I know several healthcare professionals with permanently screwed up backs because a patient was falling and they went to catch the patient. Much like an I-beam falling on you, you don't always get to pick and choose what you have to deal with.

I asked a couple nurses I know and they have never heard of this "staff-to-weight" ratio. At least here in America most hospitals operate on staff-to-patient ratio. I suppose this could be different in other countries.