Problems involving the upper airway are a common cause of decreased athletic performance. The treadmill allows the clinician to examine the upper airway of an equine athlete while it is exercising at high speed. This type of dynamic evaluation is very useful in determining if the horse has an upper airway abnormality affecting performance. There are certain abnormalities of the upper airway that only become evident during exercise and will not be seen during a resting endoscopic evaluation. The examination is tailored to the type of work and the level of fitness for each horse, mimicking the speed and distance that the horse typically works. The endoscopic examination is recorded and evaluated in slow motion so that subtle abnormalities are identified.