This study examined the applicability of criteria for maximal oxygen consumption (V̇O₂max) in adolescents. Active females (n=38) and males (n=196) who were students at a sports-technical junior high school performed a treadmill Bruce protocol to volitional fatigue. The criteria for V̇O₂max were R ≥1.0, HR ≥95% of predicted maximal for age, and an increase in V̇O₂ ≤2.1 ml·kg⁻¹·min⁻¹ with an increase in workload. The first criterion was met by 97% of the females and 93% of the males, while 81% of the females and 75% of the males met the second criterion. Only 8% of the females and 13% of the males met the third criterion. Those who achieved a plateau showed higher HR at peak exercise compared to those who did not (204 ±7.0 vs. 200.6 ±7.2, P≤0.05). Our data indicate that a high proportion of adolescents exhibit subjective and objective indicators of maximal performance without showing a plateau in V̇O₂. Age-specific criteria for V̇O₂max should be developed.