Table 2 Z-score equations of CPET parameters
CPET parameters | Sex | Z-score equations | N | R2 | 5th percentile | Median | 95th percentile |
|---|---|---|---|---|---|---|---|
HRmax (bpm) | All gender | \({\text{Z - score}} = \frac{{\left( {{\text{HR}}_{{{\text{max}}}} \left( {{\text{bpm}}} \right) - 188.1} \right)}}{8.9}\) | 909 | – | − 1.70 | − 0.01 | 1.67 |
RERmax | Girls | \({\text{Z - score}} = \frac{{{\text{RER}} - 0.985 - 0.015 \times {\text{age}}_{{\left( {{\text{years}}} \right)}} }}{0.098}\) | 431 | 0.14 | − 1.46 | 0.01 | 1.73 |
|  | Boys | \({\text{Z - score}} = \frac{{\ln_{{{\text{RER}}}} + 2.01 - 0.475 \times \ln_{{{\text{height}}\left( {{\text{cm}}} \right)}} + 0.064 \times \ln_{{{\text{weight}}\left( {{\text{kg}}} \right)}} }}{0.0769}\) | 477 | 0.16 | − 1.79 | 0.08 | 1.44 |
Workloadmax (Watts) | Girls | \({\text{Z - score}} = \frac{{\ln_{{{\text{load}}}} + 5.951 - 1.947 \times \ln_{{{\text{height}}\left( {{\text{cm}}} \right)}} - 0.39 \times \ln_{{{\text{age}}\left( {{\text{years}}} \right)}} }}{0.1932}\) | 390 | 0.60 | − 1.61 | − 0.02 | 1.58 |
|  | Boys | \({\text{Z - score}} = \frac{{\ln_{{{\text{load}}}} + 7.662 - 2.309 \times \ln_{{{\text{height}}\left( {{\text{cm}}} \right)}} - 0.408 \times \ln_{{{\text{age}}\left( {{\text{years}}} \right)}} }}{0.1713}\) | 419 | 0.76 | − 1.82 | 0.09 | 1.66 |
O2 pulsemax (mL) | Girls | \({\text{Z - score}} = \frac{{\ln_{{02{\text{pulse}}}} + 6.266 - 1.049 \times \ln_{{{\text{weight}}\left( {{\text{kg}}} \right)}} + 0.091 \times \ln_{{{\text{weight}}\left( {{\text{kg}}} \right)}} \times \ln_{{{\text{weight}}\left( {{\text{kg}}} \right)}} - 1.147 \times \ln_{{{\text{height}}\left( {{\text{cm}}} \right)}} }}{0.1484}\) | 432 | 0.69 | − 1.66 | − 0.04 | 1.82 |
|  | Boys | \({\text{Z - score}} = \frac{{\ln_{{02{\text{pulse}}}} + 8.04 - 0.15 \times \ln_{{{\text{weight}}\left( {{\text{kg}}} \right)}} - 1.946 \times \ln_{{{\text{height}}\left( {{\text{cm}}} \right)}} }}{0.1458}\) | 477 | 0.77 | − 1.64 | − 0.01 | 1.60 |
VAT (mL/min) | Girls | \({\text{Z - score}} = \frac{{\ln_{{{\text{VAT}}\left( {\text{mL/min}} \right)}} - 1.603 - 0.7875 \times \ln_{{{\text{height}}\left( {{\text{cm}}} \right)}} - 0.3824 \times \ln_{{{\text{weight}}\left( {{\text{kg}}} \right)}} }}{0.1872}\) | 432 | 0.54 | − 1.55 | − 0.02 | 1.73 |
|  | Boys | \({\text{Z - score}} = \frac{{\ln_{{{\text{VAT}}\left( {\text{mL/min}} \right)}} + 1.5616 - 1.5681 \times \ln_{{{\text{height}}\left( {{\text{cm}}} \right)}} - 0.228 \times \ln_{{{\text{weight}}\left( {{\text{kg}}} \right)}} }}{0.1714}\) | 477 | 0.68 | − 1.83 | − 0.08 | 1.65 |
