why did orlando warned by the ladies not to wrestle with charles?

Aperently Charles is a huge guy and a good wrestler with a pentiant for breaking ribs,

"The eldest of the three brothers wrestled with Charles, the duke’s wrestler. Immediately, Charles threw the brother, breaking three of his ribs; it’s not likely he will survive. Charles did the same to the second brother, and the third."

The main idea is that Orlando will be turned into a pretzil should he accept the challenge.