Sport & ContestGreek → English
Isotonic
/ˌaɪsəˈtɒnɪk/adjective
Having the same osmotic pressure as body fluid, or describing a muscle contraction that shortens under a constant load.
The Greek roots
ἴσος
ísos
equal
τόνος
tónos
tension, pitch
Literally: “of equal tension”
The story of the word
τόνος is the tension of a stretched string, from τείνειν, to stretch, which is also how it came to mean pitch and then tone. Physiologists use the compound in two senses, one about solutions and one about muscles. Sports drinks claim the first: matched to blood, so the gut empties them fast, which is why they taste faintly of salt.
- How it travelled
- Ancient Greek → scientific coinage → English
- First recorded
- 19th century
Same family
tonicmonotonousisobarisometric
In a sentence
An isotonic drink after a long ride does more than water alone.