Distance over Time in a Maximal Sprint: Understanding Athletes' Action Boundaries in Sprinting

The present study examined the kinematics of maximal effort sprint running, mapping the relations among a person's maximal running speed, maximum running acceleration and the distance coverable in a certain amount of time by this person. Thirty-three participants were recruited to perform a simple sprint task. Both forward and backward running were considered. Participants' position, velocity and acceleration data were obtained using a Local Positioning Measurement system. Participants' speed-acceleration profiles turned out to be markedly non-linear. To account for these non-linear patterns, we propose a new macroscopic model on the kinematics of sprint running. Second, we examined whether target distance was of influence on the evolution of participants' running speeds over time. Overall, no such effect on running velocity was present, except for a 'finish-line effect'. Finally, we studied how variation in individuals' maximum running velocities and accelerations related to differences in their action boundaries. The findings are discussed in the context of affordance-based control in running to catch fly balls.