Objective To analysis the relationship between the lactate-to-albumin ratio(LAR)and the 28-day prognosis in patients with sepsis.Methods Based on the Medical Information Mart for Intensive Care-Ⅳ(MIMIC-Ⅳ)database,patients with sepsis aged≥18 years were selected.Patients were divided into survival and death groups according to their 28-day prognosis.The LAR was divided into quartiles:Q1(LAR<0.45),Q2(0.45≤LAR<0.70),Q3(0.70≤LAR<1.18),and Q4(LAR≥1.18);and into two groups based on the median LAR:low LAR group(LAR≤0.70)and high LAR group(LAR>0.70).Demographic characteristics,comorbidities,laboratory indicators,clinical treatments,and disease severity scores of patients were extracted.LAR was included as a continuous variable and a four-category variable in multiple Logistic regression models,with trend tests performed.Subgroup analyses were conducted based on gender,age,comorbidities,and sequential organ failure assessment(SOFA)score.Receiver operator characteristic curve(ROC curves)were plotted to analyze the predictive efficacy of lactate,albumin(Alb),LAR and SOFA score for the prognosis of sepsis patients.Kaplan-Meier survival curves were plotted to compare the difference of 28-day cumulative survival rates of sepsis patients in the high and low LAR groups.Results A total of 9 169 patients with sepsis were included,with 6 799 in the survival group and 2 370 in the death group.Compared with the survival group,the death group had older age[years:70.80(58.64,82.25)vs.65.07(53.56,76.92)],higher levels of potassium,creatinine,blood urea nitrogen(BUN),white blood cell count(WBC),lactate,LAR,SOFA score,simplified acute physiology scoreⅡ(SAPSⅡ),and higher proportions of chronic obstructive pulmonary disease(COPD),heart failure,use of vasopressors within 48 hours,and continuous renal replacement therapy(CRRT)[potassium(mmol/L):5.0(4.5,5.7)vs.4.8(4.4,5.4),creatinine(μmol/L):132.60(88.40,212.16)vs.97.24(70.72,159.12),BUN(mmol/L):11.42(7.14,18.56)vs.7.85(5.25,13.57),WBC(×109/L):13.1(8.7,19.1)vs.11.4(7.6,16.4),lactate(mmol/L):2.9(1.8,5.1)vs.2.0(1.4,3.1),LAR:1.03(0.63,1.88)vs.0.62(0.42,0.98),SOFA score:9(6,12)vs.6(4,8),SAPSⅡscore:52(42,64)vs.38(30,47),COPD:8.19%(194/2 370)vs.6.57%(447/6 799),heart failure:29.96%(710/2 370)vs.26.31%(1 789/6 799),use of vasopressors within 48 hours:62.19%(1 474/2 370)vs.37.56%(2 554/6 799),CRRT:19.45%(461/2 370)vs.9.56%(650/6 799),all P<0.05],while lower levels of body weight,chloride,calcium,hemoglobin(Hb),platelet count(PLT),Alb and lower proportions of hypertension were observed in the death group[body weight(kg):75.8(63.6,92.3)vs.78.7(66.5,95.0),chloride(mmol/L):104(98,109)vs.104(100,108),calcium(mmol/L):1.07(1.00,1.15)vs.1.09(1.03,1.15),Hb(g/L):103(87,120)vs.105(90,121),PLT(×109/L):173(104,246)vs.174(118,243),Alb(g/L):29(24,34)vs.33(28,37),hypertension:35.36%(838/2 370)vs.38.34%(2 607/6 799),all P<0.05].In the Logistic regression model adjusted for all confounding factors,the odds ratio(OR)and 95%confidence interval(95%CI)of LAR were 1.74(1.64-1.85),P<0.001;when LAR was treated as a four-category variable,the OR values of Q2,Q3,and Q4 increased progressively compared with Q1,being 1.49(1.22-1.82),2.27(1.88-2.75),and 5.05(4.20-6.08),respectively,P<0.001.Subgroup analyses showed that LAR was an independent risk factor for the 28-day prognosis of sepsis in different subgroups based on gender,age,comorbidities,and SOFA score(all P<0.001),with no interaction effects with the subgroup variables(all P>0.05).ROC curve analysis showed that the AUC of LAR predicted the 28-day prognosis of patients with sepsis was 0.688(0.675-0.700),higher than that of lactate[0.655(0.642-0.668)]and Alb[0.636(0.623-0.649)],both P<0.001,and not significantly lower than that of SOFA score[0.699(0.687-0.712),P=0.108].Kaplan-Meier survival analysis showed that the 28-day cumulative survival rate was significantly higher in the low LAR group than in the high LAR group(Log-Rank test:χ2=533.24,P<0.001).Conclusion LAR is an independent risk factor for the 28-day prognosis of sepsis patients.Higher LAR is associated with adverse outcomes,and its predictive efficacy is superior to that of lactate and albumin.

