Gripping with the feet

In lieu of grounding, a common mistake is to use tension in the feet to brace yourself when executing strong strokes. Grounding with your energy, relaxing your feet and staying sensually connected with the earth will help keep you from slipping. Working on carpet or sticky mats is better than a slippery floor. When traveling it is a good idea to carry a sticky mat in case your client has hardwood floors.

-- from The Ultimate Hand Book by Maja Evans, Laughing Duck Press, 1992