The ornamental design for a boxing-based fitness platform, as shown and described.
FIG. 1 is a perspective view of a boxing-based fitness platform, showing our new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a right view thereof;
FIG. 5 is left side view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The characteristic feature of the design resides in the overall appearance of the article.
The broken line showing of a boxing-based fitness platform is included for the purpose of illustrating portions of the article and forms no part of the claimed design.