I'm trying to find experimental evidence that confirms diaphragmatic spasm is the cause of inspiratory apnea after a person gets winded (blow to the upper abdomen). Amazingly, this appears to have never been studied.
I'm concerned that "being winded" can indeed lead to prolonged respiratory arrest and death in certain types of blunt trauma including low-velocity hits to the chest too ("low" as in, say not from a car accident). Also, diaphragmatic rupture, the most extreme case of this type of injury can be fatal. Problem is, death would be imminent so studies could never confirm this... unless experimental... but that's a little too much.