Hahaha, at first when I opened the thread I expected it to be about OUR movement, not baby's...
I find myself groaning and "umph'ing" and sometimes "ouch'ing" at every little bending, stooping over, sitting down, getting up, movement I do!
But I can sure relate to the baby movement being an ouch... yes they must like the feel of their hand, elbow, foot or knee as it works over the "washboard" that is my ribs...
OUCH!