Objective:To investigate the efficacy of vital pulp therapy versus pulp revascularization in the treatment of irreversible pulpitis and apical periodontitis in young permanent teeth. Methods:This study used a retrospective design. Fifty-six children with irreversible pulpitis and apical periodontitis in young permanent teeth, admitted to Shaoxing Stomatological Hospital from January 2022 to June 2024, were selected for the study. The children were divided into Group A ( n = 28) and Group B ( n = 28) based on treatment methods. Group A received vital pulp therapy, while Group B underwent pulp revascularization. The efficacy of both groups was compared 12 months after surgery. The root length and apical foramen size were compared between the two groups before surgery, as well as 3 and 12 months after surgery. The imaging findings were also compared between the two groups 3 and 12 months after surgery. Results:There was no significant difference in efficacy between the two groups ( P>0.05). The root lengths in Group A at 3 and 12 months after surgery were (13.17 ± 1.52) mm and (14.34 ± 1.68) mm, respectively, which were significantly greater than those in Group B [(11.86 ± 1.29) mm, (13.09 ± 1.45) mm; t = 3.48, 2.98, both P<0.05]. The apical foramen sizes in Group A at 3 and 12 months after surgery were (2.17 ± 0.32) mm and (1.61 ± 0.27) mm, respectively, and were significantly smaller than those in Group B [(2.53 ± 0.37) mm, (1.98 ± 0.31) mm; t = -7.03, -4.76, both P<0.05]. The proportion of children with an open apical foramen in Group A at 3 months after surgery was significantly lower than that in Group B [35.71% (10/28) vs. 64.29% (18/28); χ2 = 4.57, P<0.05). However, there was no statistically significant difference in the proportion of open apical foramina between the two groups at 12 months after surgery ( P>0.05). Conclusions:Vital pulp therapy shows good efficacy in the treatment of irreversible pulpitis and apical periodontitis in young permanent teeth. Compared with pulp revascularization, vital pulp therapy can remarkably reduce apical foramen size and increase root length, making it a valuable option for clinical practice.

