Military Helicopter Pilots Research Articles

Cervical Disc Displacement in Military Pilots.

Cervical disc displacement (CDD) may disqualify pilots from flying and have a profound impact on military unit capability. The objective of this retrospective database review is to characterize the incidence and demographic predictors of symptomatic cervical spine disc displacement in pilots of fixed- and rotary-wing aircraft and ground-based controls. The Defense Military Epidemiology Database was queried for first-occurrence ICD-9 code 722.0: CDD cases from 2007 to 2015. Injury count rates among aircraft groups and overall incidence per 1,000 person-years were calculated and standardized for age, gender, and military rank, and 95% confidence intervals (CIs) were compared to determine significance. There were 934 new cases of CDD among active duty U.S. Military pilots during the study period. The overall incidence of CDD in all pilots during this time frame was 2.715 per 1,000 person-years (95% CI, 2.603-2.830). Helicopter pilots had a significantly higher incidence compared to all other aircraft pilots and crew at 3.79 per 1,000 person-years (95% CI, 3.48-4.13). This finding remained statistically significant after standardizing for age, gender, and rank. Among all military officers, increasing age was a risk factor for CDD. The U.S. Military helicopter pilots have an increased risk compared to fixed-wing pilots and non-pilot controls. CDD remains a rare, though career-threatening, condition. Increased education and awareness training are warranted for both helicopter pilots and flight physicians to recognize signs and symptoms of cervical pathology. Continued investigations into preventive measures to minimize injury and time unfit for flight are warranted.

Helicopter Pilot Performance and Workload in a Following Task in a Degraded Visual Environment.

BACKGROUND: In this study, we investigated the impact of a loss of horizon due to atmospheric conditions on flight performance and workload of helicopter pilots during a low-altitude, dynamic flight task in windy conditions at sea. We also examined the potential benefits of a helmet-mounted display (HMD) for this specific task.METHODS: In a fixed-based helicopter simulator, 16 military helicopter pilots were asked to follow a maneuvering go-fast vessel in a good visual environment (GVE) and in a degraded visual environment (DVE). DVE was simulated by fog, obscuring the horizon and reducing contrast. Both visual conditions were performed once with and once without an HMD, which was simulated by projecting head-slaved symbology in the outside visuals. Objective measures included flight performance, control inputs, gaze direction, and relative positioning. Subjective measures included self-ratings on performance, situation awareness, and workload.RESULTS: The results showed that in DVE the pilots perceived higher workload and were flying closer to the go-fast vessel than in GVE. Consequently, they responded with larger control inputs to maneuvers of the vessel. The availability of an HMD hardly improved flight performance but did allow the pilots to focus their attention more outside, significantly improving their situation awareness and reducing workload. These benefits were found in DVE as well as GVE conditions.DISCUSSION: DVE negatively affects workload and flight performance of helicopter pilots in a dynamic, low-altitude following task. An HMD can help improve situation awareness and lower the workload during such a task, irrespective of the visual conditions.Ledegang WD, van der Burg E, Valk PJL, Houben MMJ, Groen EL. Helicopter pilot performance and workload in a following task in a degraded visual environment. Aerosp Med Hum Perform. 2024; 95(1):16-24.

Relationship between Total Flight Hours and Individual Factors with Low Back Pain in Indonesian Military Helicopter Pilots

Introduction: Helicopter pilots are potentially at risk of Low Back Pain (LBP) and are twice as likely as fighter pilots to experience it. Helicopter pilots’ LBP is caused by a combination of risk factors: engine and rotor vibration, ergonomic risks due to cockpit design, static seating position due to operations, and individual factors. These factors are incorporated into cumulative aviation risk exposure, which can be measured by total flight hours. The prevalence of LBP in Caucasians is high, at 50.5%-92%. However, there has not been any research on Indonesian military helicopter pilots who have a different posture from Caucasians.Objective: To determine the prevalence of LBP, to analyze the relationship between total flight hours and individual factors (age, height, BMI, exercise habits, and smoking habits) with LBP in Indonesian military helicopter pilots.Methods: The study was conducted at the Indonesian Army and Indonesian Air Force with total sampling method as many as 124 people. An explanation was carried out followed by filling in the consent to become a research subject, filling in personal data, anamnesis, Numeric Rating Scale (NRS), physical examination, neurological examination, and total flight hour data.Results: There were 124 subjects, consisting of 37.9% pilots and 62.1% copilots, 87.9% of pilots operate large helicopters, have average total flight hours of 450 hours, age of 30 years, the height of 172.66 cm, low intensity exercise habits of 61.3%, and smokers as much as 45.2%. A total of 57 people (46%) experienced LBP. Statistical results showed that total flight hours had an association with LBP (p = 0.035) where each 1 unit increase in total flight hours had a 1.02 times greater chance of LBP.Conclusion: The prevalence of LBP is 46% and there is an association between total flying hours and LBP in Indonesian military helicopter pilots.

