那些放高利贷的人派了打手去恐吓拖欠还款的商人。

The loan sharks sent ___leg-breakers to intimidate the businessman who defaulted on payments.

今天的登山训练简直是个断腿活，我现在连楼梯都爬不动了。

Today's mountain climbing workout was a real ___leg-breaker - I can't even climb stairs now!