I always wear boots when I train so that my foot becomes an extension of my...well, I guess, My HAND.
I kick mine with the toe of my boot under their head (further back from the chin/curbchain area.) They always pay attention to that. You don't have to kick hard as if you are punting a football. I also say, "head up" at the same time so as to teach them an "English" command. My horses are usually surprised by this but not frightened. ALL I want is to not have to yank or bend over, where I am in a compromised physical position. Yanking away to eat more is a pet peeve of mine, especially with 3 easy keepers who have been wasting expensive hay lately. =/
My horses and dogs understand a LOT of English. When I walk the cat walk above their shelter's manger, I say the name of my horse and say, "watch your head" when I fill it. They move their heads away so that they aren't covered with hay.
Btw, I have heard that some multilingual people praise their horses in French and audibly discipline them in German. Just an FYI.