METHOD OF EVALUATION OF MILITARY HELICOPTER PILOT SELECTION CRITERIA: A NOVEL GREY SWARA APPROACH

Helicopter is a very important defence and attack tool for a country’s armed forces (army) (air force). With the rapid progress of technology, the designs of helicopters, the hardware and software elements in the helicopter have also been renewed and developed in parallel with advanced technology. Therefore, it is expected that the pilots who will use helicopters, which are an important flight tool of armed forces, will also have the qualifications to provide the necessary knowledge, skills, and criteria. The aim of the study is to determine the military helicopter pilot selection criteria and to find the importance levels of these criteria. For this purpose, three main criteria as “Health”, “Psychomotor” and “Education and Training” and thirteen sub-criteria were determined. The weights of the determined criteria were found by the Grey SWARA method, which is a current multi criteria decision making tool. According to the results of the analysis, it is found that the most important sub-criteria was “Practical Training”, while the lowest important criteria was the “Height and weight limits” criterion. With this study, the weights of the military helicopter pilot selection criteria were found for the first time with the Grey SWARA method.

Protective effect of helmet gentex hgo-56/p on hearing loss among military helicopter pilots

Aviation noise represents an important hazard for hearing loss among military pilots as they are continuously exposed to excessive noise during flight operations. Modern military aircraft, due to their maneuverability and tactical capabilities, require increasing engine power, while noise protection is limited only to the personal protective equipment which protects to a limited extent. Previous generations of helicopter pilots in the Croatian Air Force (CAF) used GSSH-A-18 headphones, whereas Gentex HGU-56/P helmets have been in use in CAF since 2004, primarily as mechanical protection for the head and secondarily to protect hearing. A study on hearing threshold measurements was performed on multi-purpose transport helicopter pilots who used headphones and helmets, respectively. The population of pilots who used GSSH-A-18 headphones had significantly higher hearing loss at higher frequencies, in the left ear, and in the speech area compared to the group using Gentex HGU-56/P helmets. The results of this study confirm the benefit of using of the Gentex HGU-56/P helmet to preserve the pilots’ hearing.

The fate of a Military Pilot in Malaysia: Lingering on the ground after young stroke

Strokes in young pilots can result in the devastating loss of productive years of life, especially for pilots at the peak of their careers. A 32-yr-old male military helicopter pilot was diagnosed with superior sagittal sinus thrombosis and bilateral parietal hemorrhages secondary to protein S deficiency after 15 years in military service. Two years post-stroke, he was carefully evaluated for a possible return to work after aeromedical assessment and the 1 percent rule being considered. A decision was made by the medical board for him to be disqualified to fly and grounded with work accommodation. The authors recommend that there is a need for reassessment up to two years using the objective PULHEEMS method for young pilots who failed aeromedical assessment due to stroke for returning to work as their experiences and knowledge is highly valuable.

Predicting Cervical Spine Compression and Shear in Helicopter Helmeted Conditions Using Artificial Neural Networks

OCCUPATIONAL APPLICATIONS Military helicopter pilots around the globe are at high risk of neck pain related to their use of helmet-mounted night vision goggles. Unfortunately, it is difficult to design alternative helmet configurations that reduce the biomechanical exposures on the cervical spine during flight because the time and resource costs associated with assessing these exposures in vivo are prohibitive. Instead, we developed artificial neural networks (ANNs) to predict cervical spine compression and shear given head-trunk kinematics and joint moments in the lower neck, data readily available from digital human models. The ANNs detected differences in cervical spine compression and anteroposterior shear between helmet configuration conditions during flight-relevant head movement, consistent with results from a detailed model based on in vivo electromyographic data. These ANNs may be useful in helping to prevent neck pain related to military helicopter flight by facilitating virtual biomechanical assessment of helmet configurations upstream in the design process.

