19023
MATERIALS / METHODS : Eighty girls from 10 . 7 to 18 . 0years old ( mean 13 . 83 +/- 1 . 97 ) were recruited : 20 artistic gymnasts ( AG ; high - impact activity ) , 20 rhythmic gymnasts ( RG ; medium - impact activity ) , 20 swimmers ( SW , no - impact activity ) , and 20 age - matched controls ( CON ; leisure physical activity < 3h / wk ) .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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