Knee pain and popping is a common problem and can be caused by a number of factors. Another term commonly used for popping in the knee is Crepitus, which essentially means a noisy joint, whether it be popping, clicking, cracking or snapping.
The final type of erosion is attrition. Attrition is a way of eroding the riverâs load, not the bed and banks. Attrition is where pieces of rock in the riverâs load knock together, breaking chunks of rock off of one another and gradually rounding and shrinking the load.
Attrition can also occur in glaciated regions, where it is caused by the movement of ice with embedded boulders over surface sediments. Pebbles are more affected by attrition further upstream, as the rivers' velocity tends to be higher, and therefore its competence (ability to carry sediment) is increased.s rocks are transported downstream along a riverbed, the regular impacts between the grains themselves and between the grains and the bed cause them to be broken up into smaller fragments. This process also makes them rounder and smoother.