Tracking Changes in Maximal Oxygen Consumption with the Heart Rate Index in Female Collegiate Soccer Players

The purpose of this study was to determine if the HRindex Method (VO2max = [6 x HRindex – 5] x 3.5, where HRindex = HRmax/HRrest) was accurate for tracking changes in VO2max following 8‐weeks of endurance training among collegiate female soccer players. Predicted VO2max via the HRindex Method and observed VO2max from a maximal exercise test on a treadmill were determined for a group of female soccer athletes (n = 15) before and following an 8‐week endurance training protocol. The predicted (pVO2max) and observed (aVO2max) values were compared at baseline and within 1‐week post‐training. Change values (i.e., the difference between pre to post) for each variable were also determined and compared. There was a significant difference between aVO2max before (43.2 ± 2.8 ml. kg. min‐1) and following (46.2 ± 2.1 ml. kg. min‐1) the 8‐week training program (p < 0.05). However, pVO2max did not significantly change following training (pre = 43.4 ± 4.6 ml. kg. min‐1, post = 42.9 ± 4.1 ml. kg. min‐1, p = 0.53). Furthermore, the correlation between the change in aVO2max and the change in pVO2max was trivial and non‐significant (r = 0.30, p = 0.28). The HRindex Method does not appear to be suitable for predicting changes in VO2max following 8‐weeks of endurance training in female collegiate soccer players