The incidence of military training-related injuries in Chinese new recruits: a systematic review and meta-analysis

Total body water percentage and 3rd space water are novel risk factors for training-related lower extremity muscle injuries in young males

PURPOSE

To identify the risk factors for training-related lower extremity muscle injuries in young males by a non-invasive method of body composition analysis.

METHODS

A total of 282 healthy young male volunteers aged 18 - 20 years participated in this cohort study. Injury location, degree, and injury rate were adjusted by a questionnaire based on the overuse injury assessment methods used in epidemiological studies of sports injuries. The occurrence of training injuries is monitored and diagnosed by physicians and treated accordingly. The body composition was measured using the BodyStat QuadScan 4000 multifrequency Bio-impedance system at 5, 50, 100 and 200 kHz to obtain 4 impedance values. The Shapiro-Wilk test was used to check whether the data conforms to a normal distribution. Data of normal distribution were shown as mean ± SD and analyzed by t-test, while those of non-normal distribution were shown as median (Q1, Q3) and analyzed by Wilcoxon rank sum test. The receiver operator characteristic curve and logistic regression analysis were performed to investigate risk factors for developing training-related lower extremity injuries and accuracy.

RESULTS

Among the 282 subjects, 78 (27.7%) developed training injuries. Lower extremity training injuries revealed the highest incidence, accounting for 23.4 % (66 cases). These patients showed higher percentages of lean body mass (p = 0.001), total body water (TBW, p = 0.006), extracellular water (p = 0.020) and intracellular water (p = 0.010) as well as a larger ratio of basal metabolic rate/total weight (p = 0.006), compared with those without lower extremity muscle injuries. On the contrary, the percentage of body fat (p = 0.001) and body fat mass index (p = 0.002) was lower. Logistic regression analysis showed that TBW percentage > 65.35% (p = 0.050, OR = 3.114) and 3rd space water > 0.95% (p = 0.045, OR = 2.342) were independent risk factors for lower extremity muscle injuries.

CONCLUSION

TBW percentage and 3rd space water measured with bio-impedance method are potential risk factors for predicting the incidence of lower extremity muscle injuries in young males following training.

A biomechanical evaluation of firefighters' musculoskeletal loads when carrying self-contained breathing apparatus in walking and running

INTRODUCTION

Musculoskeletal loading data are needed to design ergonomic intervention for firefighters. This study aimed to quantify the firefighters' musculoskeletal loads during self-contained breathing apparatus (SCBA) carriage and evaluate the effectiveness of shoulder strap length variation for the prevention of SCBA-related injuries.

METHOD

Twelve firefighters (height: 174.6 ± 2.4 cm, mass: 67 ± 3.5 kg, BMI = 22 ± 1 kg/m2) participated the walking and running protocols with no SCBA equipped and three varying-strapped SCBAs conditions. Joint range of motion and surface electromyography (sEMG) were synchronously measured. Subsequently, joint kinematics was inputted for subject-specific musculoskeletal modeling to estimate muscle forces and joint reaction forces, while the sEMG was used to validate the model. Repeated measures analysis of variance was used for the main effects (p < 0.05). Independent samples t-test was performed to determine differences between walking and running.

RESULTS

Walking with SCBA increased the rectus femoris force and hip reaction force by 34.92% [F = 53.629; p < 0.001; η2 = 0.317] and 34.71% [F = 53.653; p < 0.001; η2 = 0.517], the growth rate was 54.2% [F = 76.487; p < 0.001; η2 = 0.418] and 51.19% [F = 69.201; p < 0.001; η2 = 0.652] during running, respectively. Running with SCBA significantly increased the knee reaction force by 63.04% [F = 83.960; p < 0.001; η2 = 0.797], while only 18.49% increase during walking. Adjusting SCBA shoulder strap length significantly altered the rectus abdominis force and L4/L5 reaction force during walking and running.

CONCLUSIONS

Results revealed that rectus femoris activity, hip and knee exertion was sensitive to SCBA carriage. The variation of shoulder strap length has potential to influence the risk of low back pain (LBP).

PRACTICAL APPLICATIONS

The findings suggest that fire services promote targeting physical training at firefighters' hip and knee regions. Test firefighters in this study were not advisable to adjust their shoulder strap at loose-fitting condition. The compatibility design of the trunk morphology and SCBA back-mounted frame was suggested for the management of LBP.

