Objective:To evaluate the effectiveness of anti-G straining maneuver (AGSM) in pilots by surface electromyography (sEMG), and to explore the relationships between characteristics of sEMG and anti-G endurance in pilots.Methods:Thirty-eight male high-performance fighter pilots who completed the human centrifuge test at the Air Force Medical Center were selected. Among them, 25 completed the 8.0 G for 10 s anti-G endurance test and 13 completed the 9.0 G for 10 s anti-G endurance test. The sEMG tester was used to keep track of the changes of sEMG in rectus abdominis, rectus femoris, anterior tibial and gastrocnemius muscles while pilots were engaged in AGSM. The anti-G endurance was evaluated according to the changes of visual fields and consciousness. The pilots were divided into 3 groups: the good vision and consciousness group, peripheral visual field narrowing group and endurance endpoint group. The differences in the integral electromyogram (iEMG), mean power frequency (MPF) and muscle input rates between the 3 groups were investigated.Results:A total of 25 pilots completed the 8.0 G for 10 s anti-G endurance test. Among them, 8 (32.0%) were in the good vision and consciousness group, 13 (52.0%) in the peripheral visual field narrowing group and 4 (16.0%) reached the endurance endpoint. Among the 13 pilots who completed the 9.0 G for 10 s anti-G endurance test, 3 (23.1%) were in the good vision and consciousness group, 6 (46.1%) in the peripheral visual field narrowing group, and 4 (30.8%) in the endurance endpoint group. The results of sEMG showed that the iEMG values of the anterior tibialis muscle in pilots under the 9.0 G for 10 s load were significantly different across endurance groups ( H=7.54, P=0.023), and that the iEMG values of the tibialis anterior muscle in the good vision and consciousness group were higher than those in the endurance endpoint group ( P=0.036). The negative slopes of MPF for the rectus abdominis, rectus femoris, anterior tibialis, and gastrocnemius muscles were higher in the good vision and consciousness group than in the other 2 groups, but the differences were not statistically significant ( P>0.05). During the 8.0 G for 10 s anti-G endurance test, there were significant differences in lower limb muscle contribution rates between the 3 groups ( F=4.19, P=0.029). The endurance endpoint group exhibited a lower contribution rate than the good vision and consciousness group ( P=0.025). During the 9.0 G for 10 s anti-G endurance test, there were significant differences in tibialis anterior muscle contribution rates between the 3 groups ( F=4.16, P=0.049). The endurance endpoint group demonstrated a lower contribution rate than the good vision and consciousness group ( P=0.049). Conclusions:The full and balanced activation of abdominal muscles and lower limb muscles, especially the effective mobilization of calf muscles, plays a pivotal role in improving pilots′ AGSM efficiency in high G environments.

Objective:To find out whether the performance of a China-made high performance human centrifuge can satisfy the need of high G training by conducting physiological experiments.Methods:The dynamic physical performance of the anti-G equipment with the human centrifuge was tested before 5 subjects underwent the gradual-onset rate (GOR) run and rapid onset rate (ROR) run experiments. The G onset rate of GOR was 0.1 G/s. The relaxed G-tolerance under GOR (GOR tolerance 1) and the anti-G straining maneuver aided G-tolerance under GOR (GOR tolerance 2) were tested respectively. The G onset rate of ROR was 3 G/s, and the closed-loop mode and pre-programed mode were employed respectively. The closed-loop mode involved 5 G 10 s and 8 G 10 s, where the subjects were required to manipulate the joystick to ensure that the real-time curve of the load matched the target curve. In the pre-programmed mode, the subjects were exposed to 8 G 10 s passively, without any operation requirements. A subjective evaluation form was filled out by subjects after the experiments, in which the 14 indexes for evaluation were about the gondola facilities and environment, running processes, medical monitoring and overall assessment.Results:Both the oxygen mask and anti-G suit achieved full pressurization within 2.0 s. The GOR tolerance 1 was [4.0(3.8, 4.6)] G while the GOR tolerance 2 was (6.2±0.5) G, suggesting a statistically significant difference ( Z=-2.63, P=0.008). The HP anti-G straining maneuver effect was (2.0±0.6) G. All the 5 subjects finished the 5 G 10 s experiment in a closed-loop mode. Three of them attempted 8 G 10 s in the closed-loop mode (1 subject achieved only 7.6 G peak acceleration, and the other 2 achieved full 8 G 10 s exposure), while the remaining 2 completed the 8 G 10 s in the pre-programmed mode. In the closed-loop mode, it was found that the stick force was too strong, the guiding G and real time G curve were not easy to distinguish for some of the subjects because the curve colors were similar, and that the subjects could not see the G curves clearly in case of a grayout. Both seat comfort and the voice quality of communication got the highest subjective assessment score [5.0(4.0, 5.0)] while the sensation of tumble got the lowest score (2.8±0.8). The median or mean scores of other subjective evaluation indexes ranged from 3.0 to 4.6 points. The overall score of subjective assessment was [4.0(3.5, 4.0)] points. Conclusions:The China-made high performance human centrifuge can meet the requirements of 8.0 G high G training, which can be made more effective and comfortable if the strong stick force and feeling of tumble during stop running are overcome.

