Peak oxygen consumption of highly trained cyclists: is there a difference between lab and field testing?

Maximum oxygen consumption (V̇O2max) is considered the gold standard measure and key performance predictor for endurance sports. As “the highest rate at which oxygen can be taken up and utilised by the body during severe exercise” (Bassett and Howley, 2000, Medicine and Science in Sports and Exercise, 32, 70-84), V̇O2max is usually measured through ergometer-based laboratory tests typically lasting 8-12 minutes. However, traditional V̇O2max testing lacks the ability to regulate intensity due to fixed resistance and a lack of conscious decision making (Noakes, 2008, British Journal of Sports Medicine, 42, 551-555). Our study aimed to determine if a field-based test involving a cycling hill climb would prove a superior method of assessing V̇O2peak compared to a traditional laboratory-based test. V̇O2peak rather than V̇O2max was used due to issues regarding secondary criteria being excessively stringent or lenient to determine true V̇O2max attainment (Poole, Wilkerson & Jones, 2008, European Journal of Applied Physiology, 102, 403-410) and also to allow participants’ results to be directly compared between their lab and field tests. V̇O2peak was determined as the highest individual breath in a tightly clustered series. Twelve highly trained cyclists with over 2 years racing experience (Mean ± SD, Age 28.4 ±12yrs, height 182.8 ±7cm, mass 77 ± 10.9kg) performed a 20w/minute ramp test on a cycle ergometer and a hill climb (3.2km/ 5.4% average gradient) on their own racing bike wearing a portable gas analyser in highly similar environmental conditions in the first field based V̇O2peak test involving cyclists. Statistical analysis using a paired t-test revealed no significant difference in absolute V̇O2peak: lab 5.49 ± 0.8 L·min-1 vs. field 5.59 ± 0.7 L·min-1 , p = .189, relative V̇O2peak: lab 71.9 ± 10.0 ml·kg-1·min-1 vs. field 74.0 ± 9.9ml·kg-1·min-1, p = .060, or HRpeak: lab 187 ± 11 b·min-1 vs. field 187 ± 10 b·min-1, p = .952. However end lactate was significantly higher in the field: 9.24 ± 1.6 mmol·L-1 vs. field 11.99 ± 2.3 mmol·L-1, p = .039, 5-minute-post lactate: lab 7.56 ± 1.4 mmol·L-1 vs. field 11.87 ± 2.0 mmol·L-1 p < 0.001 and RERpeak: lab 1.07 ± 0.0 vs. field 1.16 ± 0.1, p = .019. Interestingly, there was no significant difference in absolute or relative V̇O2peak between lab and field tests. Therefore, field V̇O2peak testing may be considered a viable alternative to lab-based testing if a road of sufficient length and gradient is available.