I claim the ornamental design for an athletic shoe, as shown and described.
FIG. 1 is a right rear perspective view of my design for an athletic shoe showing a cutout in the rear of the shoe (the broken lines show the environmental structure and are not a part of the design to be patented).
FIG. 2 is a right front perspective view of my design.
FIG. 3 is a right side elevation view of my design (the left side elevation view is a mirror image of the right side).
FIG. 4 is a right side perspective view of my design.
FIG. 5 is a left side perspective view of my design.
FIG. 6 is a rear perspective view of my design; and,
FIG. 7 is a front perspective view of my design.
The bottom of the shoe is not shown and forms no part of the claimed design.