noun Date: 1938 a conditioning exercise performed from a supine position by raising the torso to a sitting position and returning to the original position without using the arms or lifting the feet
SIT-UP
Meaning of SIT-UP in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012