The reasons

for the gap are manifold, not least because it
takes the opponent out of his striking range. What it also
does is take the opponent from a state of reaction to a state
of response -from 'fight' response to 'flight' response. Let
me explain: if you shove the opponent, but not out of range,
he may automatically react to the shove with a countershove,
or an attack, of his own. He'll do this without even
thinking because it is an automatic reaction. Whilst in fight
or flight mode we are in what is known as 'mid-brain', and in
midbrain we are hardly discernible from animals. Our prime
objective in mid-brain is survival, and if that means running
away that is what our instinct will get us to do. In effect, by
staying within strike range you are forcing the opponent into
a 'fight' response, and he will react like a cornered animal.