Given the right circumstances, repetitive stress like bending, lifting, throwing, running, and jumping can cause a bone to weaken and eventually break. Just think of bending a paper clip back and forth. Shins, feet, pelvis, and hips are where stress fractures usually show up, but they can also occur in the spine. When this happens, it’s called spondylolysis. Many times, people don’t even know they have one or if they do, treatment is very simple and effective.
Line Drawing Animated Video of Spondylolysis