Using heart rate to detect high-intensity efforts during professional soccer competition

The goal of this article is to detect, describe, and compare 2 heart rate (HR) conditions associated with high-intensity efforts but somewhat different in nature: The first one is indicated by HR values close to the maximum heart reserve (MHRR), and the second is indicated by a marked increase in the HR values (MIHR). It was expected that both conditions were associated with different game situations. A sample of 441 game situations (241 MIHRs and 200 MHRRs), taken from HR records and individual filming of 12 elite soccer players, was assessed along 7 preseason competition matches. The game situations in which each of these 441 HR conditions took place were identified, using a previously established taxonomy of a combination of field formats and category systems in the Match Vision Studio Premium. For the recording of the HR condition, an HRM Polar was attached to the players when in competition, together with a simultaneous filming of their performance during the game. The HRM and video recordings were synchronized beforehand to be able to relate the game situation in the film with HR conditions. The results showed significant differences between both HR conditions for 4 criteria of game situations (Ball in play, Game Center, Role, and Opposition). In all the cases, the MIHR is more associated with active participation of the players in the game, whereas the MHRR is more associated with the end of this participation. Thus, the results suggest that MIHR could be a useful complementary measurement to assess the intensity of physiological load that elite soccer players bear during competition, together with more traditional measurements such as MHRR.