Etymology
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amyotrophic lateral sclerosis (n.)

sclerosis of the spinal cord, causing atrophy of the muscles, 1874, in translations from French. Amyotropic is compounded from Greek elements: a- "not, without" (see a- (3)) + combining form of mys "muscle" (see muscle (n.)) + trophikos "feeding," from trophe "nourishment" (see -trophy). Also ALS, and often known in U.S. as Lou Gehrig's disease, after the New York Yankees baseball player who was diagnosed with it in 1939 and died of it in 1941.

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beef up (v.)
"add strength," 1941, from college slang, from beef (n.) in slang sense of "muscle-power" (1851).
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