[iironiic]

Sports don't necessarily have to focus on human's physical limits and constraints. Recently these days, it's common to accept activities like chess and poker as sports, where one develops a versatile strategy to attack and counter their opponent, just like most of the well known everyday sports.

Games like FFR, DDR and SM fall under the category of activities that requires no strategy against your opponent, just like bowling and track. We all develop many strategies to improve our performance on rhythm games, whether it be focus on the jumps, increase speed mod, etc., just like bowlers who (presumably) have a strategy for optimal game play. However, it is more apparent to realize that bowling requires a considerable amount of concentration just like rhythm gaming.

As a former track athlete, I am definitely confident to say that there is an optimal form of running and sprinting. This is where strategy comes into play in the case of track.

That being said, I would say rhythm gaming is a sport.

EDIT: tldr, strategy, concentration, and endurance are considerable factors in sports that many people don't realize. It's not only physical limitations.