DON'T DO THIS WITH YOUR BICEPS !!! (avoid injuries) 

Hi, you understood it well, but you don’t need to force anything, don’t force external rotation on planche and don’t force pronation, those are mobility that you need in your everyday life so that your body can feel safe using them, it won’t help you and worse it will put you in danger to go against natural position of your arm in planche, make sure you have enough of what I showed in the test, the rest should be ok, stay normal on planche

thanks for clarifying!

It doesn’t really produce an external rotation movement it’s relative motion rewatch the video but for helping you I can give you an example If you stand and you put your right foot forward, you didn’t move the left but in the end the left foot is in a backward position COMPARED to the right foot Same for shoulders Hope it helps ;)

Did I understand correctly that if you have bad external rotation mobility then you shouldn't do supinated planche or maltese stuff and if so is it most safe to have a neutral grip (not pronated or supinated) and not force external rotation? Also do you have any tips on improving external rotation mobility?