Acceleration effects on neck muscle strength: pilots vs. non-pilots

BACKGROUND: Conditioning of neck muscles, if any, due to repeated exposures to +Gz forces has received little research attention. OBJECTIVE: This study was conducted to evaluate and compare the neck muscle strength of test volunteers representative of the general populations of fighter aircraft pilots and non-pilots. METHODS: The tests were performed using a special attachment device on a computerized dynamometer. Ten pilots and ten non-pilots volunteered as test subjects. Each individual's maximal isometric neck muscle strength was evaluated in the extension, flexion, and left and right lateral bending directions in a single day. Peak values from the measurements were used for data analysis. Overall neck strength was calculated as the mean values for the four directions in each group. RESULTS: The overall muscular strength of the necks of pilots did not differ significantly from that of non-pilots, nor did exposure to +Gz forces lead to specific changes in isometric muscle strength across any of the four principal directions. Neck muscle strength in the four measured directions pooled across the two subgroups were statistically significant. The widespread practice of adopting protective head-positioning strategies to minimize neck strains, coupled with results from this research study, suggest that the neck muscles are subjected to reduced in-flight strengthening workouts during exposures to +Gz forces. CONCLUSIONS: To maximize in-flight performance and minimize +Gz-induced neck injuries, fighter pilots should be encouraged to perform on-land neck muscle strengthening exercise and in-flight head-positioning techniques. More research is needed to fine-tune this countermeasure strategy against cervical spine injury.     

Neck strength and EMG activity in fighter pilots with episodic neck pain

INTRODUCTION: Neck pain is common in fighter pilots due to repeated exposure to high +Gz loads, but studies comparing neck function in symptomatic and healthy fighter pilots are lacking. This study compared neck strength and EMG activity during maximal isometric contractions in a sitting position in the sagittal and coronal planes in neck pain (SP), asymptomatic fighter pilots (AP), and healthy, male, non-pilot subjects (NPS). METHODS: There were 9 SP, 10 AP, and 8 NPS, all males, who performed maximal isometric neck contractions on a specific dynamometer. Surface EMG activity was recorded bilaterally over the sternocleidomastoid and paraspinal muscles. EMG amplitude during side bending was normalized to that measured in the sagittal plane. RESULTS: SP exhibited lower side-bending strength than AP (17-19%, P < 0.05). In addition, SP and NPS exhibited lower left side-bending-to-extension torque ratios (20% and 14%, respectively, P < 0.05) than AP. Similar activation level of neck flexors and extensors during side bending was found in SP and AP, whereas EMG activity of the extensors was higher than the flexors in NPS (+48%, P < 0.05). In addition, antagonistic EMG activity was higher in AP compared to NPS (26% vs. 41%, respectively, P < 0.05). CONCLUSION: Our results suggest altered muscle function in SP compared with AP in the coronal but not in the sagittal plane. Further, AP appeared to be more efficient in the coronal plane with reference to neck extension than NPS, suggesting that some adaptations occurred due to flight exposure. These findings may have clinical implications for the management and the follow-up of neck pain in fighter pilots.     

Neck muscle strength and endurance in fighter pilots: effects of a supervised training program

