The first Newton law of motion is an object at rest will remain at rest unless acted on by an unbalanced force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
A runner at rest will remain at rest until he/she force in acts upon it. when the runner's foot pushes on the ground, the earth will push back, sending the runner forward.
The second Newton's law of motion is the acceleration of an object is determined by the size of it's net.
The force you exert while running will cause you to move forward. Your movement forward directly relates to the applied force and the net force which is proportionally related to your mass.
The third Newton's law of motion is when one object exerts a force on a second object, the second object also exerts an equal force on the first object in the opposite direction.
When your foot comes in contact with the ground it pushes back with an equal and opposite force propelling you forward.
In this video it describes to you more about running and the movement, the force or the motion you will see in races or even when you run. Also how much forces you have to put so you can move forward faster.