I like people's attempts to step outside the question, but playing along...

LW-rationalists value thinking for yourself over conformity. A LW sport might be a non-team sport like fencing, a team sport in which individuals are spotlighted, like baseball, or a sport that presents constant temptation to follow cues from your teammates but rewards breaking away from the pack.

LW-rationalists value cross-domain skills. A LW sport might involve a variety of activities, like an n-athlon, or facing a quick succession of opponents who all trained together so that lessons learned against one are likely to apply to the next.

LW-rationalists value finding ways to cooperate with people whose values are different. A LW sport might involve a tension between behavior that supports the team and behavior that wins personal glory, like basketball, or it might involve more than 2 sides and more than 1 winner with potential for cooperation.

LW-rationalists value an ability to recognize when a previously useful heuristic isn't working, and break out of it. A LW sport might involve subtle shifts in the playing field that weaken some strategies and strengthen others.