INTRODUCTION: Cervical discomfort is common among pilots of high performance aircraft. An exercise program was introduced to increase the strength and endurance of the neck muscles. The purpose of this study was to analyze whether coaching or reinforcement strategies by a physical therapist was associated with improvement in neck muscle strength, endurance, and neck complaints in two cohorts of fighter pilots performing regular neck muscle exercises. METHODS: A reinforced group (RG) of 20 pilots (24-40 yr) at an Air Force base received weekly encouragement to perform their standardized exercise program three times per week. A non-reinforced reference group (NRG) of 20 pilots (23-37 yr) from another Air Force base carried out the same program without any supervision. Both groups performed the training program for 6-8 mo. Before and after the training period, isometric measurements of the neck flexors and neck extensors were performed in both groups. RESULTS: After the completion of the 6-8 mo training period, the RG pilots significantly increased their neck muscle strength (flexors: M = 3.9 nm, p = 0.000 and extensors: M = 5.0 nm, p = 0.001) as well as endurance in their neck extensors (M = 53 s, p = 0.000). The NRG pilots significantly decreased both strength (M = 11.5 nm, p = 0.0001) and endurance (M = 33 s, p = 0.003) of their neck extensors. Furthermore, the NRG pilots did not show any significant change of their neck flexor strength. No significant changes in the frequency of neck complaints were reported in either group throughout the entire study period. CONCLUSION: The reinforced training program increased the strength and endurance of the appropriate muscle groups. In order to draw any further conclusions concerning reducing neck complaints, a longer observation period with a larger group of pilots might be needed. However, it is likely that there is an individual correlation between strength and endurance of the neck muscles and neck pain, which means that any rehabilitation program should be tailored for each individual.     

Back muscle EMG of helicopter pilots in flight: effects of fatigue, vibration, and posture

INTRODUCTION: The high prevalence of low back pain in helicopter pilots has been attributed to back muscle fatigue due to a pilot's required posture and/or aircraft vibration. This study investigated the effect of posture and vibration on the surface electromyogram (EMG) of right and left erector spinae (ES) muscles of pilots and evaluated ES fatigue during flight. METHODS: There were 12 male pilots who were monitored during helicopter flights lasting an average of 2 h. Prior to the flight, a maximal voluntary contraction (MVC) of ES was performed and the EMG was recorded. Vibration was measured at the pilot's seat through a triaxial accelerometer. The effect of posture on EMG was tested by comparing four characteristics of left and right EMG expressed as % MVC. Effect of Z vibration on EMG was investigated by coherence function and through correlation between coherently averaged EMG and Z for the frequencies of the main rotor of the helicopter (1R) and its first harmonic (2R). Fatigue was investigated through median frequencies (MF) of the EMG power spectra. RESULTS: No effect of posture on EMG was found for any parameter (p > 0.05). Data from one pilot suggested an effect of 1R on EMG, but statistical tests revealed this not to be significant (p > 0.05) for any pilot. No fatigue was evidenced by linear regression of MF. CONCLUSION: While the scientific literature contains the hypothesis that low back pain in helicopter pilots is mainly due to muscle fatigue caused by posture and/or vibration, the present study did not lend support to this hypothesis.     

Neck exercises compared to muscle activation during aerial combat maneuvers

INTRODUCTION: Performing specific neck strengthening exercises has been proposed to decrease the incidence of neck injury and pain in high performance combat pilots. However, there is little known about these exercises in comparison to the demands on the neck musculature in flight. METHODS: Eight male non-pilots performed specific neck exercises using two different modalities (elastic band and resistance machine) at six different intensities in flexion, extension, and lateral bending. Six Royal Australian Air Force Hawk pilots flew a sortie that included combinations of three +Gz levels and four head positions. Surface electromyography (EMG) from selected neck and shoulder muscles was recorded in both activities. RESULTS: Muscle activation levels recorded during the three elastic band exercises were similar to in-flight EMG collected at +1 Gz (15% MVIC). EMG levels elicited during the 50% resistance machine exercises were between the +3 Gz (9-40% MVIC) and +5 Gz (16-53% MVIC) ranges of muscle activations in most muscles. EMG recorded during 70% and 90% resistance machine exercises were generally higher than in-flight EMG at +5 Gz. DISCUSSION: Elastic band exercises could possibly be useful to pilots who fly low +Gz missions while 50% resistance machine mimicked neck loads experienced by combat pilots flying high +Gz ACM. The 70% and 90% resistance machine intensities are known to optimize maximal strength but should be administered with care because of the unknown spinal loads and diminished muscle force generating capacity after exercise.     

Thoracolumbar pain among fighter pilots.

