Change of the angular momentum in sprint running

Abstract

This paper aimed to examine error factors from the perspective of the conservation law of the angular momentum when a rigid body model is used in sprint running. Firstly, sprint runs were measured using a motion capture system and force platforms. This experimental result showed that the angular momentum vector was not conserved during the flight phase in sprint running. Also, each segment's length was not constant. This result contradicted the prerequisite of the rigid body model. On the other hand, a high stiffness pipe colliding with the force platform was captured using a motion capture system and a force platform. The pipe's angular momentum vector was accurately conserved during the flight phase. Therefore, the modeling error of the rigid body model by deformation of each segment could mainly cause the angular momentum vector not to be conserved in sprint running.