Table 1

Normative reference values recommended for use by European Cystic Fibrosis Society Exercise Working Group (ECFS EWG)

Reference	Modality	Equation
Jones et al26	Cycle ergometry	VO_2max (L/min) = −0.62 sex (0 male, 1 female) + 0.046 height (cm) – 0.021 age (years) – 4.31
Orenstein21	Cycle ergometry	Female: VO_2peak (L/min) = 3.08806 height (m) – 2.877 Male: VO_2peak (L/min) = 4.4955 height (m) – 4.64
Werkman et al40	Cycle ergometry	VO_2peak = 216.3–138.7×sex (0 male, 1 female) + 11.5 × W_peak
ACSM41	Treadmill	VO₂ (mL/kg/min) = 3.5 + 0.1 × speed (m×min^–1) + 1.8 × speed×fractional grade VO₂ (mL/kg/min) = 3.5 + 0.2 (speed)+0.9 (speed; fractional grade)
Bruce et al42	Treadmill	VO_2max (mL/kg/min) = 6.70–2.82 sex (1 male, 2 female) + 0.056 (duration in seconds)
Foster et al43	Treadmill	VO_2peak (mL/kg/min) = 14.8–1.379×time (min)+0.451 × time (min)² – 0.012×time (min)³
Pollock et al44	Treadmill	VO_2peak(mL/kg/min) = 0.073 × time (seconds) – 3.9

Data obtained from ECFS EWG Statement on Exercise Testing.5 Further reference data are recommended by ECFS EWG for treadmills, but these are in the form of percentiles and not an equation to derive a ‘per cent of predicted’ value.45–48
ACSM, American College of Sports Medicine; VO_2max, maximal oxygen uptake; W_peak, peak work rate.