High +Gz forces place high stress on the spinal column, and fighter pilots flying high-performance fighter aircraft frequently] report work-related thoracic and lumbar spine pain. The aim of this study was to determine whether +Gz exposure causes work-related thoracolumbar spine pain among fighter pilots. A questionnaire was used to establish the occurrence of thoracic and lumbar spine pain during the preceding 12 months and during duties over the whole working career among 320 fighter pilots and 283 nonflying controls matched for age and sex. Thirty-two percent of the pilots and 19% of the controls had experienced pain in the thoracic spine during the preceding 12 months (odds ratio [OR] = 2.3; 95% confidence interval [CI] = 1.5-3.5; p = 0.002 for the pilots). Among the pilots, the OR increased up to 6.1 (95% CI = 1.6-23.1; p = 0.0007) with the number of +Gz flight hours. There was no difference between the groups with regard to lumbar pain during the preceding 12 months, but over their whole working careers fighter pilots (58%) had experienced lumbar pain during their duties more often than controls (48%) (OR = 1.8; 95% CI = 1.3-2.6; p = 0.002). The greater the number of +Gz flight hours, the greater the occurrence of lumbar spine pain when on duty (OR = 26.9; 95% CI = 6.2-116; p = 0.0001 for the most experienced fighter pilots). The same was not true with regard to the number of +Gz flight hours and lumbar pain during the preceding 12 months. Age had no effect on pain in the thoracic or lumbar spine. Fighter pilots flying high-performance aircraft have more work-related thoracic and lumbar spine pain than controls of the same age and sex. The difference is explained by the pilots' exposure to +Gz forces.     

The effects of 12 weeks of functional strength training on muscle strength,volume and activity upon exposure to elevated Gz forces in high-performance aircraft personnel

Background:Technological advancements in modern military and acrobatic jet planes have resulted in extraordinary psychophysiological loads being exerted upon flying personnel,including inducing neck and back pain.The purpose of this study was to examine the effects of 12 weeks of functional strength training on 1) the volume and strength of the neck and shoulder muscles and 2) muscular activity upon exposure to helmets of different masses and elevated Gz forces in a long-arm centrifuge in high-performance aircraft personnel.Methods:Eighteen participants underwent 12 weeks of functional strength training (n=12) or the control protocol(n=6) without additional strength training.Pre-and post-intervention tests included evaluations of isometric strength of the head extensor muscles,flexion,and lateral flexion and rotation,as well as magnetic resonance imaging (MRI)to measure the volume of the m.stemocleidomastoideus,m.trapezius,and deep neck muscles.Furthermore,during a long-arm centrifuge (+1.4 and +3Gz) protocol,the muscular activity levels of the m.sternocleidomastoideus,m.trapezius and m.erector spinae muscles were assessed without a flight helmet,with a helmet,and with a helmet and night vision goggles.Each participant's perception of muscular strain was noted immediately after the long-arm centrifuge protocol.Results:The maximal isometric strength in all exercises and muscle volumes increased in the training group but not the control group (P＜0.05).Relative muscle activity (％MVC) with a helmet decreased after the intervention in the training but not the control group (P=0.01).Relative muscle activity while wearing a helmet and night vision goggles was higher after intervention in the control group than in the training group (P＜0.01).The perceived muscular strain of the neck muscles induced by the long-arm centrifuge did not differ between the groups.Conclusions:Twelve weeks of functional strength training improves the maximal isometric strength and volume of neck and shoulder muscles and leads to lower relative muscle activation upon exposure to elevated Gz forces in a long-arm centrifuge.     

Low back pain in pilots

A questionnaire on low back pain (LBP) was administered to 373 fighter pilots, 165 transport pilots, and 264 helicopter pilots. Helicopter pilots had more pain during flight than did fighter or transport pilots (34.5%, 12.9%, and 5.1%, respectively). A history of LBP temporally unassociated with flight was found in 26.5% of helicopter pilots, 31.5% of transport pilots and 25.2% of fighter pilots. We conclude that, despite the pain experienced by helicopter pilots in flight, they are not at increased risk for LBP unassociated with flight.     