Objective To analysis the relationship between the lactate-to-albumin ratio(LAR)and the 28-day prognosis in patients with sepsis.Methods Based on the Medical Information Mart for Intensive Care-Ⅳ(MIMIC-Ⅳ)database,patients with sepsis aged≥18 years were selected.Patients were divided into survival and death groups according to their 28-day prognosis.The LAR was divided into quartiles:Q1(LAR<0.45),Q2(0.45≤LAR<0.70),Q3(0.70≤LAR<1.18),and Q4(LAR≥1.18);and into two groups based on the median LAR:low LAR group(LAR≤0.70)and high LAR group(LAR>0.70).Demographic characteristics,comorbidities,laboratory indicators,clinical treatments,and disease severity scores of patients were extracted.LAR was included as a continuous variable and a four-category variable in multiple Logistic regression models,with trend tests performed.Subgroup analyses were conducted based on gender,age,comorbidities,and sequential organ failure assessment(SOFA)score.Receiver operator characteristic curve(ROC curves)were plotted to analyze the predictive efficacy of lactate,albumin(Alb),LAR and SOFA score for the prognosis of sepsis patients.Kaplan-Meier survival curves were plotted to compare the difference of 28-day cumulative survival rates of sepsis patients in the high and low LAR groups.Results A total of 9 169 patients with sepsis were included,with 6 799 in the survival group and 2 370 in the death group.Compared with the survival group,the death group had older age[years:70.80(58.64,82.25)vs.65.07(53.56,76.92)],higher levels of potassium,creatinine,blood urea nitrogen(BUN),white blood cell count(WBC),lactate,LAR,SOFA score,simplified acute physiology scoreⅡ(SAPSⅡ),and higher proportions of chronic obstructive pulmonary disease(COPD),heart failure,use of vasopressors within 48 hours,and continuous renal replacement therapy(CRRT)[potassium(mmol/L):5.0(4.5,5.7)vs.4.8(4.4,5.4),creatinine(μmol/L):132.60(88.40,212.16)vs.97.24(70.72,159.12),BUN(mmol/L):11.42(7.14,18.56)vs.7.85(5.25,13.57),WBC(×109/L):13.1(8.7,19.1)vs.11.4(7.6,16.4),lactate(mmol/L):2.9(1.8,5.1)vs.2.0(1.4,3.1),LAR:1.03(0.63,1.88)vs.0.62(0.42,0.98),SOFA score:9(6,12)vs.6(4,8),SAPSⅡscore:52(42,64)vs.38(30,47),COPD:8.19%(194/2 370)vs.6.57%(447/6 799),heart failure:29.96%(710/2 370)vs.26.31%(1 789/6 799),use of vasopressors within 48 hours:62.19%(1 474/2 370)vs.37.56%(2 554/6 799),CRRT:19.45%(461/2 370)vs.9.56%(650/6 799),all P<0.05],while lower levels of body weight,chloride,calcium,hemoglobin(Hb),platelet count(PLT),Alb and lower proportions of hypertension were observed in the death group[body weight(kg):75.8(63.6,92.3)vs.78.7(66.5,95.0),chloride(mmol/L):104(98,109)vs.104(100,108),calcium(mmol/L):1.07(1.00,1.15)vs.1.09(1.03,1.15),Hb(g/L):103(87,120)vs.105(90,121),PLT(×109/L):173(104,246)vs.174(118,243),Alb(g/L):29(24,34)vs.33(28,37),hypertension:35.36%(838/2 370)vs.38.34%(2 607/6 799),all P<0.05].In the Logistic regression model adjusted for all confounding factors,the odds ratio(OR)and 95%confidence interval(95%CI)of LAR were 1.74(1.64-1.85),P<0.001;when LAR was treated as a four-category variable,the OR values of Q2,Q3,and Q4 increased progressively compared with Q1,being 1.49(1.22-1.82),2.27(1.88-2.75),and 5.05(4.20-6.08),respectively,P<0.001.Subgroup analyses showed that LAR was an independent risk factor for the 28-day prognosis of sepsis in different subgroups based on gender,age,comorbidities,and SOFA score(all P<0.001),with no interaction effects with the subgroup variables(all P>0.05).ROC curve analysis showed that the AUC of LAR predicted the 28-day prognosis of patients with sepsis was 0.688(0.675-0.700),higher than that of lactate[0.655(0.642-0.668)]and Alb[0.636(0.623-0.649)],both P<0.001,and not significantly lower than that of SOFA score[0.699(0.687-0.712),P=0.108].Kaplan-Meier survival analysis showed that the 28-day cumulative survival rate was significantly higher in the low LAR group than in the high LAR group(Log-Rank test:χ2=533.24,P<0.001).Conclusion LAR is an independent risk factor for the 28-day prognosis of sepsis patients.Higher LAR is associated with adverse outcomes,and its predictive efficacy is superior to that of lactate and albumin.

