Muscles strengthened by planking (3)
I believe the answer is:
abs
(Other definitions for abs that I've seen before include "Exercise to improve these" , "Some musculature" , "ratings?" , "stopping system" , "Stomach muscles (abbr)" .)
I believe the answer is:
abs
(Other definitions for abs that I've seen before include "Exercise to improve these" , "Some musculature" , "ratings?" , "stopping system" , "Stomach muscles (abbr)" .)