Head positioning and neck muscle activation during air combat

INTRODUCTION: Specific mechanisms leading to acute neck injury in flight as a result of +Gz exposure remain unclear. In this study, head positions adopted by aircrew in air combat have been quantified, and the associated levels of cervical muscle activation have been determined. METHOD: Six fast jet aircrew subjects were instrumented with surface electromyography (EMG) electrodes, and activation potentials from neck erector spinae (ES) and sternocleidomastoid (SC) muscles were logged on a data recorder. EMG signal was normalized to preflight maximum voluntary contraction (MVC). All subjects flew a one-on-one air combat sortie in a Hawk T1 aircraft comprising at least four air combat engagements. In-cockpit video and +Gz acceleration were recorded. Time-synchronized analysis of video, EMG, and acceleration were conducted for head position and normalized muscle activation (%MVC). RESULTS: During air combat, the head was away from neutral for 68% of the time, predominantly in extension, or rotation plus extension. During neck extension under G, 40-80% MVC occurred in the ES: this was reduced by half when the canopy was used as a support. Similar activation occurred in the SC in neck extension plus rotation. The ES was activated at over 40% MVC for 25% of the engagement duration. Postsortie, 35% reduction in neck muscle strength occurred. CONCLUSIONS: Extreme neck extension +/- rotation is very common in air combat and is associated with high levels of muscle activation and fatigue. This information can be used to help devise targeted neck conditioning and positioning strategies in order to reduce injury risk.     

Cervical and lumbar MRI findings in aviators as a function of aircraft type

BACKGROUND & AIMS: Neck pain and lower back pain (LBP) are frequently reported by military helicopter pilots (HP) and fighter pilots. A small number of studies have used imaging methods to evaluate spinal cervical degenerative findings in pilots exposed to high +Gz, with results indicating an increase in cervical disk protrusions in this population. We evaluated the cervical and lumbar spine with magnetic resonance imaging (MRI) to assess the prevalence of degenerative changes in three subpopulations of pilots. METHODS: Fighter pilots (FP), transport pilots (TP), and HP (10 pilots in each group) underwent cervical and lumbar MRI. Degenerative pathologic changes (disk herniation, cord compression, foraminal stenosis, and the presence of osteophytes) were evaluated in each group by two independent experienced radiologists. RESULTS: Cervical spine degenerative changes seemed to be associated with older age rather then aircraft type, affecting the older group of TP (8/10 pilots) more than the younger FP group who were exposed to high +Gz (3/10 pilots). In contrast, for lumbar spine degenerative changes, we found an uncommon pattern of lumbar spine degeneration in HP, affecting the upper part of the lumbar spine (10/13 disks found at L1-L4). CONCLUSIONS: The results of this study suggest that HP may have detectable degenerative lumbar findings. More research is needed to validate these findings as well as to explore the possible pathophysiological link between occupational exposures and the specific involvement of the upper lumbar spine.     

