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Low back pain (LBP) is one of the most important health issues among rotary–wing aircrews. The flight sitting posture and vibrations produced by the aircraft are identified as high risk factors for LBP.


July 29, 2009
By Emily Roback B.Sc. D.C.

Topics

Low back pain (LBP) is one of the most important health issues among rotary–wing aircrews. The flight sitting posture and vibrations produced by the aircraft are identified as high risk factors for LBP. The primary causes of LBP include steady mechanical vibrations, poor posture, lack of abdominal stability, loss of flexibility and poor health/fitness levels. With this in mind, an aviator experiencing LBP while controlling an aircraft comprises flying safety. Until recently, there has been an increase in the number of pilots reporting difficulties concentrating during flights as well as achieving low back and leg comfort while airborne in a helicopter.

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 An aviator experiencing low back pain while controlling an aircraft compromises flight safety.


According to Nigel Day, safety officer at Mustang Helicopters Ltd. in Red Deer, Alta., the incidence of lower back and right-sided sciatic pain in helicopter pilots (HP) is attributed to the steady horizontal and vertical vibrations and the in-flight pilot’s posture. Helicopter vibration has a peak power at frequencies around 5 Hz, which is within the range that the human upper body presents resonance frequency. Furthermore, there are several contact points between the pilot and the aircraft; hands, feet, low back and pelvis regions. The lumbopelvic (low back and pelvis) region accepts all horizontal and vertical forces. The horizontal forces are shear and the vertical forces are compression. With this in mind, this region is under maximal strain and minimal support.

Awkward posture is also independently connected with the presence of LBP and sciatica. In some helicopter cockpits, the pilot must flex forward at the trunk and towards the left to operate the controls, what appears to be the predominant in-flight seating posture for most helicopter pilots. This asymmetrical posture during prolonged flights tends to lead to musculoskeletal fatigue and fatigue often leads to pain. An average flight is four to six hours with three or four landings to refuel.

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The lifestyle of an aviator is quite similar to that of an office worker. The special relationship of the extremities (arms and legs) with the abdominals is defined as core stability. The more stable the spine is, the easier it is to move the arms and legs effortlessly. The ideal positioning of the core involves aligning the extremities with the spine where minimal mechanical stress is applied to the soft tissues (i.e., muscles, ligaments, tendons, capsule, etc.), bones and joints. Incorrect alignment produces additional mechanical demands on the supporting structures and creates wear and tear in the joints. Also, improper positioning of the pelvis creates excessive anterior tilt (top of the pelvis rotates forward), which is common among pilots during prolonged sitting in aircraft.

 Prolonged unsupported sitting may also result in loss of flexibility in the hip joint and supporting muscle groups. The post-flight stretching routine must consist of exercises focusing on five important muscles groups, namely, the hip flexors (iliopsoas and rectus femoris), hip lateral rotators (piriformis), hip adductors (iliotibial band and tensor fasciae latae), hip extensors (hamstrings, gluteals, and calves) and upper chest (pectoralis major/minor). More often than not, pilots who do not stretch, find themselves constantly shifting their body in their seat to minimize low back and leg discomfort.

For a typical rotary-wing operator, practising good health/fitness habits is not considered a priority unless there is a decrease in operational effectiveness and quality of life. An increase in bodyweight, decrease in energy levels, and increase in joint wear and tear encourages the pilot to take more time off work and spend time at the doctor’s office. Flying a helicopter predisposes flight operators to low back pain and degenerative joint disease. It is important to not only perform specific stretches for the lower body, but also to progress to higher levels of exercise that include stability, muscle endurance/strength, power/agility, balance and co-ordination. By improving power, agility, balance and co-ordination, pilots have better eye/hand speed and co-ordination. An increase in muscle mass, vitamins/minerals, healthy food/beverage intake, and bone density, leads to higher metabolism and lower body fat percentages. As a result, aviators can handle the aircraft effortlessly and maintain good health/fitness levels.

Prevention is the best method for management of LBP induced by steady mechanical vibrations, poor posture, lack of abdominal stability, loss of flexibility and poor health/fitness levels. It is recommended to utilize cushions that dampen the effects of vibrations that occur in a single flight. Each time there is an opportunity to land the aircraft, do an extra set of stretches to extend the back and flex to the right side. While sitting for long periods, practise tilting the top part of the pelvis backwards and tightening up the abdominals for two minutes every 20 minutes. By practising good exercise techniques and good eating habits daily, you will automatically improve the overall quality of life and operational effectiveness. There will be a reduction in the number days taken off work, an increase in readiness, a decrease in wear and tear of the body, and a decrease in health-care and veterans affairs costs.



Emily Roback is a chiropractor with Chiroback Trekker, practising in Aviation Chiropractic. Her aviation patients have inspired her to pursue a mountain ski guide certificate and private pilot licence to work in the heli-ski industry. Dr. Emily Roback can be contacted at roback@doctor.com or 403-886-2044.


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