Permanent changes in the spines of military parachutists.

To investigate whether parachuting causes permanent changes in the spine, 50 military parachutists (mean number of jumps 490 per parachutist) and 50 matched controls were studied. In X-rays of parachutists and controls, the frequency of degenerative changes differed in the cervical spine (46 and 20%; p less than 0.01), and in the thoracic spine (62 and 28%; p less than 0.05) but not in the lumbar spine (44 to 36%; not significant). Parachutists suffered significantly more often from stiff neck, but the incidence of other neck and back symptoms was the same in the two groups. The increased frequency of degenerative changes in the spine in military parachutists is probably due to repeated traumata which parachutists sustain on landing and, possibly, during the training period before parachute jumps.