8.31m is really a mediocre result. I believe even white long jumpers have achieved 8.50 and 8.60 jumps.
While "White men can't jump" is clearly a stupid racist statement and the movie with that title must be incredibly trashy, there is apparently a scientific base to the claim that athletes of west African decent have a small physiological advantage for sprint running and long jumping. The advantage in probably in the range of 1-2%, which translates to 0.1-0.2 seconds in 100m run, and 8.5-9.5 cm in long jumping.
When it comes to vertical jumps, Africans don't seem to have an edge over white. My guess is that their heavier bones and heavier muscle mass negates any advantage they have in explosive power output.
Now let's talk basketball. As anyone who follows this sport knows, this is a sport of statistics and averages, and the best team will always lose some of it games during the season and come close to losing in others. I actually watched most of the game of the USA vs. Lithuania and it was clear the Americans were better and in the last 5 minutes they upped their game and closed it. Lithuania is a very strong team and they came highly motivated and prepared while the Americans came to the game with over confidence and probably after too much partying and binging.