An exercise in which the abdominal muscles are contracted, bringing the torso of a person lying down to a more upright position
Susan's doing sit-ups to stengthen her muscles.
An stomach exercise in which a person sits up from a supine position without using the arms for leverage
sit-up sit-ups in AM, also use situp Sit-ups are exercises that you do to strengthen your stomach muscles. They involve sitting up from a lying position while keeping your legs straight on the floor