I'm a pretty casual overall football fan and a pretty dedicated Detroit Lions fan. I'll check the draft picks on my phone for the teams I care about, but I don't feel a need to watch paint dry. As a spectator I prefer lacrosse, rugby, combat sports (judo, jiujitsu. boxing, MMA) and strength sports (power lifting, crossfit*, Strong Man).
In high school I was pretty much a power athlete. Nose tackle in football, wrestled heavy weight, threw shotput and run the 100m dash. In my experience there was a good deal of crossover between us big dude athletes and general nerd culture. A lot of us played at least Magic, were into computer games, and comic books. A large portion of my D&D group in high school came from our defensive line and/or wrestling team. That might have been a bit of a chicken or the egg thing though.
As an adult I spent 4 years in the United States Army which got me back into weight training. As a commo nerd there were a lot of nerd adjacent folks who were still pretty focused on their physical fitness. My platoon sergeant at my first duty station in Suwon, South Korea got me back into World of Warcraft. Lot of Magic, computer games, and even a bit of D&D. Also lots of watching UFC fights.
After the Army I've kept active mostly through weight training, muay thai and jiujitsu. I tried Crossfit, but it's not my thing. There's a pretty big nerd intersection in both the power lifting and jiujitsu spaces. They both really benefit from an analytical approach to training. Joe Rogan has even talked about the rise of the nerd assassin in jiujitsu. Really smart dudes taking over the space.
* Not a fan of crossfit as a training modality, but really enjoy it as a spectator sport.