That analogy sounds good on the surface, but breaks down quickly. In the context of sport/athletics it's your body doing the work, which is difficult to change without exercise (even with steroids). But for knowledge work, as long as you have access to the llm machine, you can quickly pretend it's your work. For students it can be very deceiving, they type their ideas on a device, one button fixes their spelling, another button "fixes" their wording. The line is very blurry, literally the divider in the UI between these two buttons.
This answer is obvious, however, video games/simulators can indicate if someone has potential.
Sim racing is a good example of this, there have been several drivers who went pro. Sims are used by racing teams and people like Max Verstappen, Lando Norris use sims heavily to improve their race craft.
I do a bit of sim racing and raced against pro drivers.
Athletic ability is a huge part but nearly every sport has a chess component. Additionally, ability to perform under pressure and dealing with stress/anxiety is another part of sports.
If I don’t exercise, will I ever become one?