His legs refused to support him, and he collapsed to the floor.

I wished to run to the window and call for help, but my legs refused their office.

Her legs, on which she hadn't called often these past two days, had taken to that state of affairs and simply refused to function.

He did, just before his legs refused to hold him.

Finally, he fell, his legs refusing to hold him up any longer.

Paul wanted desperately to back away as she came towards him, but his legs refused to move.

She told herself to step away, but her legs refused to move.

Niall tried to stand, but his legs refused to support him.

His legs refused to support him and he fell down, dazed.

He tried to move forward, but his legs refused the order.