For one, a basketball player is normally 6+ feet tall, so a 25 inch thigh on him will loo smaller than a 25 inch thigh on a 5'9 guy. Strength does not mean your powerful, but powerful could be strong, the definiion of power is power=strengthXspeed so basically power is explosiveness. Just cuz two people are identical in height, weight, and strength doesnt mean they are equally powerful. One could squat 315 in 1 second down, 1 second up BOOM done. The other may be a slow 3 second struggle down and a long pausing 5 second war up. Who do you think will jump higher?
This being said, theres some things you can do 1)never listen to this trainer for any advice again 2) begin preforming compound and olympic style movements with an explosive upward phase 3)find a good plyometric plan and 4) never ever burn muscle off intentionally