Every muscle in my body slackened like a broken spring and I was leaning against the side, of the box.

Her muscles slackened, as if she had been hit in the head; she nearly dropped her sword.

The iron-hard muscles of the arms that held him slackened.

The muscles of his jaw slackened enough for her to force the tiny wedge into his mouth.

He relaxed back in the chair, letting his muscles slacken for the first time in hours.

At last his muscles slackened and his movements grew less frenetic.

Already, his muscles had slackened, relaxing the pain of his seizure.

And once we were through it, muscles - around eyes, across backs - slackened perceptibly.

His straining muscles, freed from the terrible force, slackened, and he lay limply on the ground.

The pilots cautiously relaxed their grip and let their muscles slacken.