This paper presents methods for collecting and analyzing physiological and biomechanical data during recreational runs in order to classify an athlete's perceived fatigue state. Heart rate and its variability, running speed and stride frequency, GPS position and shoe heel compression were recorded continuously while runners moved freely outdoors. During their activity the sportsmen answered questions about their fatigue state in five-minute-intervals. Data from 84 one-hourruns was collected for analysis. The data was analyzed using features computed for each step of the athlete to distinguish three levels of the runner's fatigue state with an accuracy of 75.3% across multiple study participants