Assuming you were being sarcastic here, there is big difference between sprinter and basketball player. Sprinter relies solely on acceleration and power for a short distance and needs huge powerful legs for quick speed.
While a basketball player needs this for sprinting on fast breaks or accelerating down lane, he also has important endurance factor to account for- running almost nonstop for 40+ minutes a few times a week. This is where I think huge legs have a negative effect.
And also a negative effect on jumping....I mean look at the highest flyers over the years- never huge legs