No muscles do not have a refractory period. If we did we wouldn't be able to even lift objects.
The brainest answer would be appreciated.
The uterus relaxes is muscles after being stretched open. When the baby is about to be pushed out, the uterus contracts many times until the baby is out of the female's body.
There was a time when we were very physically active, but now we rely on devices to do most of our work. The changes in our behavioral patterns and adaptations that are caused by these technological advances could prove to be the primary driving forces behind the next stage of evolution for our species.