A Model of Military Helicopter Pilot Scheduling

In this paper, we introduce a pilot's scheduling model which is able to maintain and balance their capabilities for each relevant skill level in military helicopter squadron. Flight scheduler has to consider many factors related pilot's flight information and spends a lot of times and efforts for flight planning without scientific process depending on his/her own capability and experience. This model reflected overall characteristics that include pilot's progression by basis monthly and cumulative flight hours, operational recent flight data and quickly find out a pinpoint areas of concern with respect to their mission subjects etc. There also include essential several constraints, such as personnel qualifications, and Army helicopter training policy’s constraints such as regulations and guidelines. We presented binary Integer Programming (IP) mathematical formulation for optimization and demonstrated its effectiveness by comparisons of real schedule versus model's solution to several cases experimental scenarios and greedy random simulation model. The model made the schedule in less than 30 minutes, including the data preprocessing process, and the results of the allocation were more equal than the actual one. This makes it possible to reduce the workload of the scheduler and effectively manages the pilot's skills. We expect to set up and improve better flight planning and combat readiness in Korea Army aviation.

The Effect of Physical Exercise Training on Neck and Shoulder Muscle Function Among Military Helicopter Pilots and Crew: A Secondary Analysis of a Randomized Controlled Trial.

Introduction: This study presents secondary outcome analyses, in terms of muscle function [i.e., maximal voluntary contraction (MVC) and rate of torque development (RTD)] from a parallel group, single blinded, randomized controlled trial introducing a physical exercise training intervention aiming to reduce neck pain among military helicopter pilots and crew-members.Methods: Participants (50 pilots, 58 crew-members) were recruited from the Royal Danish Air Force and randomized to either an exercise-training-group (ETG; n = 35) or a reference-group (REF; n = 34). Participants in ETG received 20 weeks of self-administered exercise training specifically tailored to target the neck and shoulder muscles. REF received no training. Outcome: (1) MVC was measured for cervical extension and flexion as well as shoulder elevation and abduction, (2) RTD was measured for cervical extension and flexion. Adherence to training was self-reported and categorized as regular if performed at least once a week.Results: MVC for cervical extension was significantly increased at follow-up in ETG (37.5 ± 11.2 Nm at baseline, change: 2.1 ± 8.3 Nm) compared to REF (38.1 ± 10.7 Nm at baseline, change: −2.4 ± 6.8 Nm) according to intension-to-treat analysis (p = 0.018). Likewise, RTD was significantly increased in ETG for cervical extension (149.6 ± 63.3 Nm/s at baseline, change: 14.7 ± 49.0 Nm/s) compared to REF (165.4 ± 84.7 Nm/s at baseline, change: −16.9±70.9 Nm/s) (p = 0.034). The cervical extension/flexion MVC-ratio was significantly different at follow-up (p = 0.039) between ETG (1.5 ± 0.5 at baseline, change: −0.0 ± 0.3) compared to REF (1.5 ± 0.5 at baseline, change: −0.2 ± 0.4). Per-protocol analysis of MVC, including only participants in ETG with regular training adherence (n = 10), showed a significant increase for cervical extension (33.2 ± 7.3 Nm at baseline, change: 6.0 ± 5.4 Nm) and shoulder elevation right side (143.0 ± 25.8 Nm at baseline, change: 15.8 ± 18.1 Nm).Conclusion: Physical exercise training significantly improved MVC and RTD in the upper neck extensors. Only approximately 1/3 of participants in ETG adhered to training regularly, which likely attenuated the effectiveness of the training intervention on neck and shoulder muscle function. Future studies should focus on the practical implementation of self-administered exercise training to improve adherence.

