‘Simchat Torah’ is an exuberant dance performed while holding the Torah wrapped in its mantle.  The Torah wants to dance but as it has no feet; a Jew must become ‘the feet of the Torah’. 

Think of it this way:

“The foot is utterly nullified to the will of the brain, as we can see from the fact that a person’s thought-impulse to move his foot is instantly obeyed. A foot that does not heed the command of the brain is not healthy.

Similarly the dancing of Simchat Torah expresses complete acceptance of the Heavenly yoke and submission… the Torah’s commands are fulfilled without hesitation or deliberation.”  (Likkutei Sichot, vol. 4, p. 1169)

http://www.chabad.org/holidays/JewishNewYear/template_cdo/aid/4538/jewish/The-Feet-of-the-Torah.htm

Each week in synagogues around the world, a portion of the Torah is chanted. Over the course of a year, the entire Torah is recited.  The final reading of this cycle occurs on Simchat Torah, a Rabbinical festival celebrating both the completion of the Torah’s reading cycle and the start of the new cycle.

 http://www.hebrew4christians.com/Holidays/Fall_Holidays/Simchat_Torah/simchat_torah.html