noun
sit-up exercise; abdominal exercise
Refers to the exercise itself, often used in fitness contexts. Can be used for a single sit-up or the exercise in general.
毎朝、腹筋運動を30回やっています。
I do 30 sit-ups every morning.
腹筋運動は腰痛予防に
Abdominal exercises are said to be effective for preventing back pain.