Application of a standardised treadmill exercise test for clinical evaluation of fitness in 10 thoroughbred racehorses.

Clinical exercise stress testing is an important diagnostic tool for evaluating exercise intolerance and degree of fitness in human athletes. The purpose of this paper was to describe the methodology necessary to perform a clinical exercise test and report the results of performance evaluations on 10 Thoroughbred racehorses using this test. The test utilised an open flow gas analysis system for ease of use with untrained horses and a fast time response lactate analyser for rapid data analysis. Exercise test measurements used to evaluate fitness included peak oxygen consumption (mean VO2peak = 161.9 +/- 12.9 ml/kg/min), peak heart rate (mean HRpeak = 232 +/- 10 b/m), peak venous blood lactate concentration (mean LAC peak = 15.2 +/- 5.8 mmol/l), peak packed cell volume (mean PCV peak = 0.64 +/- 0.3 l/l) and the maximum number of steps completed (mean STEPmax = 8.7 +/- 0.5 steps). The relationship between these exercise test measurements with velocity and time post exercise was also evaluated. Change in serum creatine kinase levels resulting from exercise test were minimal (mean delta SCK = 72 +/- 53 u/l).