I did a lot of writing about sports and outdoors for years before snapping out of it. Looking back on it, I made more money and got more checks by writing in non-sports magazines.
Sure Young Athlete and such gave me bigger checks, but how often? I did almost as well at the deaprtments of Science (Orienteering, dynamics of a curve ball...that sort of thing.) Few sportswriters target them, so it was wide open. Same goes for inflight mags.
But my main sports bread and butter was columns in regional mags and community newspapers. At one time I had three regular columns on outdoor sports that added up enough to pay the rent.
As with ANY breakin plans, I recommend canvassing what's around you, perhaps even selling them on a column they don't yet have.
PS...for several years I had a weekly column forecasting the next opponents of the local college teams. How? I wrote to athletic departments of the schools, got their press guides, and converted their info into my own style.