SPINAL SHRINKAGE DUE TO +GZ FORCES

Background: Fighter pilots frequently complain of inflight pain in the cervical or lumbar spine. As to the cervical spine, there is evidence that repeated exposures to high +Gz forces and inflight neck pain may cause premature cervical disk degeneration. Whether inflight lumbar p ain caused by high +Gz forces has a similar effect on the lumbar spine has not been studied. Hypothesis: The aim of the study was to investi gate whether high +Gz forces during aerial combat maneuvering reduces the body height. Investigation to determine whether any long-term dege nerative changes occur in the lumbar spine was beyond the scope of thi s study. Methods: The body height of 20 junior fighter pilots was meas ured before and after 30 min of recumbent rest and after high-G flight s. A special measuring device was used. Measurements were also made wi th the pilots sitting fully equipped in a fighter aircraft on the grou nd. Results: Maneuvering under high +Gz forces for 40 min caused a 4.9 mm decrease in body height. Recumbent rest before flights increased b ody height by 2.5-3.5 mm, and sitting in an aircraft returned body hei ght to the values measured before rest. Conclusions: The findings indi cate that +Gz forces place a high stress on the spinal column. Therefo re, the work of a fighter pilot can be considered to be physically dem anding with respect to the spinal column.