Is it bad to bend your knees on chins? I am happy because now I can do decent sets of REAL ones from dead hang! Today I did 41!!! (5x4 and then 7x3). BUT my bar is just a bit short and so what I do is bend my knees a bit. I find also that on the last reps when I'm really struggling my knees start to come up toward my chest as I pull. I still focus on bringing my chest right up to the bar though.
Is it bad to bend knees? Should I be maintaining a straight plank with my body?