VO2MAX CRITERIA WHEN TESTING GIRLS:

Criteria used to determine whether a child or adolescent has given maximal effort during a VO2max test typically include precise lower limits for peak heart rate (HRpeak) and respiratory exchange ratio (RERpeak), and to a lesser extent, a VO2 plateau with increasing exercise intensity. Specific criteria may vary among laboratories, and have been developed primarily with data collected from adults. Most studies performed on youth have included small samples of boys. PURPOSE Our main purpose was to determine whether different HRpeak and RERpeak cut points affect girls' VO2max values determined from incremental treadmill tests. A secondary purpose was to determine if VO2max differs between girls who achieved a VO2 plateau and those who did not. METHODS Our sample included 453 healthy girls (M•SD age = 13.3 ± 1.65 yr, ht = 1.57 ± 0.08 m, wt = 53.4 ± 13.3 kg) who participated in studies we conducted over the past 10 years. Each participant completed a treadmill test to volitional exhaustion, with respiratory gases and HR monitored continuously. HRpeak cut point groups were 0 = 180–189 b±min−1 (n = 80), 1 = 190–194 b•min−1 (n = 83), 2 = 195–199 b•min−1 (n = 84), 3 = 200–204 b•min−1 (n = 111), 4 = ±205 b•min−1 (n = 95). RERpeak cut point groups were 0 = 0.90–0.99 (n = 29), 1 = 1.00–1.04 (n = 63), 2 = 1.05–1.09 (n = 86), 3 = 1.10–1.14 (n = 98), 4 = 1.15–1.19 (n = 79), and 5 = •1.20 (n = 98). RESULTS MANOVA revealed VO2max (ml•kg−1•min−1) differed significantly among HRpeak groups, 0 = 34 ± 7a, 1 = 35 ± 8a, 2 = 38 ± 7b, 3 = 40 ± 8b, 4 = 42 ± 7bc (letters indicate significant differences among groups; P < 0.001) but not RERpeak, 0 = 37 ± 7, 1 = 37 ± 9, 2 = 38 ± 8, 3 = 38 ± 8, 4 = 38 ± 8, 5 = 38 ± 7. There was no interaction between the two criteria. In studies where evidence of a VO2 plateau was examined, there was no difference between VO2max values of girls who reached a plateau (34 ± 7 ml•kg−1•min−1; n = 54) and those who did not (34 ± 7 ml•kg−1•min−1; n = 83). CONCLUSION On average, girls' VO2max values were not affected by choice of RERpeak criteria or requiring evidence of VO2 plateau. However, lower HRpeak cut points were associated with lower VO2max values. It is not known if this was a result of less effort by these study participants, or a cardiovascular limit to their aerobic energy production.