The effects of interval training on oxygen pulse and performance in supra-threshold runs.

The aim of this study was to examine (i) the effects of a severe interval training period on oxygen pulse kinetics (O2-p, the ratio between VO2 and heart rate), and (ii) to study the consequences of these effects on the variation of performance (time to exhaustion) during severe runs. Seven athletes were tested before and after an eight-weeks period of a specific intermittent training at v Delta 50, i.e., the intermediate velocity between the lactate threshold (vLT) and the velocity associated with VO2max (vVO2max ). During the test sessions, athletes performed an incremental test and an all-out test at the pretraining v Delta 50. After the training period they also completed an additional all-out test at the posttraining v Delta 50 (v Delta 50bis). Results showed that after training there was i) an increase in the O2-p maximal value during the incremental test (22.7 +/- 1.5 mlO2.b-1 vs. 20.6 +/- 1.5 mlO2.b-1; p < 0.04), ii) a decrease in the time to reach the O2-p steady state (TRO2-p ) at the same absolute v Delta 50 (33 +/- 7 s vs. 60 +/- 27 s; p < 0.04) and iii) an increase in the O2-p steady state duration (TSSO2-p) at the same absolute v Delta 50 (552 +/- 201 s vs. 407 +/- 106 s; p < 0.04). However, there was no relationship between the improvement of these two O 2 -p kinetics parameters (TRO2-p and TSS O2-p) and those of the performance. This study found that after an individualised interval-training program conducted at the same absolute velocity, the O2-p kinetics reached a steady state quicker and for a longer duration than before training. This is however not related with the improvement of performance.