A note to the mechanical principle in carrying with shoulder-pole

Shoulder-pole as a tool for carrying objects is widely used in China. As an elastic cantilever, it may make the load vibrate vertically for the shoulder up and down in the gait cycle. On the other hand, the carrier’s velocity changes periodically for he goes by feet alternately, which causes swing of the objects hanging with rope on the pole ends. Therefore the force acted on the shoulder-pole by the rope changes periodically, of which the vertical component may be amplified by the vibrating of shoulder-pole. A good shoulder-pole means that the carrier can take the step forward when the force on his shoulder is lower.