Criteria of maximal effort and prediction equations
| Variable | Cycle test | Treadmill test | |||
| Children | Adults | Children | Adults | ||
| 1 | V′O2peak | Change of V′O2 <2 mL·min−1·kg−1 for a 5–10% increase in exercise intensity or of <2sd of the average increase in V′O2 during the preceding stages [13] | Change in V′O2 of <2.1 mL·min−1·kg−1 between consecutive stages [14] | Change of V′O2 <2 mL·min−1·kg−1 for a 5–10% increase in exercise intensity or of <2sd of the average increase in V′O2 during the preceding stages [13] | Change in V′O2 of <2.1 mL·min−1·kg−1 between consecutive stages [14] |
| 2 | V′Epeak/MVV % | ≥85 [11] | ≥85 [11] | ≥85 [11] | ≥85 [11] |
| 3 | IC | Decrease in IC >150 mL during exercise [15] | Decrease in IC >150 mL during exercise [15] | Decrease in IC >150 mL during exercise [15] | Decrease in IC >150 mL during exercise [15] |
| 4 | RER | >1.05 [16] | >1.05 [17] | >1.05 [16] | >1.05 [17] |
| 5 | HRpeak % pred or beats·min−1 | ≥195 bpm [18] | >100% pred [11] 231 men and women (aged 20–80 years) [19] Female: 209–0.86×age Male: 207–0.78×age | ≥200 bpm [18] | >100% pred [11] 3320 healthy men and women (aged 19–89 years) [17] 211–0.64×age |
| 6 | V′O2peak % pred | ≥100% predicted V′O2peak (L·min−1) [20]: Female: V′O2peak=3.08806×height (m)−2.877 Male: V′O2peak=4.4955×height (m)−4.640 | ≥100% predicted V′O2peak (L·min−1) [21]: V′O2peak=0.046×height (cm)−0.021×age−0.62×sex (0 male, 1 female)−4.31 | ≥100% predicted V′O2peak (mL·min−1·kg−1) [22]: Female: 58.90–1.15×age Male: 52.35+0.071×age V′O2peak (L·min−1): 3703 male and 1234 female children and adolescents (aged 8–16 years) [23] Male: 0.623+0.230×age (R2=0.748) Female: 0.253+0.124×age (R2=0.529) | ≥100% predicted V′O2peak (mL·min−1·kg−1) [24]: 4637 healthy men and women (aged 20–90 years) Female: 17.21+(0.582×inclination)+(3.317×velocity)−(0.116×weight)−(0.099×age) Male: 24.24+(0.599×inclination)+(3.197×velocity)−(0.122×weight)−(0.126×age) 7783 healthy men and women (aged 20–79 years) [25] V′O2 max (mL·min−1·kg−1): 79.9-(0.39×age)−13.7×sex [0 male, 1 female])−(0.127×weight [lbs]) |
| 6 | Blood lactate | Usually not informative, since there is considerable variability in post-exercise blood lactate in children (e.g. max values between 4–13 mmol·L−1 in 11–13-year old children) [26] Minimum post-exercise cut-off values to be validated [27] | Post-exercise blood lactate levels ≥8 mmol·L−1 [28, 29] | Usually not informative, since there is considerable variability in post-exercise blood lactate in children (e.g. max values between 4–13 mmol·L−1 in 11–13-year old children) [26] Minimum post-exercise cut-off values to be validated [27] | Post-exercise blood lactate levels ≥8 mmol·L−1 [28, 29] |
V′O2peak: peak oxygen uptake; V′O2: oxygen uptake; V′Epeak: peak minute ventilation; MVV: maximum voluntary ventilation; IC, inspiratory capacity; RER, respiratory exchange ratio; HRpeak, peak heart rate.