Heart rate and blood lactate in 400 m flat and 400 m hurdle running: a comparative study.

This study was conducted on a group of male sprinters (n e S) to compare heart rate (HR) and blood lactate (La) response in 400 m flat and 400 m hurdle running during weekly trial race. Durations of the flat and hurdle races were 51.65 ± 1.51 and 58.27 ± 1.97 sec respectively. Peak HR attained at the end of the flat and hurdle races were 192.4 ± 5.3 and 193.6 ± 4.1 beats/min, whereas, average HR during the events were 173.6±22.6 and 176.7±19.6 beats/min respectively. La level following the flat event (18.84 ± 1.57 mmollL) was found significantly (P<0.05) higher than the post-hurdle race (16.14 ± 1.97 mmol/L). The study indicates that cardiovascular stress is similar in both the events although flat race impose higher anaerobic glycolytic demand than hurdle run.