Define Sit and Reach Flexibility component in the humans?

The subject sits on a mat with legs extended straight ahead. Legs should be at right angles to a taped the r box, with feet flat against a box with a ruler on top of it.  Keeping the knees straight, the subject slowly tries to reach forward, extending both hands as far forward as possible, momentarily holding the position. The length of the stretch is measured in centimetres at the fingertips. Pa3 the toe line is a positive reading. Not reaching the toe line is a minus reading. The flexibility score is the best of three attempts. This test is simple to administer but measures only hamstring flexibility. For this test, a testing box or flexomeasure and a yard stick is required.