I'm with KaptKaos (and Hemingway)
There are a lot of things out there that are called "sport" that are more "game".
The various off-road events like WRC and the Paris to Dakar events require physical and mental toughness.
ANd to me there is no question that off-road motorcycle enduro (certainly a "motorsport") is one of the most physically demanding activities I can think of.
I've run the "Meteor Enduro" and "The Sandy Lane Enduro" here in the northeast and let me tell you, I'd rather run a marathon!
The six-day ISDE motorcycle is one of the most challenging events on the planet. Try doing stuff like ~THIS~ for six days.
And the Alligator Enduro down in Florida is a famously tough one (see below).
I'd also say that from my very mild, entry-level experiences that ~Flying Aerobatics~ is physically tough and requires committment...and I'd say it's a motorsport.
Basically, now that I'm old, I've "retired" to vintage car racing and very mild aerobatics...much easier! 
I've done 3 hour enduros solo in my Spridget.....that is physically demanding and requires a lot of focus. I'd call that more a "sport" than a game.
I have an MGB I take to car shows after I polish the fenders. That is NOT a sport. 