"Tha's right. It's when your muscles don't need to do as much as they used to, so they basically start eatin' themselves. In adults it ain't too bad - if you work out you can keep your muscle mass up - but in kids it can be deadly. Raisin' children in space means they never gain the musculature needed for their bodies to work under gravity. And if we don't keep up with our exercise, it can be pretty damn painful for us, too, anytime we're in high gee."

At her question, he frowned a bit.

"Accepted form? Of fighting, you mean?"