My knees weakened and I braced myself against the wall.

Her knees weakening, she sat back down on the bench and watched the people.

His knees weakened suddenly, and he had to catch himself on the door.

She felt his knees weaken, but he managed to keep standing.

The blood suddenly rushed to Kelly's face and she felt her knees weaken.

As my knees weakened I could only demand to see the manager.

Her knees weakened in relief, and she leaned against a wall.

As if his knees had weakened he sank slowly to the floor, taking her with him.

He felt his knees weaken and sank onto the ice.

Again her knees weakened and she reached out to brace herself.