I specifically didn't deal with mawai because it can always be different relative to the techinque and intent.
However, kicks always work in an arc from the point of origin to the target. Punches can work in an arc or in a straight line similar to a piston.
Of course there are different styles of kicking, etc. Off-line/entering into the origin of the kick is the answer, in my experience.
Shinto Muso Ryu Jo techinques (at higher level in the system) often include stepping on the attacker's foot. I often do it in our Jiyushinkai style of randori, too, although you must be very careful as it is easy to hurt someone in practice.
[Edited by Chuck Clark on August 6, 2000 at 01:02pm]