Physical and Performance Characteristics Related to Unintentional Musculoskeletal Injury in Special Forces Operators: A Prospective Analysis

Body composition as a marker of performance and health in military personnel

Introduction

Body composition standards are set to ensure operational readiness in active-duty military personnel. To meet body composition standards, some individuals, however, may engage in unhealthy weight control behaviors (i.e., weight cycling and disordered eating). The objectives of this review are to: (1) evaluate the evidence regarding body composition and the associations to physical and military specific performance; (2) discuss body composition and potential health consequences; and (3) examine the evidence of weight cycling and disordered eating behaviors in military personnel for weight control.

Methods

A systematic search to identify peer-reviewed research articles was conducted in PubMed on 2/20/2023 using Medical Subject Headings (MeSH) including but not limited to "Military Personnel", "Tactical Athlete", "Weight Loss", "Body Composition", and "Weight Cycling".

Results

A total of 225 research articles were identified. The list was narrowed down to articles from the last 20 years (2003-2023) in military personnel. Only studies in which percent body fat was directly measured were included resulting in 17 research articles for this review.

Discussion

Evidence-based research is limited on the relationship between body composition and operational readiness. Weight cycling and disordered eating behaviors also has been reported for weight control, yet additional research is needed. Specifically, future research should focus on female service members, racial and ethnic differences, age, and postpartum status and include other service branches (i.e., Air Force and Navy). A comprehensive survey on weight cycling, disordered eating, and weight management would be valuable to determine the prevalence and extent of this issue. This information along with performance data would guide policy makers on the relevance and appropriateness of existing body composition standards.

Risk factors for injuries along an infantry commanders course

To determine the influence of prevention programme on somatosensory ability in combat soldiers during 14-weeks of an infantry commanders course, two cohorts were recruited (INT-group, n = 196; CONT-group, n = 169). Soldiers were tested pre-and post-course for anthropometric measurements, proprioceptive ability, dynamic postural balance, and filled CAIT questionnaire. The INT-group performed injury prevention exercises and the CONT-group continued with their routine physical fitness lessons. All musculoskeletal injuries were recorded along the course. In the CONT-group 24.2% and in the INT-group 19.9% suffered injury during the course. The rates of injuries were not significantly different between groups (χ2(1) = .677 p = .411). Previous injury (OR = 3.349, 95% CI = 1.283-8.740), pre-course BMI (OR = 1.216, 95% CI = 1.064-1.389), and pre-course proprioception ability (OR = .870, 95% CI = .810-.935) were factors associated with injury in the CONT-group. Pre-course proprioception ability (OR = .769, 95% CI = .699-.846) and pre-course CAIT score (OR = .087, 95% CI = .027-.276) were factors in the INT-group. Soldiers who received injury prevention exercises had a similar prevalence of total musculoskeletal injuries as those who did not receive these exercises. Risk factors for injuries were different in the two groups.

Do the Lower Body Strength Assessment Tests in the Spanish Navy Really Measure What They Purport to Measure?

The main objective of this research was to analyse the efficacy of lower body strength assessment tests in the Armed Forces Physical Assessment System. Secondly, it was to determine what relationship exists between the physical evaluation system of the Spanish Armed forces and standardized evaluation protocols (Gold standard). A total of 905 students enrolled in the military/civil bachelor’s degree (813 male and 92 female) participated in this study. The influence of the sex of the participants was studied through the student’s t-test for independent data, and the degree of association between variables was defined by Pearson’s correlation coefficient. The results present moderate correlations (r = 0.67, r = 0.66; p < 0.001) between the vertical jump test used by the Army and the power or elastic force tests commonly used in practice and in research. The results obtained reflect a moderate relationship between the gold standard tests and the tests used by the Army, which suggests that the tests currently used to assess lower body strength should be adapted to more objective measurement tools which would allow a better comparison between samples from different armed forces.

Risk factors for musculoskeletal injuries in the military: a qualitative systematic review of the literature from the past two decades and a new prioritizing injury model

BACKGROUND

Musculoskeletal injuries (MSkIs) are a leading cause of health care utilization, as well as limited duty and disability in the US military and other armed forces. MSkIs affect members of the military during initial training, operational training, and deployment and have a direct negative impact on overall troop readiness. Currently, a systematic overview of all risk factors for MSkIs in the military is not available.

METHODS

A systematic literature search was carried out using the PubMed, Ovid/Medline, and Web of Science databases from January 1, 2000 to September 10, 2019. Additionally, a reference list scan was performed (using the "snowball method"). Thereafter, an international, multidisciplinary expert panel scored the level of evidence per risk factor, and a classification of modifiable/non-modifiable was made.

RESULTS

In total, 176 original papers and 3 meta-analyses were included in the review. A list of 57 reported potential risk factors was formed. For 21 risk factors, the level of evidence was considered moderate or strong. Based on this literature review and an in-depth analysis, the expert panel developed a model to display the most relevant risk factors identified, introducing the idea of the "order of importance" and including concepts that are modifiable/non-modifiable, as well as extrinsic/intrinsic risk factors.

CONCLUSIONS

This is the qualitative systematic review of studies on risk factors for MSkIs in the military that has attempted to be all-inclusive. A total of 57 different potential risk factors were identified, and a new, prioritizing injury model was developed. This model may help us to understand risk factors that can be addressed, and in which order they should be prioritized when planning intervention strategies within military groups.

Comparisons and Intercorrelations of Physical Performance Variables of Operational Preparedness in Special Operations Forces

INTRODUCTION

Marine Forces Special Operations Command (MARSOC) deploys teams of operators (OP) and enablers (EN) to accomplish special operations missions. OP and EN are required to train and deploy together to accomplish these missions; however, they have different training and selection pipelines. Advanced strength and conditioning training strategies are applied to both OP and EN to enhance physical preparedness; however, it is unclear how the selection pipeline of these two personnel types affects overall physical preparedness and the relationships between performance variables. The purpose of this study is to gain a greater understanding of the relationships of a wide array of physical preparedness variables in OP and EN in an effort to streamline testing and training strategies.

MATERIALS AND METHODS

For this study, 155 male (82 OP, 73 EN) MARSOC personnel (age: 29.5 ± 4.9 years, mass: 87.9 ± 11.1 kg, height: 1.79 ± 0.07 m) completed a physical preparedness assessment that included a DEXA assessment of body composition (BF%), 27.4 m sprint (30 yd), countermovement jump (VJ), 5-10-5 pro-agility (Agility), medicine ball toss (UBP), isometric mid-thigh pull (IMTP), and a 30 second (AnC) and 5 minute (AC) non-motorized treadmill run. Independent samples t tests, Mann-Whitney U tests, and Spearman's Rank correlations were used to compare variables between OP and EN.

RESULTS

OP demonstrated greater VJ, UBP, IMTP, AnC, and AC (P < 0.05); and significantly lower BF% and agility time (P < 0.05). Measurements of mass, height, body mass index, and 30 yd were not significantly different (P > 0.05). Weak to moderate correlations were seen between anthropometric and performance variables. OP and EN demonstrated similar correlations for most performance and anthropometric variables.

CONCLUSIONS

These results suggest that MARSOC OP demonstrate better physical preparedness over EN, while similar trends are observed between performance variables. