Why do you feel so weak after cracking?

Anyone else ever wonder why its so hard to press on the pedals immediately after cracking, even when you could have probably gone at least a little longer if you hadn’t let off the pedals?

I am sure the mental aspect is big, but there has to be something physiological going on here.

Its all in the mind, even pain according to @chad is all in the brain as a protection system.

That explains why you can’t go after you’ve completely exhausted physically yourself, for sure. However, it doesn’t really explain the phenomenon of why you can’t go after giving up mentally when you physically had a little left in the tank.

Adrenaline wearing off?

I’m no expert but I I reckoned when you are moving at say tempo there’s enough oxygen in the blood to break up lactic acid. When you stop there’s no longer enough and the lactic acid starts to thicken :-/