How relaxed the throwing arm should be?

Should the arm be like, noodle loose? I have been confused by this subject lately… I’d like to see some scientific explanation to verify its credibility

At what point in the delivery are you talking about?

High-cocked position and ball release.

it all depends on the person. i just keep my arm loose liek a jelly, during all of it. for me it helps put no stress and it looks like the ball is exploding out of the arm. also b.c ur not all tense u have a greater chance of not having injury it is never good to keep ur arm tense n squeeze the ball tight