Everyone’s bodies are different and every type of training is different. People train for the same sports differently and have different physiques to show for it.
Both of these women are Olympic class champion weight lifters, both won gold in the 1999 Winnipeg PanAm games in their respective weight classes.
So many factors need to be considered, there’s no single “yes train at an undisclosed sport for ten years and you will absolutely have this one body type”. Is your character naturally an endomorph, ectomorph, or mesomorph? Because that hugely influences their body type at any fitness level. Is your character living in the woods and hunting for food? because if that’s the case they won’t be getting as many carbohydrates (or really nutrition in general) as characters living in walking distance of a grocery store and would likely develop a leaner, scrappier physique than they might have otherwise. Are they actively trying to achieve a certain body type or do they just care about training to be better at whatever this one sport you haven’t told me is. Are they focusing on getting bigger? Stronger? More agile? Faster? More Stamina? Even then, that’s just a starting point to help you research and gather references, there’s no be-all-end-all cookie cutter body type for a given sport.
For the asker, here is something to consider for one of those specific training possibilities! If it’s pure strength your character is after, without attention to looks, then SOME body fat is actually going to be an inevitability.
You can’t build additional strength/muscle in a calorie deficit, except under very specific circumstances (very fresh beginners chewing through excess body fat stores as “free” extra calories, steroid use - and even then!) So what a lot of the “ripped” guys do is alternate heavy training with an abundance of calories (see: “Gallon Of Milk A Day”), including the fat gains that results in, with calorie deficit periods to “cut” the fat and training designed to retain as much of their hard-won lean mass as possible (going home to a can of tuna and crying). Getting ripped, in short, is a time-consuming pain in the ass.
See also the difference between this bulk/cut fitness fella:
(Martin Berkhan of Lean Gains)
And this slab of man-beef, capable of a 900lb deadlift and a 705lb bench press:
(Strongman Nick Best, a liftbigeatbig.com athlete.)
Not to say that Martin isn’t strong, but he also values a very lean physique and puts the time in to attain it. For someone like Nick, it would detract from his training for pure strength - and despite what his BMI would probably indicate at a glance, I’d say it’s more likely than not that he IS healthy. A heavier character is not always going to be in poor health - someone who lifts as heavy as Mr Best likely has a heart like a horse.
Great further elaboration on this topic.