The ornamental design for an exercise apparatus, as shown and described.
FIG. 1 is a front isometric view of an exercise apparatus of the present invention, with the broken lines defining the bounds of the exercise apparatus and forming no part of the claimed design;
FIG. 2 is a rear isometric view of the exercise apparatus of FIG. 1, with the broken lines defining the bounds of the exercise apparatus and forming no part of the claimed design;
FIG. 3 is a front view of the exercise apparatus of FIG. 1, with the broken lines defining the bounds of the exercise apparatus and forming no part of the claimed design;
FIG. 4 is a left elevation view of the exercise apparatus of FIG. 1, with the broken lines defining the bounds of the exercise apparatus and forming no part of the claimed design;
FIG. 5 is a rear elevation view of the exercise apparatus of FIG. 1, with the broken lines defining the bounds of the exercise apparatus and forming no part of the claimed design; and,
FIG. 6 is a top view of the exercise apparatus of FIG. 1, with the broken lines defining the bounds of the exercise apparatus and forming no part of the claimed design.
The right elevation view of the exercise apparatus of FIG. 1 is a mirror image of the left elevation view.