The purpose of this study was to compare the ventilatory breakpoints during exercise between young boys and adult men. Twenty-four active volunteers, 12 boys (10.8 ± 0.3 years of age) and 12 men (24.6 ± 1.1 years of age) with similar aerobic power (53.6 ± 4.2 to 55.7 ± 3.5 mlkg−1min−1), participated in the study. Each participant completed a standardized Physical Activity Questionnaire and anthropometric variables were measured. The exercise testing consisted of two graded tests to exhaustion on a treadmill. Heart rates were recorded every minute and gas exchange parameters were obtained every 30 s throughout the tests. Each ventilatory breakpoint was determined using a three-part model. Although the relative VO2peak values were not significantly different between the boys and the young adults, the boys reported significantly (p < .05) higher total activity than the adults. The boys had a significantly higher (p > .05) first ventilatory breakpoint expressed as a percentage of VO2peak than the adults (64.9% vs. 57.7%). Only 50% of the boys demonstrated a discernable VB2, and the VB2 of this group was not significantly different from that of the adults.
The authors are with the Department of Physical Education and Kinesiology, Brock University, St. Catharines, Ontario.