Friction is the resistance that one surface or object encounters when moving over another. With every step you take, you push backward, and your shoe tries to slide past the ground. If there were no friction, you'd slip and slide all the time as if you were wearing socks on linoleum. Since there is plenty of friction, however, you don't slip, and can push against the ground to move yourself forward.
Middle and long distance runners in track often don't wear shoes with spikes. This is because they aren't pushing hard enough that there is a risk of slipping - their events are about endurance, not speed and power. Sprinters, on the other hand, are producing much greater forces at the interface between their feet and the track. Their spikes grip onto the track, allowing them to push against the sides of the hole the spike makes - no friction needed.
A runner also experiences friction between the air and their body/clothes. Air resistance increases greatly with speed - again, the sprinters will often wear different equipment. They'll wear tighter clothes made of special materials to reduce drag.
Middle and long distance runners in track often don't wear shoes with spikes. This is because they aren't pushing hard enough that there is a risk of slipping - their events are about endurance, not speed and power. Sprinters, on the other hand, are producing much greater forces at the interface between their feet and the track. Their spikes grip onto the track, allowing them to push against the sides of the hole the spike makes - no friction needed.
A runner also experiences friction between the air and their body/clothes. Air resistance increases greatly with speed - again, the sprinters will often wear different equipment. They'll wear tighter clothes made of special materials to reduce drag.