1 to stay awake and not go to bed although it is late -- 遲睡，熬夜
I'll be late tonight, so don't sit up for (= wait for) me. 今晚我回來會很晚，所以不要熬夜等我。
[ + -ing verb ] The book was so interesting that I sat up all night reading it. 這本書太有趣了，我讀了一整夜。
3 a type of exercise in which someone sits up from a lying position, designed to make the abdominal muscles stronger -- 仰臥起坐
Most have simple instructions attached to them, and the stations include balance beams, sit-up bars, chin-up bars, parallel bars, and more challenging stations such as pole climbs and ladder walks.
This exercise is performed sitting on the floor with knees bent like in a sit-up position with the back typically kept off the floor at an angle of 45.
Soldiers are scored based on their performance in three events consisting of the push-up, sit-up, and a two-mile run, ranging from 0 to 100 points in each event.
The arm hang and the sit-ups, both tasks requiring a certain degree of muscular endurance, load on a third factor for boys and girls.
At the low end was a penny sit-up, where a homeless client could get food and shelter from the cold in exchange for a penny.
For example, the exercise are pull up, sit-up, barbell curl, standing calf raise.
The test consists of five items or stations: sit-up, standing broad jump, chin-up, 4 x 10 metres shuttle run, and 2.4 kilometres run.
It was like a penny sit-up except that a rope was placed in front of the bench.
