Relationship between Oxygen Uptake Reserve and Heart Rate Reserve in Young Male Tennis Players: Implications for Physical Fitness Monitoring.

The aims of this study were to (i) verify the relationship between reserve oxygen uptake (VO reserve ) and reserve heart rate (HR reserve ) in young male tennis players, and (ii) understand the relationship between oxygen uptake (VO 2 ) measured at the end of a tennis drill and recovery heart rate (HR recovery ) after the tennis drill. Ten young male tennis players (16.64 ± 1.69 years; 62.36 ± 6.53 kg of body mass; 175.91 ± 5.26 cm of height) were recruited from the National Tennis Association. Players were instructed to perform a tennis drill based on an incremental intensity protocol. Afterward, three levels of intensity were used based on VO 2reserve and HR reserve . A significant variance was observed between levels (VO 2reserve and HR reserve = p < 0.001). VO 2reserve presented a significant and high agreement with HR reserve . The mean data revealed non-significant differences ( p > 0.05), a very high relationship of linear regression (R 2 = 82.4%, p < 0.001), and high agreement in Bland Altman plots. VO 2, at the highest level of intensity (>93%), presented a significant correlation with HR recovery during the immediate 30 s after the drill (r s = 0.468, p = 0.028). Tennis coaches or instructors must be aware of the differences between monitoring or prescribing training intensities based on HR reserve or HR max . They can also use HR recovery for 30 s immediately after exercise to verify and understand the variation in their players' cardiorespiratory capacities.