Peak Responses to Graded Exercise Protocols in Young Children

ABSTRACT Introduction This study compared physiological and subjective measures resulting from maximal graded exercise testing (GXTmax) when the traditional Bruce protocol and a protocol designed specifically for pediatric populations (Pediatric Exercise Physiology (PEP) Lab protocol) were employed in children of varying adiposities. Methods Participants included 48 children (24 males, 24 females; ages 7–11 yr). GXTmax variables of interest included peak oxygen consumption (V·O 2peak ), peak heart rate (HRpeak), peak systolic blood pressure (SBPpeak), peak respiratory exchange ratio (RERpeak), and protocol duration. Participants were also asked to subjectively determine which GXTmax they perceived as more difficult. Results Comparing the whole group, there were no significant differences in V·O 2peak or HRpeak between protocols; however, the PEP Lab GXTmax produced significantly greater SBPpeak and significantly lower RERpeak. All physiological variables were moderately or strongly associated between the two protocols (explained variance ranged from 23.9% to 68.5%). In addition, 87.5% of participants subjectively rated the PEP Lab protocol as easiest to complete. Conclusions Although similar V·O 2peak and HRpeak measures were achieved, a lower perceived level of difficulty was observed for the PEP Lab protocol. We speculate that the PEP Lab protocol resulted in higher SBPpeak and lower RERpeak due to the lower initial intensity and smaller stage intensity increments, which may have permitted more gradual cardiorespiratory and metabolic adjustments.