Energy Sources at Peak All-out Exercise in Adolescents and Young Adults

Purpose: To examine the aerobic energy portion utilized during the Wingate Anaerobic Test. Methods: Power output was compared with direct values obtained from measured oxygen uptake (VO2), in 14 (14.4 ± 1.0 yrs) healthy adolescents and 14 young adults (26.0 ± 1.0 yrs). Results: All subjects completed the exercise challenges without ECG abnormality. At rest, significant (P<0.05) differences were noted between the groups in heart rate, and diastolic blood pressure. At peak exercise, significant (P<0.05) differences were noted between adolescents and young subjects for oxygen uptake (21.5 ± 0.3 vs. 18.3 ± 0.3 mLO2 × kg-1 × min-1 respectively), power output for 30 s (0.63 ± 0.3 vs. 0.78 ± 0.3 LO2 × min-1/2 respectively), aerobic energy portion utilized (40.7 ± 4.7 vs. 17.7 ± 3.2 % respectively) and lactic acid (8.5 ± 0.7 and 12.6 ± 1.1 mmol × L-1 respectively). In addition, differences were seen in heart rate, systolic blood pressure, diastolic blood pressure, and mean arterial blood pressure. Conclusions: The results reflect a significant noticeably lower anaerobic power output during adolescence, which suggests that glycolytic activity is age-dependent. This may be related to different muscle substrate, enzyme activity and differences in phosphorus compounds between fast and slow fiber types. As a result, adolescents relied more on oxidative metabolism compared to young adults.