저고도 운용 항공기를 위한 기상정보의 필요성에 관한 연구

According to the Ministry of Land, Infrastructure and Transport press release ('18.12.21.) The amendment of the Aviation Business Act will reduce the capital requirements for aviation leisure operators and make it easier to enter aviation leisure businesses by improving regulations on small air transportation business. In addition, as the scale of the UAV(Unmanned Aerial Vehicle) sector is expected to increase globally, the dramatic increase in low altitude operating aircraft, including this, must be taken into account. The low altitude aircraft category is divided into small airplanes, helicopters, light aircrafts and ultra-light aircrafts, and instructors include school instructor pilots and student pilots, military and national helicopter pilots, and aviation leisure operators. In case of low altitude aircraft, there are cases of canceling operations due to low visibility and low clouds, and aircraft accidents due to excessive operation and sudden weather phenomenon. Therefore, in order to prevent low-altitude aircraft accidents, a safe flight plan based on weather conditions and weather forecasts and more accurate and local weather forecasts and weather forecast data are needed to prepare for the rapidly changing weather conditions.

Better brain connectivity is associated with higher total fat mass and lower visceral adipose tissue in military pilots

A lack of exercise leads to being overweight or obese affecting regional brain structure and functional connectivity associated with impaired cognitive function and dementia. In recent decades, several studies of healthy individuals suggest that adiposity may also produce negative independent effects on the brain. We aimed to investigate the relationship between body composition – total fat mass (TFM) and visceral adipose tissue (VAT) – with white matter (WM) integrity using a whole-brain approach in military pilots. Twenty-three military helicopter pilots (Mage = 36.79; SD = 8.00; MBMI = 25.48; SD = 2.49) took part in the study. Brain volumes were studied using diffusion tensor imaging technique by means of a 3T Magnetom Tim Trio. Measurements of body mass index (BMI), TFM and VAT were obtained using Dual-energy X-ray Absorptiometry (DXA). The results showed that, on one hand, higher TFM was associated with higher white matter fractional anisotropy (FA) and, on the other hand, higher VAT was associated with lower FA. Data showed that TFM and VAT are the critical factors underlying WM integrity in combat helicopter pilots. The authors suggest that fat presence enhance brain connectivity while there is no excess, specifically in VAT.

Performance and health effects of mild hypoxic hypoxia in simulated 6-hour exposures between 2,438 and 3,048 metres

Introduction: The Royal Canadian Air Force (RCAF) imposes a daily 4-hour (h)limit for operating unpressurized aircrafts, including helicopters, between 2,438 and 3,048 m (8,000 [8K] and 10,000 [10K] ft) if supplemental oxygen (O2) is unavailable. This regulation may negatively impact RCAF operations because weight and space restrictions limit sufficient O2 to achieve mission success. The effects of exposure durations beyond the 4-h limit are currently unknown, but extensions have the potential to improve operational effectiveness. This study examined the effects of hypoxic exposures on symptoms, mood and performance as a function of altitude and exposure duration. Methods: Seventeen military helicopter pilots were randomly exposed to two 6-h altitude levels (8K and 9.9K) on 2 separate days in a hypobaric chamber. Daily, participants periodically performed a simulated rotary wing flight task, and completed a cognitive test battery. Cerebral regional and finger pulse oxyheamoglobin saturation levels and heart rate were continuously monitored. Participants indicated their subjective hypoxia signs and symptoms, mood and fatigue. Results: Exposure to altitude significantly decreased cerebral and pulse O2 saturations, but values remained steady during the 6-h exposure. No negative decrements were observed on cognition or simulation performance. Self-reported symptoms of fatigue and headache were reported at altitude with a slight increase with time. Discussion: No clear evidence of significant deficits on performance was observed in participants when exposed to mild levels of hypoxia for up to 6 h without supplemental O2.

Acute Mild Hypoxic Hypoxia Effects on Cognitive and Simulated Aircraft Pilot Performance.

