Inquiry Regarding the BMLhandball Dataset in the AMASS Collection

[minjung98]

First, please understand that this is not a question about the code, but rather about the data itself.

I would like to know the specific meanings and differences between "Trial_upper_left", "Trial_upper_right", "Trial_upper_left_right", and "Trial_upper_right_left" in BMLhandball dataset. Additionally, I would appreciate it if you could explain what the numbers like 177 in "Trial_upper_right_left_177_poses" represent.

I have searched through web documents but couldn't find accurate information, so I am posting my question here to ask for your help.
Thank you.