ADJ. hard, powerful, strong | taut, tense, tight | cramped I walked up and down the aisle to stretch my cramped muscles. | tired | abdominal, arm, calf, facial, heart, thigh, etc. | skeletal
VERB + MUSCLE flex, tense He flexed his muscles, then set off to run. | relax Learn how to relax tense muscles. | stretch | build (up), strengthen, tone (up) | pull, tear I laughed so hard I almost pulled a muscle.
MUSCLE + VERB ache | clench, contract, stiffen, tense, tighten | go limp, loosen, relax, slacken | quiver, ripple, twitch His muscles rippled beneath his T-shirt as he worked. | control sth the muscles controlling speech production
MUSCLE + NOUN cell, fibre, tissue | group | disease, pain | contraction, relaxation, spasm, tension | tone
PREP. ~ in The muscles in my face tensed.