Objective To investigate the clinical characteristics in an elderly patient with sellar multiple myeloma.Methods Clinical features,laboratory data and radiologic profile of an elderly patient with sellar multiple myeloma were collected.Results The patient was an 85-year-old male.The main clinical manifestations were fatigue,poor appetite and polyuria.Laboratory examinations showed a significant decrease in blood sodium,several anterior pitu-itary hormones and an increase in total protein,mass of pituitary lesion and concentration of prolactin.During etio-logical screening,it was found that the blood immunoglobulin G(IgG)level was significantly increased,the blood M protein was positive and the bone marrow smear showed myeloma cells accompanied by multiple osteolytic lesions in the bones of the whole body.Considering the diagnosis of multiple myeloma,the pituitary lesion was likely to be the extra-medullary involvement.Conclusions The intrasellar plasmacytoma is not common.The disease onset is insidious with clinical features and imaging findings lacking specificity.Therefore,diagnosis relies on biopsy which poses risks for elderly patients and increases diagnostic challenges leading to misdiagnosis.

Objective:To evaluate the effectiveness of anti-G straining maneuver (AGSM) in pilots by surface electromyography (sEMG), and to explore the relationships between characteristics of sEMG and anti-G endurance in pilots.Methods:Thirty-eight male high-performance fighter pilots who completed the human centrifuge test at the Air Force Medical Center were selected. Among them, 25 completed the 8.0 G for 10 s anti-G endurance test and 13 completed the 9.0 G for 10 s anti-G endurance test. The sEMG tester was used to keep track of the changes of sEMG in rectus abdominis, rectus femoris, anterior tibial and gastrocnemius muscles while pilots were engaged in AGSM. The anti-G endurance was evaluated according to the changes of visual fields and consciousness. The pilots were divided into 3 groups: the good vision and consciousness group, peripheral visual field narrowing group and endurance endpoint group. The differences in the integral electromyogram (iEMG), mean power frequency (MPF) and muscle input rates between the 3 groups were investigated.Results:A total of 25 pilots completed the 8.0 G for 10 s anti-G endurance test. Among them, 8 (32.0%) were in the good vision and consciousness group, 13 (52.0%) in the peripheral visual field narrowing group and 4 (16.0%) reached the endurance endpoint. Among the 13 pilots who completed the 9.0 G for 10 s anti-G endurance test, 3 (23.1%) were in the good vision and consciousness group, 6 (46.1%) in the peripheral visual field narrowing group, and 4 (30.8%) in the endurance endpoint group. The results of sEMG showed that the iEMG values of the anterior tibialis muscle in pilots under the 9.0 G for 10 s load were significantly different across endurance groups ( H=7.54, P=0.023), and that the iEMG values of the tibialis anterior muscle in the good vision and consciousness group were higher than those in the endurance endpoint group ( P=0.036). The negative slopes of MPF for the rectus abdominis, rectus femoris, anterior tibialis, and gastrocnemius muscles were higher in the good vision and consciousness group than in the other 2 groups, but the differences were not statistically significant ( P>0.05). During the 8.0 G for 10 s anti-G endurance test, there were significant differences in lower limb muscle contribution rates between the 3 groups ( F=4.19, P=0.029). The endurance endpoint group exhibited a lower contribution rate than the good vision and consciousness group ( P=0.025). During the 9.0 G for 10 s anti-G endurance test, there were significant differences in tibialis anterior muscle contribution rates between the 3 groups ( F=4.16, P=0.049). The endurance endpoint group demonstrated a lower contribution rate than the good vision and consciousness group ( P=0.049). Conclusions:The full and balanced activation of abdominal muscles and lower limb muscles, especially the effective mobilization of calf muscles, plays a pivotal role in improving pilots′ AGSM efficiency in high G environments.