Investigation of health literacy status and related influencing factors in military health providers of Chinese People's liberation Army, a cross-sectional study

OBJECTIVE

The aim of this study was to investigate health literacy and analyze its influencing factors in military health providers of the Chinese People's Liberation Army (PLA Army).

METHODS

From November to December 2018, cluster sampling was used to select 1512 military health providers from the Army Medical University. Health literacy was measured by using the Chinese Citizen Health Literacy Questionnaire (HLQ) (2015 edition). Influencing factors that may affect health literacy were assessed using the chi-square test and multivariate logistic regression models.

RESULTS

The knowledge rate of health literacy was relatively low (21.6%). The knowledge rate of health-related skills (HRS, 18.7%) was the lowest of the three aspects of health literacy, and the knowledge rate of chronic diseases (CD, 19.6%) was the lowest of the six dimensions of health literacy. Participants who were older, were female, were of Han ethnicity, were the only child in their families, came from urban areas, never used tobacco, and had higher household income were likely to have higher health literacy.

CONCLUSION

The health literacy levels of military health providers of the PLA Army are relatively low. Further research and health education are necessary to improve health literacy.

Exploring links between Chinese military recruits' psychological stress and coping style from the person-environment fit perspective: The chain mediating effect of self-efficacy and social support

The choice of coping style of recruits under psychological stress in the process of military task execution has been an important topic in the promotion of military operations and cohesion of military forces. Taking a positive coping style under psychological stress can help recruits overcome the negative effects of stress and improve military morale and group combat effectiveness. Although soldiers' psychological stress in the process of military mission execution having an impact on coping style has been studied by a large body of literature, very little literature has focused on the mechanism of self-efficacy and social support between recruits' psychological stress and coping style from the person-environment fit perspective. Therefore, this study was conducted to analyze the impact of recruits' psychological stress on coping style through a chain mediation model and to discuss the role of self-efficacy and social support in this relationship. Two waves of survey data were utilized to test the research hypotheses on a sample of 1028 Chinese recruits performing military tasks. The results indicated that recruits' psychological stress negatively impacted positive coping styles and positively correlated with negative ones. In addition, self-efficacy and social support mediated the relationship between psychological stress and positive coping style, and self-efficacy mediated the relationship between psychological stress and negative coping style. More importantly, self-efficacy and social support play the chain mediating effect between psychological stress and positive coping style.

Military training-related abdominal injuries and diseases: Common types, prevention and treatment

Military training is intense, difficult and often dangerous, so all kinds of injuries or diseases frequently occur during training. Most of the previous studies and reviews on military training-related injuries focused on musculoskeletal system, whereas there are no reviews of abdominal injuries and diseases. Although the incidence of military training-related abdominal injuries and diseases is relatively low, the patients' condition is often critical especially in the presence of abdominal organ injury, leading to multi-organ dysfunction syndrome and even death. This paper elaborates on common types of military training-related abdominal injuries and diseases as well as the prevention and treatment measures, which provides some basis for scientific and reasonable training and improvement of medical security.

Reliability evaluation of functional movement screen for prevention of military training injury: A prospective study in China

OBJECTIVES

This study aimed to evaluate the effectiveness and feasibility of functional movement screen (FMS) evaluation system and individualized intervention measures in preventing military training injuries.

METHODS

A total of 420 recruits from a unit of the People's Liberation Army of China were included as the research object. According to random grouping method, they were divided into observation group (Group A) and control group (Group B), with 210 patients in each group. Before recruit training, individual FMS was performed, and functional correction training was performed in the observation group according to the test scores, while no intervention measures were applied in the control group. After 3 months of training, the tests were repeated. Age, body mass index (BMI), and incidence of military training injuries were recorded during the training period.

RESULTS

There was no statistical difference between the two groups in age, BMI, FMS score before the training (P > .05). After receiving functional correction training, the FMS score of the Group A was higher than that of the Group B, and the difference was statistically significant (P < .05). The incidence of military training injury in Group A and Group B was 20.95% and 44.02%, respectively (P < .05), and the difference was statistically significant.

CONCLUSION

The evaluation system of FMS and individualized intervention measures are feasible and effective in predicting and reducing the occurrence of military training injuries.