If you are a runner and you choose not to do any form of strength training then you are going to increase the chances of having to stop as you develop some kind of injury.Many runners that do not believe that lifting weights is crucial are sadly mistaken. In fact even though running itself may not actually cause an injury it does help to highlight any weaknesses that you have and which may prevent you from seeing any improvements taking place even though you may be running every day. There is no better way to determine what needs to be done to improve our bodies than by listening to it when out running and making changes.