Objective:To find out whether the performance of a China-made high performance human centrifuge can satisfy the need of high G training by conducting physiological experiments.Methods:The dynamic physical performance of the anti-G equipment with the human centrifuge was tested before 5 subjects underwent the gradual-onset rate (GOR) run and rapid onset rate (ROR) run experiments. The G onset rate of GOR was 0.1 G/s. The relaxed G-tolerance under GOR (GOR tolerance 1) and the anti-G straining maneuver aided G-tolerance under GOR (GOR tolerance 2) were tested respectively. The G onset rate of ROR was 3 G/s, and the closed-loop mode and pre-programed mode were employed respectively. The closed-loop mode involved 5 G 10 s and 8 G 10 s, where the subjects were required to manipulate the joystick to ensure that the real-time curve of the load matched the target curve. In the pre-programmed mode, the subjects were exposed to 8 G 10 s passively, without any operation requirements. A subjective evaluation form was filled out by subjects after the experiments, in which the 14 indexes for evaluation were about the gondola facilities and environment, running processes, medical monitoring and overall assessment.Results:Both the oxygen mask and anti-G suit achieved full pressurization within 2.0 s. The GOR tolerance 1 was [4.0(3.8, 4.6)] G while the GOR tolerance 2 was (6.2±0.5) G, suggesting a statistically significant difference ( Z=-2.63, P=0.008). The HP anti-G straining maneuver effect was (2.0±0.6) G. All the 5 subjects finished the 5 G 10 s experiment in a closed-loop mode. Three of them attempted 8 G 10 s in the closed-loop mode (1 subject achieved only 7.6 G peak acceleration, and the other 2 achieved full 8 G 10 s exposure), while the remaining 2 completed the 8 G 10 s in the pre-programmed mode. In the closed-loop mode, it was found that the stick force was too strong, the guiding G and real time G curve were not easy to distinguish for some of the subjects because the curve colors were similar, and that the subjects could not see the G curves clearly in case of a grayout. Both seat comfort and the voice quality of communication got the highest subjective assessment score [5.0(4.0, 5.0)] while the sensation of tumble got the lowest score (2.8±0.8). The median or mean scores of other subjective evaluation indexes ranged from 3.0 to 4.6 points. The overall score of subjective assessment was [4.0(3.5, 4.0)] points. Conclusions:The China-made high performance human centrifuge can meet the requirements of 8.0 G high G training, which can be made more effective and comfortable if the strong stick force and feeling of tumble during stop running are overcome.

