It's an old sewing technique to prevent the thread tangles and the machine from un threading itself when you first start sewing. On old machines the take up lever just stopped where ever and if it was down when you stopped and you pull your project off the machine and cut the threads then when you started the next line of sewing the take up lever would go up and pull the thread out of the machine. Even with the take up lever in the up position you always had to hold your thread ends or you would end up with little birds nests on the bottom of your project.