The effects of acute mild hypoxic hypoxia (HH) and physical activity on physiological measures, signs and symptoms, mood, fatigue, cognition, and performance on a simulated flight task were investigated between 8000 (8K; 2438 m) and 14,000 ft (14K; 4267 m). In a hypobaric chamber, 16 military helicopter pilots were randomly exposed to 4 altitudes and 3 physical exertion levels. After each exercise period, participants identified targets on a designated flight path on a desktop simulator and completed a cognitive test battery. Cerebral regional and finger pulse oxyhemoglobin saturation levels (rSO2 and Spo2), heart and respiration rates were continuously monitored. Participants indicated their symptoms, mood and fatigue. rSO2 and Spo2 were affected by the increase of altitude and exercise level. Target identification accuracy and latency within the simulated flight task showed decrements at 8K, 10K (3048 m), 12K (3658 m), and 14K. Cognitive performance was degraded at 14K. More than 60% of the participants at 8K and 10K and more than 80% at 12K and 14K reported symptoms. Altitude increased symptoms, negative mood, general fatigue, and physical fatigue. Our findings indicate a significant influence of mild HH on a number of outcome measures at altitudes above 10K, where operational restrictions are well established. In contrast, there was no clear influence of HH on performance at lower altitudes (i.e., 8K and 10K). The occurrence of HH symptoms and the decrements in target identification latency and accuracy at 8K and 10K may negatively impact flight performance and require further study.Bouak F, Vartanian O, Hofer K, Cheung B. Acute mild hypoxic hypoxia effects on cognitive and simulated aircraft pilot performance. Aerosp Med Hum Perform. 2018; 89(6):526-535.

Lumbar Disc Herniation in Military Helicopter Pilots vs. Matched Controls.

Lumbar disc herniation (LDH) is a common injury among active duty service members resulting in missed duty hours and limited duty status. Little is known about the current burden of disease and risk factors for LDH among military rotary wing aviators. A query was made using the Defense Medical Epidemiology Database (DMED), including patient encounters for the U.S. Military from 2006-2015 using the ICD-9 code for LDH. Incidence rates were calculated for patients with the occupation of helicopter pilot and stratified by age, gender, and branch of service, then compared to matched controls using a Poisson regression analysis. Then, data from a 17-yr period were examined for long term trends. We identified 1218 cases of LDH among 141,383 person-years among helicopter pilots, yielding a 1.22-fold higher incidence rate compared to controls. Significant risk factors identified after Poisson regression analysis were age greater than 30 yr old and Army service branch affiliation. Male gender was not found to be a significant risk factor. Long term data revealed a 2.6-fold increased incidence of LDH among helicopter pilots since 1997. We identified significant increased risk of LDH in rotary wing pilots as compared to their nonpilot peers. Among rotary wing pilots, the incidence of this condition has increased, with both increasing pilot age and Army branch affiliation identified as risk factors. This information will allow targeted prevention strategies and further investigation to potential aircraft-specific causes of increased risk in Army pilots.Knox JB, Deal JB Jr, Knox JA. Lumbar disc herniation in military helicopter pilots vs. matched controls. Aerosp Med Hum Perform. 2018; 89(5):442-445.

A maximal incremental effort alters tear osmolarity depending on the fitness level in military helicopter pilots

PurposeFitness level modulates the physiological responses to exercise for a variety of indices. While intense bouts of exercise have been demonstrated to increase tear osmolarity (Tosm), it is not known if fitness level can affect the Tosm response to acute exercise. This study aims to compare the effect of a maximal incremental test on Tosm between trained and untrained military helicopter pilots. MethodsNineteen military helicopter pilots (ten trained and nine untrained) performed a maximal incremental test on a treadmill. A tear sample was collected before and after physical effort to determine the exercise-induced changes on Tosm. ResultsThe Bayesian statistical analysis demonstrated that Tosm significantly increased from 303.72 ± 6.76 to 310.56 ± 8.80 mmol/L after performance of a maximal incremental test. However, while the untrained group showed an acute Tosm rise (12.33 mmol/L of increment), the trained group experienced a stable Tosm physical effort (1.45 mmol/L). There was a significant positive linear association between fat indices and Tosm changes (correlation coefficients [r] range: 0.77–0.89), whereas the Tosm changes displayed a negative relationship with the cardiorespiratory capacity (VO2 max; r = −0.75) and performance parameters (r = −0.75 for velocity, and r = −0.67 for time to exhaustion). ConclusionsThe findings from this study provide evidence that fitness level is a major determinant of Tosm response to maximal incremental physical effort, showing a fairly linear association with several indices related to fitness level. High fitness level seems to be beneficial to avoid Tosm changes as consequence of intense exercise.

