Answer: Ground reaction force (GRF)
Explanation:
Ground reaction force (GRF) is the force that is exerted by the ground surface towards the body or on the person that has the contact with it.This force acts opposite to the force of action to support the body.
According to the situation described in question, when any sportsperson or athlete is running on the ground, ground reaction force tends to act on the athlete/runner from the ground.
It is created as the runner is running and ground supports the athlete to move forward by giving opposite reaction in regard with the action of pushing the ground down by athlete.