Objective To establish a scientific training program that takes into account both anaerobic and aerobic training for pilots,and to explore the appropriate ratio of aerobic and anaerobic training.Methods According to the physical examination standards for pilots,a total of 16 healthy subjects aged 18-24 were selected from two batches.The two batches of subjects were trained with different aerobic and anaerobic ratios.Training period was 3 months.The changes in cardiopulmonary function of the subjects before and after training were evaluated using the cardiopulmonary function exercise testing system(CPET),and the changes in anaerobic capacity were evaluated using changes in strength as an indicator.Results After training,the weight load of the subjects in the two training programs,including barbell squats,leg flexion and hard pull,and barbell under 10RM and 3RM,was significantly increased(P<0.001),and there was no statistically significant difference in anaerobic strength growth between the two groups.The results of CPET showed that the maximum load,maximum heart rate,and respiratory quotient in the two groups were significantly increased after than before the training(P<0.01).The maximum load(Experiment group 1:29.12±19.69,Experiment group 2:72.00±46.24)and respiratory quotient(Experiment grouop 1:0.11±0.09,Experiment group 2:0.28±0.16)of the subjects in experiment group 2 before and after training were greater than those in experiment group 1.The difference was statistically significant(P<0.05).Conclusion The anaerobic and aerobic capacities of the subjects in the experiment group 2 are effectively improved,indicating that ratio of aerobic and anaerobic of the training scheme is better.

Objective:To discuss the application of gradual-onset rate run (GOR) of human centrifuge on G-tolerance evaluation and training by analyzing the training results of (student) pilots in GOR centrifuge run.Methods:The G-tolerance and anti-G straining maneuver effect of 440 student pilots and 368 pilots participated centrifuge training in recent years were analyzed. The (student) pilots were grouped by age (20-25 years,26-30 years,31-35 years,36-40 years, >40 years). The 392 student pilots and 335 pilots who completed rapid onset rate run (ROR) were divided into 8 G 10 s training high G tolerance group (group A), 8 G 10 s training low G tolerance group (group B), 9 G 10 s training high G tolerance group (group C) and 9 G 10 s training low G tolerance group (group D) according to pass the 8 G 10 s or 9 G 10 s run one-time or not. The relation of G-tolerance and anti-G straining maneuver effect of GOR to ROR was discussed.Results:The average distribution range of relaxed G-tolerance under GOR (GOR tolerance 1) was (4.1±0.7) G, and the average distribution range of anti-G straining maneuver aided G-tolerance under GOR (GOR tolerance 2) was (6.2±0.8) G. The average HP anti-G straining maneuver effect was (2.1±0.6) G. There was a significant difference in GOR tolerance 1 ( H=11.94, P=0.018), no significant difference in GOR tolerance 2 ( H=4.80, P=0.308), and a significant difference in the effect of HP anti-G straining maneuver among pilots in different age groups ( F=3.01, P=0.018). The effect of HP anti-G straining maneuver in the age group over 40 years old was greater than that in other age groups ( P=0.027, 0.034, 0.009, 0.006). There was no significant difference in GOR tolerance 1, GOR tolerance 2 and HP anti-G straining maneuver effect between pilots and student pilots (all P>0.05). There were significant differences in GOR tolerance 2 ( H=15.38, P=0.002) and the effect of HP anti-G straining maneuver ( H=8.22, P=0.041) among group A, group B, group C and group D. The GOR tolerance 2 of group B was lower than that of other anti-G tolerance groups ( P=0.003, 0.001, 0.040). Conclusions:The centrifuge GOR training could reflect the G-tolerance and anti-G straining maneuver effect of (student) pilots and provide references for predicting the human centrifuge training result and improving accelerate training and tolerance evaluating.

Objective:To explore whether Corona Virus Disease 2019 (COVID-19) has any impact on human centrifuge training of flying cadets and to provide references to the human centrifuge training for the recovered flying personnel by comparing the changes of flying cadets′ G-tolerance and physiological indicators in human centrifuge training.Methods:Twelve flying cadets who underwent the current batch of human centrifuge training in 2022 were selected and divided into rehabilitation group and control group according to whether they had been infected with COVID-19, with 6 in each group. The rapid G onset rate (ROR) and gradual G onset rate (GOR) were respectively chosen for human centrifuge test. At the same time, the changes of their heart rate and respiratory rate during the tests were recorded, and the G-tolerance situations of the subjects were collected.Results:The average relaxed G-tolerance under GOR (GOR tolerance 1) was (4.2±0.8) G in rehabilitation group, and their average anti-G straining maneuver aided G-tolerance under GOR (GOR tolerance 2) was (5.7±0.6) G. Compared with that of the control group, there was no significant difference in GOR tolerance 1 and GOR tolerance 2 (both P>0.05). There was no significant changes in heart rate and respiratory rate in ROR and GOR human centrifuge tests between 2 groups (all P>0.05). Conclusions:COVID-19 didn't impact the recovered flying cadets' performance in human centrifuge training, as well as the anti-G straining maneuver effect and cardiovascular regulation.