战斗机高+Gz环境导致飞行员颈部损伤的原因及预防措施

目的 综述战斗机高+Gz环境导致飞行员颈部损伤的致伤原因、发生机制及预防措施,探讨采取综合性措施提升预防效果的发展前景.资料来源与选择国内外相关领域的研究论文与综述.资料引用国内外公开发表的论文和综述50篇.资料综合高性能战斗机的高+Gz值、高+Gz增长率特性给飞行员颈部健康造成极大的危害.近20多年来,众多学者针对高+Gz环境导致飞行员颈部损伤的机制和致伤原因进行了研究.在致伤阈值、头戴装备负荷、被动带飞、不良飞行姿态和反复暴露于高+Gz环境等致伤因素方面取得了较为一致的结果,提出的预防措施主要有加强颈部肌肉力量训练,研制防护装备及改善装备人机适配性,建立常规化的健康检查、康复训练、功能评价机制等.结论 战斗机飞行员在飞行职业生涯中不可避免地受到高+Gz环境的威胁,在当前单一预防措施效果不显著的情况下,积极采取综合性预防措施,并加强其预防效果的研究,对增强飞行员的飞行适应能力,提高飞行员健康水平将有极大的推动作用,并为高+Gz环境导致腰部损伤的预防工作提供借鉴经验. Abstract： Objective To review the reasons, mechanism of fighter aircraft high +Gz induced pilot's neck injuries and prevention methods, and to expect the integrative methods for enhancing prevention effects.Literature resource and selection Professional references which were published at home and abroad were cited.Literature quotation Fifty published papers and reviews were referred.Literature synthesis The characters of modern high-performance fighter aircraft which was described as high +Gz and the rapid onset rate acceleration induced serious harm to pilot's neck.Since more than 20 years, many researches on mechanism and the reasons of inducing neck injuries had conducted by scholars.They indicated the consensus in the factors of inducing neck injuries, including +Gz threshold, the load on pilot's head, passive effect on back seat, unsuitable head posture in flight and frequent exposure in high +Gz.The preventions were primarily focused on leaning upon cervical spine function evaluation and neck muscle strength training, developing protective equipment and improving man-machine adaptability of equipment.Conclusions In fighter pilot's career, it is unavoidable that he will be threatened by high +Gz environment.At present, it is important to adopt integrative preventions and emphasize effective research for increasing pilot's capability for adapting high + Gz environment and protecting himself.Also such experience will be useful in preventing pilot's waist injuries induced by high +Gz.     

The effect of helmet mass and aircraft acceleration on cervical spine loads during typical fast jet aircraft pilot head motions

ObjectivesGravitational Force (Gz), head motion, and helmet mass are associated with neck pain in high performance aircraft pilots. Few studies have quantified neck kinetics (intersegmental neck moments) during aerial combat manoeuvres.DesignCross-sectional.MethodsWe quantified net joint moments between the skull and C1, and C6–7 during typical flight related headchecks using the Musculoskeletal Model for the Analysis of Spinal Injuries (MASI). We measured the influence of pilot-specific helmets and Gz on joint moments. Nineteen fighter pilots performed four head checks (check6 left, check6 right, extension hold and extension scan) under two helmet conditions. Motion data were transferred to OpenSim where joint moments were calculated at 1G to 9G. Net joint moments were compared across helmet conditions, Gz and headchecks.ResultsThe Joint Helmet Mounted Cueing System (JHMCS) resulted in higher moments at each segment- by a factor of 1.25 per unit of Gz, at C1, and by a factor of 1.08 per unit of Gz for C7. ExtensionScan and Check6Left were associated with the highest peak (96.13 Nm and 92.56 Nm). ExtensionScan and ExtensionHold accrued the highest mean cumulative loads at C7 at 9Gz (607.35 Nm.sec/motion, 362.99 Nm.sec/motion respectively). Asymmetries were observed between the Left and Right Check6 motions. High variability was evident between and within pilots.ConclusionsThe MASI model has been successfully applied to quantify intersegmental neck joint moments for typical headchecks that are performed during combat flight manoeuvres. In future, data derived from this model may inform conditioning, rehabilitative and preventative interventions to reduce neck pain in fast jet pilots.     

高性能飞机飞行员非冲击性颈部损伤的研究进展

概述了高性能飞机飞行员受高＋Gz所致非冲击性颈部损伤的研究进展，对预部损伤机理及类型进行了分析。指出了“检查6点钟”位置最容易引起颈部损伤。颈部损伤的症状可影响飞行员的飞行能力及日常生活，但经治疗后多可恢复飞行，只有少数严重损伤者需转飞其他机种。新型头颈支持系统、轻型头盔、以及颈肌强化锻炼有助于颈部损伤的预防。     