VE/VCO2 slope | Girls | \({\text{Z - score}} = \frac{{\ln_{{\frac{{{\text{VE}}}}{{{\text{VCO}}_{2} }}{\text{slope}}}} - 3.80 + 0.158 \times \ln_{{{\text{age}}\left( {{\text{years}}} \right)}} }}{0.1411}\) | 423 | 0.06 | − 1.61 | 0.03 | 1.74 |
|  | Boys | \({\text{Z - score}} = \frac{{\ln_{{\frac{{{\text{VE}}}}{{{\text{VCO}}_{2} }}{\text{slope}}}} - 4.016 + 0.255 \times \ln_{{{\text{age}}\left( {{\text{years}}} \right)}} }}{0.123}\) | 469 | 0.19 | − 1.67 | − 0.03 | 1.62 |
OUES | Girls | \({\text{Z - score}} = \frac{{\ln_{{{\text{OUES}}}} - 0.4262 - 1.1554 \times \ln_{{{\text{height}}\left( {{\text{cm}}} \right)}} - 0.3173 \times \ln_{{{\text{weight}}\left( {{\text{kg}}} \right)}} }}{0.1906}\) | 301 | 0.57 | − 1.67 | − 0.03 | 1.61 |
|  | Boys | \({\text{Z - score}} = \frac{{\ln_{{{\text{OUES}}}} + 3.1486 - 2.0259 \times \ln_{{{\text{height}}\left( {{\text{cm}}} \right)}} - 0.1520 \times \ln_{{{\text{weight}}\left( {{\text{kg}}} \right)}} }}{0.1848}\) | 355 | 0.67 | − 1.71 | − 0.02 | 1.62 |
VTmax (L) | Girls | \({\text{Z - score}} = \frac{{\ln_{{{\text{VTmax}}\left( {\text{L}} \right)}} + 12.1409 - 2.3285 \times \ln_{{{\text{height}}\left( {{\text{cm}}} \right)}} - 0.17293 \times \ln_{{{\text{weight}}\left( {{\text{kg}}} \right)}} }}{0.17085}\) | 432 | 0.72 | − 1.51 | − 0.04 | 1.64 |
|  | Boys | \({\text{Z - score}} = \frac{{\ln_{{{\text{VTmax}}\left( {\text{L}} \right)}} + 13.4373 - 2.6582 \times \ln_{{{\text{height}}\left( {{\text{cm}}} \right)}} - 0.0998 \times \ln_{{{\text{weight}}\left( {{\text{Kg}}} \right)}} }}{0.1727}\) | 477 | 0.78 | − 1.68 | 0.00 | 1.61 |
RRmax (1/min) | Girls | \({\text{Z - score}} = \frac{{{\text{RR}}\left( {1/\min } \right) - 73.62 + 0.161 \times {\text{height}}\left( {{\text{cm}}} \right)}}{9.56}\) | 428 | 0.05 | − 1.54 | − 0.05 | 1.58 |
|  | Boys | \({\text{Z - score}} = \frac{{\ln_{{RR\left( {1/\min } \right)}} - 4.42 + 0.133 \times \ln_{{{\text{weight}}\left( {{\text{kg}}} \right)}} }}{0.194}\) | 467 | 0.07 | − 1.72 | 0.04 | 1.47 |
BR (%) | Girls | \({\text{Z - score}} = \frac{{{\text{BR}}\left( \% \right) - 28.70}}{15.48}\) | 432 | – | − 1.85 | 0.07 | 1.56 |
|  | Boys | \({\text{Z - score}} = \frac{{{\text{BR}}\left( \% \right) - 24.31}}{13.71}\) | 476 | – | − 1.77 | 0.05 | 1.51 |
VEqCO2max | All gender | \({\text{Z - score}} = \frac{{\ln_{{{\text{VeqCO}}_{2} }} - 3.421}}{0.1195}\) | 909 | – | − 1.66 | 0 | 1.66 |
VEqO2max | Girls | \({\text{Z - score}} = \frac{{\ln_{{{\text{VeqO}}_{2} }} - 3.575}}{0.1602}\) | 432 | – | − 1.56 | 0.01 | 1.60 |
|  | Boys | \({\text{Z - score}} = \frac{{\ln_{{{\text{VeqO}}_{2} }} - 3.544}}{0.1488}\) | 477 | – | − 1.62 | − 0.06 | 1.80 |