The researcher supposes that pull-resisted runs develop acceleration phase, in which the runner's rate of velocity gradually increased for the longest possible distance, in other words, picking up acceleration to dilly maximum velocity. Runners pull additional weights (mass), which enable them to store more energy to improve muscle actions, which in turn improve support time and its relation to frequency and stride length in un-resisted run, without negatively influence the running technique.  Therefore, the researcher, in this study, identifies the biomechanics of stride length with pull-resisted runs of acceleration phase, and its impact on the technique and velocity.