I've been working out for about 14 months.
This is because I have a disease called pectus excavatum, a medical term.
My personal workout is to improve my dented chest to be well-shaped.
You might think it seems so normal compared to how people do their workouts, but it is certainly effective, referred to as a method of expanding your rib cage.
Here is a Japanese website spelling out the method.
【胸郭を広げる方法】
胸郭を広げ胸囲100cmはおろか110cmになるための特殊な筋トレ方法を解説します。分厚い胸板と100cmを越えるサイズの胸囲は男性にとって憧れですが、筋トレで大胸筋を鍛える以前に、その筋肉が乗る土台作りとして「胸郭を広げるトレーニング」が重要なのをご存じでしょうか?
Since I have seen this site, I have been doing it.
But these days, the way I do has completely become a normal one, so I have to go back to the right way.
My pectus excavatum surgery record is here.
I have felt my chest is getting a good shape thanks to this way, and I am also in good shape.
Many who have this disease tend to be bony, so I try to get out of this.
I'll keep on working out every day.