Objective:To investigate the efficacy of vital pulp therapy versus pulp revascularization in the treatment of irreversible pulpitis and apical periodontitis in young permanent teeth. Methods:This study used a retrospective design. Fifty-six children with irreversible pulpitis and apical periodontitis in young permanent teeth, admitted to Shaoxing Stomatological Hospital from January 2022 to June 2024, were selected for the study. The children were divided into Group A ( n = 28) and Group B ( n = 28) based on treatment methods. Group A received vital pulp therapy, while Group B underwent pulp revascularization. The efficacy of both groups was compared 12 months after surgery. The root length and apical foramen size were compared between the two groups before surgery, as well as 3 and 12 months after surgery. The imaging findings were also compared between the two groups 3 and 12 months after surgery. Results:There was no significant difference in efficacy between the two groups ( P>0.05). The root lengths in Group A at 3 and 12 months after surgery were (13.17 ± 1.52) mm and (14.34 ± 1.68) mm, respectively, which were significantly greater than those in Group B [(11.86 ± 1.29) mm, (13.09 ± 1.45) mm; t = 3.48, 2.98, both P<0.05]. The apical foramen sizes in Group A at 3 and 12 months after surgery were (2.17 ± 0.32) mm and (1.61 ± 0.27) mm, respectively, and were significantly smaller than those in Group B [(2.53 ± 0.37) mm, (1.98 ± 0.31) mm; t = -7.03, -4.76, both P<0.05]. The proportion of children with an open apical foramen in Group A at 3 months after surgery was significantly lower than that in Group B [35.71% (10/28) vs. 64.29% (18/28); χ2 = 4.57, P<0.05). However, there was no statistically significant difference in the proportion of open apical foramina between the two groups at 12 months after surgery ( P>0.05). Conclusions:Vital pulp therapy shows good efficacy in the treatment of irreversible pulpitis and apical periodontitis in young permanent teeth. Compared with pulp revascularization, vital pulp therapy can remarkably reduce apical foramen size and increase root length, making it a valuable option for clinical practice.

Objective To explore the feasibility and rationality of advanced integrated two-stage laparoscopic simulation training course in standardized training of surgical residents.Methods From December 2019 to December 2021,the advanced integrated two-stage laparoscopic simulation training course was carried out among 2019-2020 surgical residents who received standardized training in our hospital.The course was divided into two stages.In the first stage,BEST(best essential surgical technology training)course,adopted Darwin? endoscopic training system,Tianyan? endoscopic training system,Microport? 3D laparoscopic training system and simple simulative models were used.The second stage,BEST PLUS course,same platform as that in BEST course and in vitro animal models were used.The questionnaire survey method(before and after class questionnaire)was adopted to evaluate the curriculum setting,such as curriculum form,simulators,teaching method,time arrangement,curriculum difficulty,training effect,curriculum satisfaction and so on.Results A total of 37 surgical residents completed the two-stage course training and the questionnaire survey.The overall satisfaction rate with the curriculum setting was 100%.There were 32 residents(86.5%)thought that first stage training course could significantly improve their clinical skills,35 residents(94.6%)thought that second stage training course could significantly improve their clinical skills,and 36 resident(97.3%)thought that the first stage curriculum could significantly help them improve performance in the second stage curriculum.Conclusions The trainees had a high degree of recognition and satisfaction for the advanced integrated two-stage laparoscopic simulation training course.The overall design of course was reasonable and feasible,and was attractive to trainees.

