最好先伸展一下僵硬的肌肉。It is better to stretch the tight muscles first.也许从背后已无法认出她的发胖僵硬的身子了.Perhaps her thickened, stiffened body was no longer recognizable from behind.他按摩着自己的胳膊和僵硬的双腿。He rubbed his arms and stiff legs....

“僵硬的”的英语可以翻译为：hard-shelled，inflexible，[医] spastic，rigid，renitent ...