飞行员年度体检疾病谱比较分析

目的 比较2012年陆军航空兵直升机飞行员和空军歼击机飞行员疾病谱,分析其异同,为航卫保障提供依据. 方法 随机抽取参加2012年大体检的陆军航空兵直升机飞行员652人和空军歼击机飞行员830人,分别计算其疾病谱前10位疾病的患病率.分别按年龄分为20～29岁、30～39岁、40岁以上组,计算两个人群各年龄组疾病谱前10位疾病的患病率;计算并比较两个人群各系统疾病的患病人数及其构成比. 结果 ①陆军航空兵飞行员和空军飞行员前4位疾病均为高脂血症、脂肪肝、高尿酸血症、胆囊息肉,患病率分别是15.64％、14.57％、6.44％、5.37％和24.22％、19.85％、14.08％、9.17％.②高脂血症、脂肪肝在陆军航空兵飞行员和空军飞行员各年龄段中均排在前两位.③消化系统疾病与内分泌、营养和代谢疾病在2012年陆军航空兵飞行员和空军飞行员疾病谱中均居前两位,患病率分别是45.66％、26.91％和39.69％、28.37％. 结论 陆军航空兵飞行员主要疾病与空军飞行员基本相似;消化系统疾病及内分泌、营养和代谢疾病是本组飞行员疾病的主要类型;高脂血症、脂肪肝是其主要病种.内分泌、营养和代谢疾病成为影响陆军航空兵飞行员身体健康的重要疾病.     

Effect of Gz forces and head movements on cervical erector spinae muscle strain.

A portable surface-integrated EMG (IEMG) device was used to investigate the strain caused by low and high Gz forces and head movements on the cervical erector spinae muscles during flight missions. The obtained IEMG activities were normalized by comparing them with activities representing maximal voluntary contraction (MVC) of the cervical erector spinae muscles in each subject. The muscular strain increased with increasing Gz forces and head movements. Under +7.0 Gz the mean muscular strain was 5.9-fold compared with +1.0 Gz and was 37.9% of the MVC. In some individuals, the muscular tolerance (100% of the MVC) was ipsilaterally reached already under +4.0 Gz with concomitant movements and twisted positions of the head. Pilots are susceptible to acute neck injury when the protection afforded by their neck muscles is insufficient.     

G-induced visual and cognitive disturbances in a survey of 65 operational fighter pilots

INTRODUCTION: Only one previous study has assessed almost loss of consciousness (A-LOC) in operational fighter pilots, reporting an incidence rate of 14%. Research also indicates that 8-13% of pilots have experienced G-induced loss of consciousness (G-LOC). A-LOC can be as insidious as G-LOC due to the associated altered state of awareness and relative incapacitation time, making it a significant risk factor in the high +Gz environment. Royal Australian Air Force (RAAF) pilots currently fly the F/A-18 and Hawk 127, producing +Gz accelerations up to +7.5 Gz, which places these pilots at risk of both A-LOC and G-LOC. METHODS: A survey was administered to 100 active RAAF fighter pilots requesting information on G-induced visual and cognitive disturbances, A-LOC symptoms, and G-LOC. Details regarding type of aircraft, flying maneuvers performed and mission outcome were also sought. RESULTS: There were 65 RAAF fighter pilots who completed the survey (age 20-53 yr, height 168-193 cm, weight 64-110 kg, jet hours 30-5700 h). Of these pilots, 98% indicated they had experienced at least one visual or cognitive disturbance in the high G environment: gray-out 98%; black-out 29%; and A-LOC symptoms 52%, including abnormal sensation in limbs, disorientation, and confusion. There were 9% who indicated they had experienced G-LOC (50% were the pilot flying the aircraft). DISCUSSION: These findings indicate that RAAF fighter pilots are experiencing a similar rate of visual disturbances and G-LOC when compared with other air forces. However, RAAF pilots reported a much higher incidence of A-LOC compared with the only other study of operational fighter pilots.     

Patterns of physical conditioning in Royal Australian Air Force F/A-18 pilots and the implications for +Gz tolerance.

