Goal posts at the ends of football fields are padded as a safety measure for players who might run into them. how does thick padding around the goal post reduce injuries to players?

The answer given by E2020 is

"The padding around the goal post increases the time of the collision between the player and the post, which decreases the force exerted to bring the player to a stop"

Explanation :

Goal posts at the ends of football fields are padded as a safety measure for players who might run into them.

This is due to thick padding around the goal post reduce injuries to players. In a physics point of view, this would decrease the force.

According to Newton's second law, F = m a

or

The thick padding increases the time of interaction of the player and the post. As a result, the force will decrease.

Hence, the chances of injury can be reduced.