lst stands for low stress training, and it's pretty much bondage for plants... it's pretty much like it sounds.. you tie the plants down to keep them shorter, and also to redistribute the auxins much in the way topping or fimming does..
which takes me to fim.. fim is actually an acronym, which stands for fuck i missed... it started off when someone was trying to top their plants, but, you guessed it, missed the complete top, and instead they only cut about 3/4's of the main growing tip off instead of the entire thing, like one would do when they top..
give me a second, and i'll get a pix for both topping and fimming to show the difference..