I was watching some comedy videos where the actors break character and start to laugh extremely hard. It made me wonder: why do we bend forward (to the point you can touch the ground if you started from a standing position) from laughter? It this universal or just a bodily expression that people have picked up on that feels physically compelling in some cultures?
Because when you laugh really hard, your diaphragm muscles contract, expelling air out. I know when I do it, my whole range of stomach muscles get really tight and small, which makes me double over if I’m not careful.