Objective:To provide theoretical basis for strength and endurance training of waist and abdominal muscles and prevention of waist injuries in fighter pilots by exploring the muscle strength and work characteristics of the waist and abdominal flexor and extensor muscles in fighter pilots.Methods:Sixty male fighter pilots who were qualified for flight in aeromedical assessment, aged 24-46 years old, were randomly selected and divided into 24-30, 31-40, 41-46 years group. The Isomed2000 isokinetic dynamometer system was applied to measure the muscle strength and work performance of the abdominal and lumbar flexors and extensors of the fighter pilots with the angular velocities of 60°/s and 180°/s. The flexion and extension muscle peak torque, relative peak torque, flexion-extension ratio, and endurance ratio were compared among different age groups of pilots.Results:At the same angular velocity, the peak torque and relative peak torque of the lumbar and abdominal extensor muscles in fighter pilots were greater than those of the flexor muscles, with statistically significant differences ( t=7.01-9.13, all P<0.001). The peak torque and relative peak torque of the lumbar and abdominal flexor and extensor muscles significantly decreased with increasing test angular velocity ( t=13.63-17.25, all P<0.001). Under the angular velocity of 60°/s, there were no significant differences in the peak torque and relative peak torque of the flexor muscles among different age groups (both P>0.05); there were significant differences in the peak torque and relative peak torque of extensor muscles ( F=5.31, 6.61, P=0.008, 0.003) and 41-46 years groups were lower than the other 2 groups ( P=0.019, 0.003, 0.002, 0.004). Under an angular velocity of 180°/s, there were significant differences in the peak torque and relative peak torque of the waist and abdominal flexor and extensor muscles among different age groups ( F=3.82, 3.47, 3.83, 5.49, P=0.028, 0.043, 0.027, 0.008); the relative peak torque of the abdominal and lumbar flexor and extensor muscles in the 24-30 years group was higher than that in the 41-46 years group ( P=0.032, 0.006). The peak torque and the relative peak torque of the abdominal and lumbar flexor muscles in 31-40 years group were higher than those in 41-46 years group ( P=0.008, 0.013). The low qualification rate of peak torque ratio indicated the imbalance between flexor and extensor muscles and the poor endurance of abdominal and lumbar flexor and extensor muscles than that of flexor muscles. There was no statistically significant difference in the endurance ratio of the abdominal and lumbar flexor and extensor muscles among different age groups ( P>0.05). Conclusions:The balance between flexor and extensor muscles of waist and abdominal muscles should be paid more in fighter pilot′s fitness training. For the pilots older than 40 the training targeted to slow the muscles decline is necessary.

Objective:To investigate the status of hepatitis E virus infection in unpaid blood donors in Wenzhou.Methods:A total of 5 241 blood samples were selected from donors who successfully donated blood between October 2022 and March 2023. These samples were tested for hepatitis E virus (HEV) through HEV-IgG antibodies, HEV-IgM antibodies, and nucleic acid tests (HEV RNA). Samples that tested positive for HEV RNA underwent quantitative detection and sequencing. Data regarding the blood donors were collected, the positive rates of each test result were recorded, and the HEV infection status among different populations was analyzed.Results:The positive rate of the HEV-IgG antibody test was 23.60% (1 237/5 241), while the positive rate of the HEV-IgM antibody test was 0.29% (15/5 241). The positive rate of the HEV RNA test was 0.08% (4/5 241). The positive rate of the HEV-IgG test increased with age ( χ2 = 379.493, P < 0.05), and males had a higher positive rate than females ( χ2 = 5.12, P < 0.05). Both the positive rates of HEV-IgG and HEV-IgM tests increased as the number of blood donations increased ( χ2 = 40.87, 8.30, both P < 0.05). Furthermore, the positive rates were significantly higher in 2023 than in 2022 ( χ2 = 51.03, 13.35, both P < 0.05), and they were also significantly higher in spring than in winter ( χ2 = 51.03, 13.35, both P < 0.05). Only one HEV RNA-positive blood donor tested positive for both HEV-IgG and HEV-IgM antibodies, while the remaining three donors tested negative. Only one case was genotyped, and it belonged to genotype Ⅳ. Conclusion:The incidence of HEV infection among unpaid blood donors in Wenzhou of Zhejiang Province is relatively high, with the prevalent HEV genotype being type Ⅳ. Characteristics such as sex, age, and the number of blood donations can be utilized as auxiliary screening reference indicators.