BACKGROUND: The role of physical conditioning in tolerance to +Gz remains the subject of debate, particularly in relation to the relative merits of aerobic vs. anaerobic conditioning. The purpose of this study was to document the patterns of physical conditioning in Royal Australian Air Force (RAAF) fighter pilots and to relate these findings to the question of +Gz tolerance. METHODS: A questionnaire was used to determine the physical conditioning activities of RAAF F/A-18 pilots. Aerobic fitness levels (VO2max) were determined in a sample of eight pilots using a progressive cycle ergometer protocol. RESULTS: Of the 42 F/A-18 pilots who completed the questionnaire, 86% reported regular physical conditioning, mostly three times per week. Aerobic activities were the most common (83%), with running the most popular activity (55%). Anaerobic activities were reported by 26% of respondents. Most respondents reported doing more than one activity, with an average weekly training volume of 129+/-77 min. The ergometer test results revealed a mean VO2max of 50+/-6 ml O2 x kg x min(-1). CONCLUSION: The high rates of participation in regular physical activity suggest that physical fitness is perceived as important by the fighter pilot operating in the high +Gz environment. The fighter pilots in this study participated in aerobic activities at a much higher rate than anaerobic activities. The aerobic fitness levels measured suggest that the pilots have good but not exceptionally high levels of aerobic power that are unlikely to influence +Gz tolerance.     

Neck pain and related disability in helicopter pilots: A survey of prevalence and risk factors

INTRODUCTION: Today's demands on helicopter missions-often using helmet-mounted visual technology-place much physical stress on the cervical spine. The objective of the present analytical survey was to estimate the prevalence of, and associated risk factors for, helicopter pilots' neck pain and related disability. METHODS: There were 127 Swedish helicopter pilots consecutively enrolled for the study who completed a structured questionnaire during their regular medical health checkups. The questionnaire concerned flight-related and individual risk indicators, frequency of neck pain episodes, and disability. Multivariate regressions, with the potential to control for confounding factors, were used to estimate relative risks (RR). RESULTS: The 3-mo prevalence of neck pain was 57%, with 32% reporting frequent pain. A history of previous neck pain (RR = 1.8, 95% CI = 1.2-2.7) and recent shoulder pain (RR = 1.6, 95% CI = 1.1-2.4) were significant risk factors, while the use of night-vision goggles and muscle strength-training showed a non-significant associated trend, the latter toward a decreased risk. In neck pain cases, 58% and 55% reported that their pain interfered with their flying and leisure, respectively, and those with frequent pain risked pain interfering with flying duty (RR = 1.6, 95% CI = 1.1-2.5). However, only 25% of the cases had ever been on sick leave due to neck pain. CONCLUSIONS: Neck pain is common among helicopter pilots, and certain factors are identified for use in risk reduction. The link between cases with frequent pain and reported interference with flying duty highlights the need for early prevention of neck pain when planning and implementing helicopter pilots' health care. More clinical trials of good design are required.     

高性能战斗机飞行员选拔体检结果分析

目的 了解当前歼击机飞行员身体状况，进一步搞好高性能战斗机飞行员航空卫生保障工作。方法 对多个部队共计246名歼击机飞行员进行全面的临床体检和离心机 Gz耐力检查，确定飞行结论，并对结果进行统计分析比较。结果 评定飞行合格233人，占总人数的94．7％；飞行暂不合格13人，其中内科7人，外科2人，眼科3人，耳鼻喉科1人。少数飞行员患有活动性疾病仍在队飞行。心血管、消化系统疾病及脊柱疾患的检出率较高。有十分之一飞行员加速度耐力低下。结论 为适应高性能战斗机飞行员航空卫生保障工作的要求，要进一步加强飞行员各级体检工作，杜绝患有活动性疾病飞行员在队飞行，重点防治心血管、消化系统疾病。在招飞体检中，加强脊柱疾患的检查。迫切需要制定高G抗荷训练方案，以提高歼击机飞行员 Gz耐力。