If a person is running in a circle, what force imparts centripetal acceleration to him?

When a person runs in a circle, the force of centripetal acceleration, he communicates to himself. While running, a person constantly changes the direction or vector of his movement. Having run half a circle, a person changes his vector of movement to the opposite. That is, as if he stopped and ran in the opposite direction. And while running, he constantly changes his motion vector, and to compensate for this, an additional centrifugal force arises, which the person himself overcomes. This is just one of the manifestations of the force of inertia.