Neck and back muscle loading in pilots flying high G(z) sorties with and without lumbar support.
BACKGROUND
Fighter pilots frequently encounter neck and back pain and injuries due to high G(z) loading. A lumbar support could diminish muscle strain in the lower back under G(z) loading and might also have a positive effect on cervical muscle strain, due to a more ergonomic sitting posture. The aim of this study was to determine the effects of individually adjusted lumbar supports on fighter pilots' neck and back muscle loadings.


METHODS
There were 11 Finnish Air Force pilots who acted as test subjects. They flew two basic air combat maneuvering sorties with and without the LS. The EMG activity of the sternocleidomastoid (SCM), cervical (CES), thoracic (TES), and lumbar erector spinae muscles (LES) were measured during these sorties, and the number and duration of EMG gaps was analyzed. Subjective experiences about the lumbar support were evaluated using a questionnaire.


RESULTS
In all measured muscles, mean percent maximal voluntary contraction (%MVC) was lower when the LS was used, yet these changes were not statistically significant. Individual differences in %MVC between flights diminished in the CES (9%), TES (7%), and LES (8%) with LS in use. There was also a tendency toward increased number of gaps in EMG activity when flying with the LS. According to questionnaire responses, the LS seems to relieve in-flight symptoms and reduce the fatigue in the lower back muscles. Not all subjects benefited from the LS, however.


CONCLUSIONS
There seems to be a tendency toward a lower muscle strain with the LS, but there are considerable individual differences.
Sovelius
Roope
R
Training Air Wing, P.O. Box 5, FIN-62201 Kauhava, Finland. roope.sovelius@mil.fi
Oksa
Juha
J
Rintala
Harri
H
Siitonen
Simo
S
D001359:Aviation; D004576:Electromyography; D006804:Ergonomics; D006801:Humans; D018471:Hypergravity / Q000009:adverse effects*; D008161:Lumbosacral Region; D008889:Military Personnel; D018482:Muscle, Skeletal / Q000293:injuries / Q000503:physiopathology*; D009334:Neck Muscles / Q000293:injuries / Q000503:physiopathology*; D009989:Orthotic Devices; D011187:Posture; D013180:Sprains and Strains / Q000209:etiology / Q000517:prevention & control*; D016474:Weight-Bearing / Q000502:physiology