Self-administered physical exercise training as treatment of neck and shoulder pain among military helicopter pilots and crew: a randomized controlled trial

BackgroundNeck pain is frequent among military helicopter pilots and crew-members, and pain may influence individual health and work performance. The aim of this study was to examine if an exercise intervention could reduce neck pain among helicopter pilots and crew-members.MethodsThirty-one pilots and thirty-eight crew-members were randomized to either an exercise-training-group (n = 35) or a reference-group (n = 34). The exercise-training-group received 20-weeks of specific neck/shoulder training. The reference-group received no training. Primary outcome: Intensity of neck pain previous 3-months (scale 0-10). Secondary outcomes: additional neck/shoulder pain intensity variables and pressure-pain-threshold in the trapezius muscle (TRA) and upper-neck-extensor muscles (UNE). Regular training adherence was defined as ≥1 training session a week. Statistical analyses performed were intention-to-treat and per-protocol. Students t-test was performed (p < 0.05).ResultsIntensity of neck pain previous 3-months at baseline was: 2.2 ± 1.8 and previous 7-days: 1.0 ± 1.5, and pressure-pain-threshold in TRA and UNE (right/left) was in kPa: 424 ± 187 / 434 ± 188 and 345 ± 157 / 371 ± 170 in the exercise-training-group, and 416 ± 177 / 405 ± 163 and 334 ± 147 / 335 ± 163 in the reference-group, with no differences between groups. Intention-to-treat-analysis revealed no significant between-group-differences in neck pain intensity and pressure-pain-threshold. Between-group-differences, including participants who trained regularly (n = 10) were also non-significant. Within-group-changes were significant among participants with regular training adherence in the exercise-training-group regarding intensity of neck pain previous 3-months (from 2.2 ± 0.6 to 1.3 ± 1.3, p = 0.019). Likewise, within the whole exercise-training-group, neck pain previous 7-days decreased (from 1.0 ± 1.4 to 0.6 ± 1.1, p = 0.024). Additional within-group-changes regarding pressure-pain-threshold in kPa were for the reference-group a reduction in TRA and UNE (right/left) to: 342 ± 143 / 332 ± 154 and 295 ± 116 / 292 ± 121 implying increased pain sensitivity, while for the exercise-training-group only a reduction in left TRA was seen: 311 ± 113.ConclusionsThe exercise intervention did not reduce neck pain among helicopter pilots and crew-members as no significant between-group-differences were found. However, some trends were demonstrated as some neck pain intensity and sensitivity improved more within the exercise-training-group but not within the reference-group. The lack of effect may be due to low adherence since only ~ 1/3 of subjects in the exercise-training-group engaged in regular training which may be due to the self-administration of the training.Trial registrationsEthical committee of Southern Denmark (S-20120121) 29 August, 2012. Clinical Trail Registration (NCT01926262) 16 August, 2013.

Reported Back Pain in Army Aircrew in Relation to Airframe, Gender, Age, and Experience.

Back pain has remained an issue of significance among aircraft crewmembers for decades, occurring in the majority of military helicopter pilots with potential deleterious effects on performance, safety, and operational readiness. This exploratory, correlational survey study was designed to evaluate the presence of patterns and relationships that may require further examination to understand causal factors. The study population consisted of U.S. Army aviation crewmembers. Subjects (467) completed an anonymous survey, including questions regarding demographics, airframes, experience, pain history and severity, ergonomics, mitigation strategies, and duty limitations. Overall, 84.6% of participants reported back pain at some time during their flying career, with 77.8% reporting back pain in the last calendar year. Age was found to significantly correlate with earlier time to pain during flight, higher pain rating after flight, and occurrence of grounding. A stepwise linear regression model was used to explore the relationships between age, flight hours, and years of aviation experience, demonstrating age to be the significant variable accounting for the observed variance. Aircrew reported wear of combat-related survival equipment and poor lumbar support to be the most notable contributors. Back pain rates were consistent with previous studies. The relationship of age to back pain in this study may highlight unique pathophysiological pathways that should be further investigated within an occupational context to better understand the etiologic role. Enhanced seated lumbar support and combat-related survival equipment remain relatively low-cost/high-yield topics worthy of further investigation for exploiting efficient means to improve health, safety, and operational performance.Kelley AM, MacDonnell J, Grigley D, Campbell J, Gaydos SJ. Reported back pain in army aircrew in relation to airframe, gender, age, and experience. Aerosp Med Hum Perform. 2017; 88(2):96-103.

