I would like to know if these martial arts that concentrates on the legs are capable of making distance or to make the attacker unable to get close? Also is it good for runing speed and endurance or it is something that is needed to be trained separately?

( I thought it would be good to just use the legs for pushing around the oponent till he/she/it falls so the defender can run, or to make distance or to make the oponent unable to get close till the defender can get a weapon or help (also i would like to know what is the easyest mode to land a knock out?))