Respiratory exchange ratio thresholds of ≥1.10 versus <1.10 yielded comparable VO2max in pediatric endurance athletes, with no significant difference in boys (P=0.099) or girls (P=0.124).
Does an RER cutoff of ≥1.10 compared to <1.10 result in a significant difference in measured VO2max in pediatric endurance athletes?
In pediatric endurance athletes, an RER threshold of ≥1.00 is sufficient to confirm maximal effort during CPET, as a higher threshold of ≥1.10 does not yield significantly higher VO2max values.
Absolute Event Rate: 0% vs 0%
Abstract Background Maximal cardiopulmonary exercise test (CPET) is the gold standard to assess maximal oxygen uptake (VO2max). The criteria used for maximal effort in pediatric testing vary, and those applied to endurance athletes (EA) of different training status further differ from those for untrained individuals. In pediatric CPET, respiratory exchange ratio (RER) thresholds of ≥1.00 or ≥1.10 are used interchangeably to indicate maximal effort, yet no unified criteria exist for pediatric endurance athletes (PEA). Since the diagnostic value of submaximal CPET remains limited, it is warranted to establish valid maximum effort criteria for PEA. Purpose This retrospective cross-sectional study determined whether there are differences in VO2max between the RER cutoffs in PEA. Methods From 1338 healthy recreational PEA (rPEA) referred for CPET, 1241 (92.8%) fulfilled the criteria of maximal effort, defined as (1) volitional unwillingness confirmed by a supervising physiologist with RPE≥8/10, (2) plateau in VO2max, and (3) RER≥1.00. There were 417 girls (33.6%; age=11.5±1.2 years; BMI=18.9±3.6 kg·m-2; training experience=12.8±9.9 months) and 824 boys (66.4%; age=11.7±1.1 years; BMI=18.6±3.6 kg·m-2; training experience=13.8±10.3 months). The population was divided between RER≥1.10 (group A) and RER1.10 (group B). An unpaired Student's t-test was used to compare VO2max between group A and B independently for male and female rPEA and presented with the mean difference supported by 95% confidence intervals (CI). Results Boys and girls had VO2max of 50.0±8.3 mL·kg-1·min-1 and 44.8±7.2 mL·kg-1·min-1, respectively. In boy’s rPEA, there was no significant difference in VO2max (t(822)=-1.65, P=0.099) between group A (N=397; 50.5±8.4 mL·kg-1·min-1) and group B (N=427; 49.6±8.3 mL·kg-1·min-1) with mean difference of -0.9 mL·kg-1·min-1 (95%CI, -2.0 to -0.2). In girl’s rPEA, there was also no significant difference in VO2max (t(415)=-1.54, P=0.124) between group A (N=226; 45.3±7.1 mL·kg-1·min-1) and group B (N=191; 44.2±7.2 mL·kg-1·min-1) with a mean difference of -1.1 mL·kg-1·min-1 (95%CI, -2.5 to -0.3). Conclusions Although a higher RER cutoff is associated with slightly better VO2max, VO2max is comparable between RER≥1.10 and RER1.10 in rPEA in both boys and girls. Our findings highlight a negligible practical disparity between the investigated RER cutoffs used to confirm maximal effort during CPET in rPEA, as long as the threshold ≥1.00 is maintained. Further studies on PEA of different performance calibers are warranted in the future.Central figureFor image description, please refer to the figure legend and surrounding text.
Kasiak et al. (Mon,) reported a other. Respiratory exchange ratio thresholds of ≥1.10 versus <1.10 yielded comparable VO2max in pediatric endurance athletes, with no significant difference in boys (P=0.099) or girls (P=0.124).
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