The Sixth Circuit, of which Tennessee is a part, has held that reaching to the small of one’s back in a high crime area constitutes reasonable suspicion, and gives law enforcement the right to temporarily detain you.

From United States v. Pearce, 2008 U.S. App. LEXIS 14187, 2008 FED App. 0240P (6th Cir. July 3, 2008):

Officer Johnson reasonably suspected that “Johnson had a weapon and was getting ready to fire.” J.A. at 75-76. Indeed, even from a layman’s perspective, Johnson’s behavior, while susceptible of an innocent explanation–Johnson may have simply been trying to put his wallet away–might also have been reasonably viewed as an attempt to conceal a weapon and/or other contraband material, such as narcotics, from a police officer who had just appeared on the scene. See Arvizu, 534 U.S. at 277 (”A determination that reasonable suspicion exists … need not rule out the possibility of innocent conduct.”). When combined with the fact that Johnson was engaged in such behavior in an area known for criminal activity and on a street where a crime-related homicide had recently occurred, Officer Shaughnessy’s observations provided a sufficient basis for temporarily detaining Johnson to determine whether or not he was actually engaged in wrongdoing. ,,,

Opinion, p. 6. The holding does seem to limit itself, however, by noting that 1) Johnson was in a high-crime area, and 2) in a high crime area where a crime had just occurred. At least arguing from the defense’s perspective (which, after all, is what I do), I would argue a limited holding based on the pre-existence of an immediately committed crime.