The questions you ask are the very ones a group of researchers in Germany studied. They took X-rays of 159 former track and field athletes (all males). They compared the results with the event each subject participated in.
Here's what they found: shot putters, discus throwers, and high jumpers had more bone spurs in the lower spine than any other field or track athlete. They also had low disc height in the lower spine.
Endurance athletes like the marathon runners seemed to have much less load on the low back. However, the marathon runners had lower disc height in the lumbar spine. Since there isn't a great deal of twisting and arching in this event, yet they had the same changes as the shot putters and jumpers, the researchers think there may be a strong genetic factor at play.