The purpose of this study was to assess the reliability of 24 kinetic and kinematic variables from three synchronized systems used to represent normal running gait. Five male runners (mean 23.4 years, mass 80.2 kg) ran down a runway at a constant velocity (3.5-4.0 m/s). This was repeated until 10 acceptable trials had been performed which was then repeated 7 days later. The mean of the 10 trials was used for kinetic analysis and the mean of 5 trials for the kinematics. All of the kinematic variables achieved a reliability greater than 0.93. The 6 variables that were able to demonstrate a high reliability (>0.94) from a single trial came from all systems. This suggests that variables and systems used to collect and analyse gait should be assessed for their reliability using the population to be studied before actual data collection.