One of the most used approaches in the context of human performance have recently been wearable trunk accelerometers. However, what still remains unknown is if measurements derived from these trunk accelerometers can be used to detect the effect of fatigue as well as predict sports performance in the context of running. The purpose of this project was to investigate if running performance could be predicted with accelerometer data and what were the effects of fatigue (for non-injured, injured and all subjects) on accelerometry-based measurements. One hundred and eighty runners aged 17-23 years completed the Cooper test. Using windows corresponding to 20 running steps from all acceleration directions (Vertical, VT, Mediolateral, ML and Anteroposterior, AP) for the first and last part of the Cooper test, the following accelerometry based-measurements of stability were extracted: the tri-axial ratio of acceleration root mean square (acceleration RMS ratio) normalized with the resultant vector RMS of all acceleration directions and applied to all acceleration directions separately, step and stride regularity (SReg and strReg respectively obtained with the autocorrelation procedure), and sample entropy (SE). No evidence could be found for establishing a correlation between accelerometry-based measurements of stability and running performance. However, running-induced fatigue resulted in a decrease of the ratio of acceleration RMS and SReg in the VT direction but in an increase for the Ratio RMS in the ML direction, StrReg ML and AP and SE VT. In addition to that, injured subjects had a less complex running gait in the ML direction and an interaction effect was found between subjects sustaining an injury and running-induced fatigue for the strReg AP. We can conclude that an accelerometer positioned in the trunk can be used to detect deviations in the CoM due to induced running-fatigue in outdoor running environments, that musculoskeletal pathology can decrease movement complexity and that the increase in regularity between steps in the horizontal plane with running fatigue is related to injury.