a batters - box mat 1 contains a pivot device 2 which is mounted within a pivot recess 3 . in a preferred embodiment the batters - box mat 1 is made of a flexible material such as rubber . in a preferred embodiment , the top surface of pivot device 2 is set at an elevation equal to the top surface of batters - box mat 1 . in a preferred embodiment , pivot device 2 comprises a circular device with ball bearing that rotates freely about an axis perpendicular to the surface of batters - box mat 1 . in a preferred embodiment , toeholds 4 are recessed into the top surface of batters - box mat 1 . in a preferred embodiment there is more than one toehold , to allow for different stances of baseball batters . the batters - box mat 1 can be used for both right hand and left hand batters . during training the batters - box mat 1 is placed in the batters - box , to the right or left of home plate according to whether the batter is right or left handed . the batters - box mat 1 is oriented such that the pivot device 2 is nearer the catcher and the toeholds 4 are nearer the pitcher . the baseball baiter stands on the batters - box mat 1 with his rear foot resting on the pivot device 2 and the front foot resting on a toehold 4 . the baseball batter practices pivoting his rear foot on pivot device 2 while swinging the baseball bat , in order to maximize effectiveness of body rotation and bat swing . although the preferred embodiment includes flexible batters - box mat other embodiments are possible using rigid or semi - rigid mat material . although the preferred embodiment includes pivot device with top surface set at al elevations equal to top of batters - box mat , other embodiments are possible using pivot device elevations below or above the top of batters - box mat . although the preferred embodiment includes pivot device with ball bearing , other pivoting mechanisms such as roller bearing or lubricated slide bearing are possible . although the preferred embodiment includes recessed holds , other embodiments are possible with raised toeholds , or no toeholds at all . although the preferred embodiment does not include a home plate or any means of supporting a baseball in a position to be batted by batter , other embodiments are possible that would include a home plate and / or support for a baseball in position to be batted . referring to fig3 , the pivot device 2 of the present invention comprises a top surface 6 , a bottom surface 7 , and a bearing surface 5 positioned between said top surface 6 and said bottom surface 7 . the bearing surface 5 will reduce friction between the bottom surface and the top surface 6 of the pivot device 2 such that the pivot device is capable of pivoting about an axis of rotation that is perpendicular to the top planar surface of the batters - box mat . the bearing surface 5 may be comprised of any means well known in the art for reducing friction between two surfaces . in a preferred embodiment , the bearing surface will comprise ball bearings positioned between two bearing surfaces or races . the bottom surface 7 of the pivot device 2 will comprise a releasable securement means 8 joined thereto . as used herein , the term “ joined ” encompasses configurations whereby an element is directly secured to another element by affixing the element directly to the other element , and configurations whereby the element is indirectly secured to the other element by affixing the element to intermediate member ( s ) which in turn are affixed to the other element . the releasable securement means 8 will hold the pivot device 2 firmly within the pivot recess 3 during use yet will allow the pivot device to be readily removed from the pivot recess to be cleaned or to be replaced . the releasable securement means may be comprised of any number of securement means well known in the art that will hold the pivot device within the pivot recess during use yet allow the pivot device 2 to be removed when needed . for example , the releasable securement means may be comprised of a hook and loop fastening system , releasable pressure sensitive adhesives , or other such systems . in a preferred embodiment , the releasable securement means 8 will comprise a series of “ teeth ” or spikes joined to the bottom surface 7 of the pivot device 2 . the teeth or spikes 9 will protrude from the bottom surface 7 of the pivot device 2 and will be capable of “ biting ” into the material ( amalgam ) of the batters - box mat 1 at the bottom of the recessed area 10 .