Objective:To discuss the application of gradual-onset rate run (GOR) of human centrifuge on G-tolerance evaluation and training by analyzing the training results of (student) pilots in GOR centrifuge run.Methods:The G-tolerance and anti-G straining maneuver effect of 440 student pilots and 368 pilots participated centrifuge training in recent years were analyzed. The (student) pilots were grouped by age (20-25 years,26-30 years,31-35 years,36-40 years, >40 years). The 392 student pilots and 335 pilots who completed rapid onset rate run (ROR) were divided into 8 G 10 s training high G tolerance group (group A), 8 G 10 s training low G tolerance group (group B), 9 G 10 s training high G tolerance group (group C) and 9 G 10 s training low G tolerance group (group D) according to pass the 8 G 10 s or 9 G 10 s run one-time or not. The relation of G-tolerance and anti-G straining maneuver effect of GOR to ROR was discussed.Results:The average distribution range of relaxed G-tolerance under GOR (GOR tolerance 1) was (4.1±0.7) G, and the average distribution range of anti-G straining maneuver aided G-tolerance under GOR (GOR tolerance 2) was (6.2±0.8) G. The average HP anti-G straining maneuver effect was (2.1±0.6) G. There was a significant difference in GOR tolerance 1 ( H=11.94, P=0.018), no significant difference in GOR tolerance 2 ( H=4.80, P=0.308), and a significant difference in the effect of HP anti-G straining maneuver among pilots in different age groups ( F=3.01, P=0.018). The effect of HP anti-G straining maneuver in the age group over 40 years old was greater than that in other age groups ( P=0.027, 0.034, 0.009, 0.006). There was no significant difference in GOR tolerance 1, GOR tolerance 2 and HP anti-G straining maneuver effect between pilots and student pilots (all P>0.05). There were significant differences in GOR tolerance 2 ( H=15.38, P=0.002) and the effect of HP anti-G straining maneuver ( H=8.22, P=0.041) among group A, group B, group C and group D. The GOR tolerance 2 of group B was lower than that of other anti-G tolerance groups ( P=0.003, 0.001, 0.040). Conclusions:The centrifuge GOR training could reflect the G-tolerance and anti-G straining maneuver effect of (student) pilots and provide references for predicting the human centrifuge training result and improving accelerate training and tolerance evaluating.

Objective:To explore whether Corona Virus Disease 2019 (COVID-19) has any impact on human centrifuge training of flying cadets and to provide references to the human centrifuge training for the recovered flying personnel by comparing the changes of flying cadets′ G-tolerance and physiological indicators in human centrifuge training.Methods:Twelve flying cadets who underwent the current batch of human centrifuge training in 2022 were selected and divided into rehabilitation group and control group according to whether they had been infected with COVID-19, with 6 in each group. The rapid G onset rate (ROR) and gradual G onset rate (GOR) were respectively chosen for human centrifuge test. At the same time, the changes of their heart rate and respiratory rate during the tests were recorded, and the G-tolerance situations of the subjects were collected.Results:The average relaxed G-tolerance under GOR (GOR tolerance 1) was (4.2±0.8) G in rehabilitation group, and their average anti-G straining maneuver aided G-tolerance under GOR (GOR tolerance 2) was (5.7±0.6) G. Compared with that of the control group, there was no significant difference in GOR tolerance 1 and GOR tolerance 2 (both P>0.05). There was no significant changes in heart rate and respiratory rate in ROR and GOR human centrifuge tests between 2 groups (all P>0.05). Conclusions:COVID-19 didn't impact the recovered flying cadets' performance in human centrifuge training, as well as the anti-G straining maneuver effect and cardiovascular regulation.