Fatigue in the military: towards a fatigue detection test based on the saccadic velocity

Fatigue is a major contributing factor to operational errors. Therefore, the validation of objective and sensitive indices to detect fatigue is critical to prevent accidents and catastrophes. Whereas tests based on saccadic velocity (SV) have become popular, their sensitivity in the military is not yet clear, since most research has been conducted in laboratory settings using not fully validated instruments. Field studies remain scarce, especially in extreme conditions such as real flights. Here, we investigated the effects of real, long flights on SV. We assessed five newly commissioned military helicopter pilots during their aviation training. Pilots flew Sikorsky S-76C helicopters, under instrumental flight rules, for more than 2 h (ca. 150 min). Eye movements were recorded before and after the flight with an eye tracker using a standard guided-saccade task. We also collected subjective ratings of fatigue. SV significantly decreased from the Pre-Flight to the Post-Flight session in all pilots by around 3% (range: 1–4%). Subjective ratings showed the same tendency. We provide conclusive evidence about the high sensitivity of fatigue tests based on SV in real flight conditions, even in small samples. This result might offer military medical departments a valid and useful biomarker of warfighter physiological state.

The Effect of Target Position on the Accuracy of Cervical-Spine-Rotation Active Joint-Position Sense

Context:The cervical spine can be divided into upper and lower units, each making a different contribution to the magnitude of rotation and proprioception. However, few studies have examined the effect of the cervical-rotation positions on proprioception.Objective:To compare cervical-spine rotation active joint-position sense (AJPS) near midrange of motion (mid-ROM; 30°) and near end-ROM (60°).Design:Cross-sectional study.Setting:Human performance research laboratory.Participants:53 military helicopter pilots (age 28.4 ± 6.2 y, height 175.3 ± 9.3 cm, weight 80.1 ± 11.8 kg).Main Outcome Measures:A motion-analysis system was used to record cervical-rotation kinematics. Subjects sat in a chair wearing a headband and blindfold. First, they actively rotated the head right or left to a target position (30°/60°), with real-time verbal cues provided by the tester. Subjects held the target position for 5 s and then returned to the start position. After this, they replicated the target position as closely as possible. Five trials were performed in both directions to both target positions (R30/R60/L30/L60). Order of direction/position was randomized. The difference between target and replicated positions was calculated and defined as absolute error (AE), and the mean of 5 trials was used for analyses. Wilcoxon signed-ranks tests were used to compare AJPS at the different target positions (P &lt; .0125 with Bonferroni adjustments).Results:End-ROM AEs were significantly more accurate than mid-ROM AEs (P = .001).Conclusion:Cervical-spine-rotation AJPS is more accurate near end-ROM than mid-ROM. Both target positions should be used to examine cervical-spine-rotation AJPS of both the upper and lower units.

Lumbar spine and hip flexibility and trunk strength in helicopter pilots with and without low back pain history.

Low back pain (LBP) is one of the most common musculoskeletal issues facing military helicopter pilots. It is clinically important to identify differences in musculoskeletal characteristics between pilots with and without a LBP history for formulating effective interventions. To compare lumbar spine and hip flexibility and trunk strength in pilots with and without a LBP history. A total of 30 pilots with a LBP history were matched with pilots without a LBP history. An isokinetic dynamometer and a digital inclinometer were used to evaluate trunk and hip strength and a range-of-motion (ROM), respectively. All tests were performed bilaterally, if applicable, and agonist/antagonist ratios and side-to-side (low/high) symmetries were calculated. Paired t-tests or Wilcoxon tests were used to assess group differences (p < 0.050). The LBP group demonstrated significantly lower trunk extension strength and trunk extension/flexion strength ratio (p < 0.008). The LBP group demonstrated significantly less lateral flexion ROM as well as greater lateral flexion and rotation side-to-side asymmetry (p < 0.009). The LBP group demonstrated significantly greater total hip rotation side-to-side asymmetry (p = 0.037). Given the results, specific exercises that are targeted to improve trunk strength, ROM, and side-to-side symmetries could be developed to reduce LBP in helicopter pilots.