Objective:To identify the independent factors of unplanned interruption during continuous renal replacement therapy (CRRT) and construct a risk prediction model, and to verify the clinical application effectiveness of the model.Methods:A retrospective study was conducted on critically ill adult patients who received CRRT treatment in the intensive care unit (ICU) of Zhejiang Hospital from January 2021 to August 2022 for model construction. According to whether unplanned weaning occurred, the patients were divided into two groups. The potential influencing factors of unplanned CRRT weaning in the two groups were compared. The independent influencing factors of unplanned CRRT weaning were screened by binary Logistic regression and a risk prediction model was constructed. The goodness of fit of the model was verified by a Hosmer-Lemeshow test and its predictive validity was evaluated by receiver operator characteristic curve (ROC curve). Then embed the risk prediction model into the hospital's ICU multifunctional electronic medical record system for severe illness, critically ill patients with CRRT admitted to the ICU of Zhejiang Hospital from November 2022 to October 2023 were prospectively analyzed to verify the model's clinical application effect.Results:① Model construction and internal validation: a total of 331 critically ill patients with CRRT were included to be retrospectively analyzed. Among them, there were 238 patients in planned interruption group and 93 patients in unplanned interruption group. Compared with the planned interruption group, the unplanned interruption group was shown as a lower proportion of males (80.6% vs. 91.6%) and a higher proportion of chronic diseases (60.2% vs. 41.6%), poor blood purification catheter function (31.2% vs. 6.3%), as a higher platelet count (PLT) before CRRT initiation [×10 9/L: 137 (101, 187) vs. 109 (74, 160)], lower level of blood flow rate [mL/min: 120 (120, 150) vs. 150 (140, 180)], higher proportion of using pre-dilution (37.6% vs. 23.5%), higher filtration fraction [23.0% (17.5%, 32.9%) vs. 19.1% (15.7%, 22.6%)], and frequency of blood pump stops [times: 19 (14, 21) vs. 9 (6, 13)], the differences of the above 8 factors between the two groups were statistically significant (all P < 0.05). Binary Logistic regression analysis showed that chronic diseases [odds ratio ( OR) = 3.063, 95% confidence interval (95% CI) was 1.200-7.819], blood purification catheter function ( OR = 4.429, 95% CI was 1.270-15.451), blood flow rate ( OR = 0.928, 95% CI was 0.900-0.957), and frequency of blood pump stops ( OR = 1.339, 95% CI was 1.231-1.457) were the independent factors for the unplanned interruption of CRRT (all P < 0.05). These 4 factors were used to construct a risk prediction model, and ROC curve analysis showed that the area under the curve (AUC) predicted by the model was 0.952 (95% CI was 0.930-0.973, P = 0.003 0), with a sensitivity of 88.2%, a specificity of 89.9%, and a maximum value of 1.781 for the Youden index. ② External validation: prospective inclusion of 110 patients, including 63 planned interruption group and 47 unplanned interruption group. ROC curve analysis showed that the AUC of the risk prediction model was 0.919 (95% CI was 0.870-0.969, P = 0.004 3), with a sensitivity of 91.5%, a specificity of 79.4%, and a maximum value of the Youden index of 1.709. Conclusion:The risk prediction model for unplanned interruption during CRRT has a high predictive efficiency, allowing for rapid and real-time identification of the high risk patients, thus providing references for preventative nursing.

