Determination of lumbar muscular activity in helicopter pilots: A new approach

Background: Discomfort in the lumbar region is a frequent complaint of heli copter pilots. Two factors that helicopter crewmembers relate to back pain are exposure to vibration and poor posture during flight because during fli ght the seat and controls force the pilot to adopt an asymmetric posture. R epeated exposure to these adverse flight conditions could cause pathologica l changes in the spine. The purpose of this study was to compare right and left sided lumbar muscular activity in helicopter pilots under real flight conditions, using surface electromyography (SEMG) to demonstrate the effect s of asymmetrical posture on the musculoskeletal system. An attempt was als o made to correlate lumbar muscular activity with environmental factors and such variables as type of flight, type of helicopter, duration of fight, a ge, physical fitness, and height. Methods: Right- and left-sided lumbar ele ctrical activity were measured using two-channel SEMG during 35 flights in 2 types of helicopter and a cockpit mock-up. Results: There was a statistic ally significant increase in right-sided lumbar activity when related to th e duration of flight. Conclusions: The data showed that when the pilot used the manual controls during flight, he did not maintain a symmetrical postu re and contracted one side more than the other. We think the relationship b etween the greatest right-sided contraction and flight duration is due to m aintaining an asymmetric posture over a long period. We also noted a tenden cy towards greater right lumbar musculature activity in older pilots.