on the anticipatory cardiac response controlled by feedforward signals from the central nervous system, whereas performance in endurance running depends on cardias regulation by feedback signals from baroreceptors and muscle receptors during exercise.