Objective:To preliminarily explore the zoning of inflammatory lesions in patients with acute necrotizing pancreatitis (ANP) based on the peripancreatic membrane anatomy, and its impact on treatment outcome of ANP.Methods:Clinical data of 197 patients with ANP treated at Hunan Provincial People's Hospital from January 2021 to June 2022 were retrospectively analyzed, including 133 males and 64 females, aged (47.2±13.3) years old. Basic information, characteristics of pancreatitis, and imaging data were collected. The inflammatory lesions were partitioned based on the peripancreatic membrane anatomy. Patients were followed-up via outpatient visits or telephone reviews. According to the prognosis, patients were divided into the poor-prognosis group ( n=93), including patients with postoperative multi-organ failure, severe local complications, and death; and the non-poor-prognosis group ( n=104), including patients without these adverse outcomes. Multivariate logistic regression analysis was used to identify factors influencing prognosis. Receiver operating characteristic (ROC) curves were plotted to assess the predictive power of the number of involved regions for poor prognosis. Results:The inflammatory lesions of pancreas were divided into 13 regions: the lesser sac, pancreatic head and duodenum, left anterior renal, right anterior renal, left posterior renal, right posterior renal, left perirenal fat sac, right perirenal fat sac, left lateral abdominal wall, right lateral abdominal wall, left pelvic wall, right pelvic wall, and other regions. Significant differences were observed between the poor-prognosis group and the non-poor-prognosis group in terms of body mass index (BMI), pancreatic necrosis area, and the number of inflammatory lesion regions (all P<0.05). Multivariate logistic regression analysis showed that high BMI ( OR=1.723, 95% CI: 1.457-2.038, P<0.001), pancreatic necrosis area ≥50% ( OR=3.221, 95% CI: 1.073-9.668, P=0.037), and a higher number of inflammatory lesion regions ( OR=1.388, 95% CI: 1.110-1.735, P=0.004) were associated with a higher risk of poor prognosis in patients with ANP. Based on the number of inflammatory lesion regions, the ROC curve analysis revealed that the optimal cut-off value was 5.5 for predicting poor prognosis in patients with ANP, with an area under the curve of 0.747(95% CI: 0.680-0.815) and a sensitivity and specificity of 0.387 and 0.962, respectively. Conclusion:The peripancreatic membrane anatomy facilitates a relatively fixed partitioning of inflammatory lesions in patients with acute necrotizing pancreatitis, and the number of inflammatory lesion regions is associated with poor prognosis.

Objective:To provide theoretical basis for strength and endurance training of waist and abdominal muscles and prevention of waist injuries in fighter pilots by exploring the muscle strength and work characteristics of the waist and abdominal flexor and extensor muscles in fighter pilots.Methods:Sixty male fighter pilots who were qualified for flight in aeromedical assessment, aged 24-46 years old, were randomly selected and divided into 24-30, 31-40, 41-46 years group. The Isomed2000 isokinetic dynamometer system was applied to measure the muscle strength and work performance of the abdominal and lumbar flexors and extensors of the fighter pilots with the angular velocities of 60°/s and 180°/s. The flexion and extension muscle peak torque, relative peak torque, flexion-extension ratio, and endurance ratio were compared among different age groups of pilots.Results:At the same angular velocity, the peak torque and relative peak torque of the lumbar and abdominal extensor muscles in fighter pilots were greater than those of the flexor muscles, with statistically significant differences ( t=7.01-9.13, all P<0.001). The peak torque and relative peak torque of the lumbar and abdominal flexor and extensor muscles significantly decreased with increasing test angular velocity ( t=13.63-17.25, all P<0.001). Under the angular velocity of 60°/s, there were no significant differences in the peak torque and relative peak torque of the flexor muscles among different age groups (both P>0.05); there were significant differences in the peak torque and relative peak torque of extensor muscles ( F=5.31, 6.61, P=0.008, 0.003) and 41-46 years groups were lower than the other 2 groups ( P=0.019, 0.003, 0.002, 0.004). Under an angular velocity of 180°/s, there were significant differences in the peak torque and relative peak torque of the waist and abdominal flexor and extensor muscles among different age groups ( F=3.82, 3.47, 3.83, 5.49, P=0.028, 0.043, 0.027, 0.008); the relative peak torque of the abdominal and lumbar flexor and extensor muscles in the 24-30 years group was higher than that in the 41-46 years group ( P=0.032, 0.006). The peak torque and the relative peak torque of the abdominal and lumbar flexor muscles in 31-40 years group were higher than those in 41-46 years group ( P=0.008, 0.013). The low qualification rate of peak torque ratio indicated the imbalance between flexor and extensor muscles and the poor endurance of abdominal and lumbar flexor and extensor muscles than that of flexor muscles. There was no statistically significant difference in the endurance ratio of the abdominal and lumbar flexor and extensor muscles among different age groups ( P>0.05). Conclusions:The balance between flexor and extensor muscles of waist and abdominal muscles should be paid more in fighter pilot′s fitness training. For the pilots older than 40 the training targeted to slow the muscles decline is necessary.