Differences between treadmill and cycle ergometer cardiopulmonary exercise testing results in amateur triathletes and their association with body composition and body mass index

Cardiopulmonary exercise testing (CPET) is the method of choice to assess aerobic fitness. Previous research was ambiguous as to whether treadmill (Tr) and cycle ergometry (CE) results are transferrable or different between testing modalities in triathletes. The aim of this paper was to investigate the differences in HR and VO 2 at maximum exertion and at anaerobic threshold (AT) and respiratory compensation point (RCP) and evaluate their association with body fat (BF), fat free mass (FFM), and body mass index (BMI). 143 adult (n = 18 female), amateur, Caucasian triathletes had both Tr, and CE CPET performed. The male group was divided into  40years (n = 45). Body composition was measured with bioelectrical impedance before tests. Differences were evaluated using paired T-tests and associations were evaluated in males using multiple linear regression (MLR). Significant differences were found in VO 2 and HR at maximum exertion, at AT and at RCP between CE and Tr testing, in both males and females. VO 2AT was 38.8(± 4.6) ml/kg/min in Tr vs 32.8(± 5.4) in CE in males and 36.0(± 3.6) vs 32.1(± 3.8) in females (p < 0.001). HR AT was 149 (± 10) bpm in Tr vs 136 (± 11) in CE in males and 156 (± 7) vs 146 (± 11) in females (p < 0.001). VO 2 max was 52 (± 6) ml/kg/min vs 49 (± 7) in CE in males and 45.3 (± 4.9) in Tr vs 43.9 (± 5.2) in females (p < 0.001). HRmax was 183 (± 10) bpm in Tr vs 177 (± 10) in CE in males and 183 (± 9) vs 179 (± 10) in females (p  40. Both tests should be used independently to achieve optimal fitness assessment and further training planning.