Objective: Eight phases of the normal gait cycle (GC) were described X years ago.The percent of time (PT) spent in each phase of the GC helped define abnormal gait.We sought to characterize the PT of the GC as velocity changed to establish norms for pathological gait characteristics with modern higher resolution technology in order to be clinically beneficial.Method: Ninety five healthy subjects (51 males and 44 females) were enrolled in the study.Subjects walked comfortably on a 10-meter walkway at self-selected normal, fast, and slow velocity.Walking was recorded with a high speed camera (250 frames per second) and the eight phases of GC were determined by examination of individual frames for each subject at their various walking velocities.Other spatial-temporal parameters were calculated using motion analysis software.Results: The correlation coefficients for the mean percentages of GC were all greater than 0.99 for the three gait velocities.The mean percentage of initial contact (IC) for normal velocity gait was 1.81% (range 1.08 ~ 2.59 %), loading response (LR) was 12.89% (range 8.33~15.73%) and midstance (MSt.) was 31.56% (range 19.05~40.47%).Correlation coefficients (CC) between velocity and mean PT of gait phases-0.06 for IC,-0.83 for LR,-0.75 for MSt,-0.02 for terminal stance,-0.84 for pre-swing,-0.36 for initial swing, and-0.22 for midswing.Discussion: While the mean PT of GC are highly correlated with normal walking velocity, actual PT of each phase varied amongst these individuals with the largest coefficient variation of 24.31%.The PT is also affected by the gait velocity.From slow to rapid velocity the PT of MSt diminished from 35.30% to 25.30%.High resolution recording revealed moments of GC differentiation ambiguity.Conclusion: The PT of a GC varies from among individuals and was affected by walking velocity.High resolution recording revealed that these data may benefit GC characterization of normal and pathological gait in clinical practice.