The study was carried out in the José Silfo Alvan Del Castillo Fluvial port, better known as Masusa port, the main river port for embarking and disembarking passengers and merchandise in the city of Iquitos, in the Loreto region. In the port of Masusa, the loading and unloading of any type of merchandise is carried out mostly with physical effort in which many people who are called freighters (chaucheros) intervene daily. These informal stevedores work daily in unsafe conditions, they exert themselves on a daily basis when handling different heavy goods, associated with the lack of adequate equipment and implements, with forced postures, which is a predisposing factor to poor effort and the appearance of muscle injuries skeletal. The country lacks adequate legislation specifically for cargo stevedores in river ports and based on the adaptation to current national legislation, it seeks t...