Criss Cross Tumbling: Criss cross tumbling is a practice and optional meet warm-up pattern for tumbling floor exercise. Gymnasts line up in two lines in two side-by-side corners and take alternate turns tumbling along the diagonals like they do in competition. The pattern when seen from above is like an X or a cross (+), hence the name.
It is typical in optional meets to do criss cross tumbling for somewhere around two-thirds of the allotted practice time and then split out to various parts of the floor to work on dance. In practices in their own gym, gymnasts may also do criss cross tumbling as opposed to starting in a number of lines going from one side of the floor to the other, because the diagonals are 48 feet long and going from one side of the floor to the other is only 40 feet.
In Compulsory meets, gymnasts typically line up and go from one side of the floor to the other for both tumbling and dance in lines by team.