title: Spinal shrinkage due to +Gz forces.
abstract: 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 pain caused by high +Gz forces has a similar effect on the lumbar spine has not been studied.
  
  
  OBJECTIVE
  The aim of the study was to investigate whether high +Gz forces during aerial combat maneuvering reduces the body height. Investigation to determine whether any long-term degenerative changes occur in the lumbar spine was beyond the scope of this study.
  
  
  METHODS
  The body height of 20 junior fighter pilots was measured before and after 30 min of recumbent rest and after high-G flights. A special measuring device was used. Measurements were also made with the pilots sitting fully equipped in a fighter aircraft on the ground.
  
  
  RESULTS
  Maneuvering under high +Gz forces for 40 min caused a 4.9 mm decrease in body height. Recumbent rest before flights increased body height by 2.5-3.5 mm, and sitting in an aircraft returned body height to the values measured before rest.
  
  
  CONCLUSIONS
  The findings indicate that +Gz forces place a high stress on the spinal column. Therefore, the work of a fighter pilot can be considered to be physically demanding with respect to the spinal column.
authors.affiliation: Air Force Academy, Kauhava, Finland.
authors.forename: O
authors.initials: O
authors.lastname: Hämäläinen
authors.forename: H
authors.initials: H
authors.lastname: Vanharanta
authors.forename: M
authors.initials: M
authors.lastname: Hupli
authors.forename: M
authors.initials: M
authors.lastname: Karhu
authors.forename: P
authors.initials: P
authors.lastname: Kuronen
authors.forename: H
authors.initials: H
authors.lastname: Kinnunen
mesh_terms: D000328:Adult; D000337:Aerospace Medicine; D001696:Biomechanical Phenomena; D001827:Body Height / Q000502:physiology*; D005387:Finland; D006801:Humans; D018471:Hypergravity / Q000009:adverse effects*; D008889:Military Personnel; D013131:Spine / Q000502:physiology*; D013314:Stress, Mechanical