Hello Christian
I while back I saw your videos on Youtube and I was greatly inspired to do the same as you did 2 years ago. I am very skinny, I weigh 66kg and I am 1m86 tall which makes a BMI of 17+, which is not great to start with I suppose. Anyway, I started level 1 which felt great (without the pull exercises because I haven't got bar). I just have one problem, I have Poland Syndrome. I have no idea you heard of it but it means you miss certain muscles in your body when you are born because of failed bloodflow, in my case I miss my left musculus pectoralis major. This means push ups are extremely hard for me to complete (the correct form that is), so i thought you might have some other exercises for me to start and strengthen up my shoulders and back, so I can work towards completing the level 1 and 2 sets for push ups.
Thanks in advance!