I don't have any friend here who can help me with English!My idea is hard to explain and on my mother language!
I will try to make things clear!
My idea is:
When we try(ing) to maintain wide arc from the beggining to the end and on way down,like on diagram shorten MA - thinks are good!
But it somehow not allow to us to keep fully extend the arm (in elbow joint)!
If you try to extend fully arm like in Barbell Curl (standing) Start Position and try to keep arm extend (only in elbow join) and try to curl this way....
YOu will see from begin you have straight way up after it arc!
My idea is:
Secound way keep more tension on the biceps because try to keep biceps extend long time,but it not allow to us to get Great Full Arc!
I don't know how to explain it more clean sorry
I make two pictures:
1) Is How Must Be
2)What happen if we staright with fully staight arm and trying to keep arm extend when curling!
It's good to consider and try different things. For example your earlier question before about whether to hold the weight out from the forearm or closer in would effect where the resistance lands and degree of difficulty.
Some of what you write is just slightly beyond comprehension; see if you have a friend you can send it to, to help clarify some of the english. As far as wide arcs or not, unclear what you're getting at.