The sit-up is an abdominal strength training exercise commonly performed to strengthen the abdominal muscles. It is similar to a crunch (crunches target the rectus abdominus and also work the obliques), but sit-ups have a fuller range of motion and condition additional muscles. Sit-ups target the hip flexors, rectus abdominus and also work the ili... Found on http://en.wikipedia.org/wiki/Sit-up
noun an stomach exercise in which a person sits up from a supine position without using the arms for leverage Found on https://www.encyclo.co.uk/local/20974