Objective: 

We have comparatively investigated the relationships between anaerobic threshold (AT), respiratory compensation point (RCP) and critical power (CP) to determine an optimum exercise training protocol for clinical and sports science.

Methods: 

A total of 25 male subjects (22.8+/-3.6 yr, 76+/-8.8 kg) performed an incremental exercise test and 7 different constant load exercise tests using an electromagnetically-braked cycle ergometer. AT and RCP were estimated from ventilation and respiratory gas exchange parameters. The data were evaluated breath-by-breath. The constant load exercise protocols were designed using AT and the mean duration of performed exercise tests were recorded. CP was estimated with linear (power-(1/time)) mathematical model using the data obtained from these tests. The Linear Regression Analysis and the paired t-test were used to compare values between the dependent groups. This study was approved by the local ethics committee, and informed (signed) consent was obtained from all subjects.

Results: 

The work rate was found to be 117+/-22 W at AT and 13^2+/-27 W at

RCP. CP values were found to be 141+/-31 W in 3 test model analysis and 133+/-27 W in 4 test model analysis.There was a significant correlation between the values estimated from linear regression analysis power-(1/time) models (4 test model) and CP estimated using RCP (R=0.986 p<0.0001).

Conclusions: 

The present findings have shown for the first time that CP reflects the RCP and CP can be estimated easily using pulmonary gas exchange variables. The number of tests used for mathematical modelling to estimate CP and the relation between the work rate used in the constant load exercise test and work rate at RCP are important factors affecting CP estimation.