For Michelet, the Renaissance was more a development in science than in art and culture. He asserted that it spanned the period from Columbus to Copernicus to Galileo; that is, from the end of the 15th century to the middle of the 17th century.
Other researchers believe that side stitches are caused by stretching the ligaments that extend from the diaphragm to the liver. When a runner or walker pounds the surface while breathing in and out, he or she stretches these ligaments, and that causes the pain.
There are two main causes of shin splints. The first is the excess of impact to the lower legs, which is primarily created by heel striking. The second main cause is overuse of the lower legs while running. Overuse injuries primarily happen when you push off with your toes to propel yourself forward.