I suspect that phonetic and local variation of the pronunciation of Japanese words comes to play:
"san-chim" may very well be "zanshim" (positive follow-through of a strike and alertness against a potential counter-attack.) Hence the forward running...
Kendo-Guide.Com: I have to look at the kanji (Japanese character) for san-chim. I still have no idea what it is. I am not sure it is Japanese without knowing its kanji.