Bamboo is anisotropic like timber, which means that expansion and contraction caused by drying or temperature variation will happen at different rates along the tangential, longitutional and radial axis. Crack happens when stress exceed the tensile strength of the material in one direction. Thus a long and thin object is less vulnerable to this type of failure as only one axis undergoes a significant change in size.

In addition, the bamboo ski poles may have been thoroughly dried by kiln heating and sealed with some type of resin or lacquer to prevent moisture ingress, especially if they were made to get wet.