Transition points of heart rate during a progressive maximal intermittent field test in young soccer players

Abstract

The purpose of this study was to identify the heart rate inflection point (HRIP) and the heart rate deflection point (HRDP) during a progressive maximal intermittent field test (TCar) in the 29 young soccer players. In order to identify the transition points, the differences of the heart rate (HR) values derived from linear and polynomial fits using all HR points were calculated. We were able to identify the HRIP in just three subjects (76 ± 1% of HR max and 77 ± 2% of Peak Velocity). The HRDP was identified in all the subjects (92% ± 2% of HR max and 84 ± 4% of Peak Velocity). The reduced number of identifications for HRIP was probably due the elevated values of HR in the first stage of TCar (149 ± 12 beats·min-1 ). Thus, using the original TCar protocol, it is possible to identify the HRDP. However, for studies using HRIP, it should be used with a smaller initial load in the test.