I recently bought an Xbox 360 with Kinect and now my girlfriend really wants one of the dancing games (e.g. Just Dance 3 or Dance Central 2). I'ld be happy to buy her one of those games but my concern is whether or not she will be able to play it. My Kinect sensor is only able to see the top half of the body so I'm not sure if she can actually play it. Does the dancing games for the Kinect track the movements of the legs?
My wife has Dance Central for the Kinect, and it does track your entire body. Leg movements are involved in practically every dance routine. For us, the couch is around 6' from the TV in the Xbox 360 room, and we have to push it back about another 2-3' in order for her to have enough room to dance.
As a more "real world" test, if you have Kinect Adventures, (which is likely since it's typically the pack-in title for the Kinect) and the game complains that you're not far enough away for "2 player play," you probably don't have enough room.
Judging from videos I've watched, and seeing that it tracks movements of arms and legs, and the below part directly from Dance Central's support site, I would say that Dance Central requires your whole body to be visible.
How far should I stand back from the Kinect sensor?
Get noticed! Don’t stand too close to the sensor, or too far away. 6 feet is ideal. Once you’re visible from head to toe in the helper frame, you’re good to go.
Disclaimer: I haven't played Dance Central, nor do I have a Kinect.