i recall being pretty amp'd on my best jumps/dunks.
i've had some great relaxed jumps, but my best jumps were all very aggressive.
"aggressive & loose" vs "aggressive & tight": sometimes you do get some incredible performances when you aren't trying as hard. ie look at T&F events, where someone's early jump/throw could be their best. more "relaxed" could be an observation. potentially more efficient nervous system, relying more on programmed motor patterns instead of trying to force them etc. i imagine there's some kind of fine line/groove that each person has to figure out. could be a little different between some folks.
pc!