Hierarchy of changes induced by fatigue in sprinting

Five female sprinters ran 400m. on successive occasions during which they were filmed at 100m. (initial) and 380m. (final). Times and ranges of motion for specific segments of the running cycle were obtained and their changes from initial to final stages of the runs were analyzed. A hierarchical approach was taken in which a gross change was broken down into its separate parts for subjects individually and the group as a whole. The decrease in velocity with fatigue resulted from different combinations of changes in step length and cycle time. Different hierarchical patterns of temporal and kinematic variables were observed among subjects with the result that the hierarchical pattern for the group frequently obscured significant individual changes. It is suggested that the hierarchical approach be taken for the establishment of both present status and effects of training on the individual athlete.