To set limits on transform channels that will be animated, right-click the icon to open the Attribute Editor, and click the Limit Information tab under Transform Attributes. Setting limits on all the icons is necessary to make the character GUI sliders generate correctly later. If you don’t want to limit a particular control, then just set the limits on that icon to well beyond the normal values.
For instance, for an arm icon that will only be translated, setting a limit of 50 grid units on the translation channels will be more than enough to allow for a free range of motion on most normal sized characters. Or setting a rotation limit of 720 on the Char icon will allow the animator to completely turn the character twice, which is more than most scenes require.
for more info see: http://www.peachpit.com/articles/article.aspx?p=1311730
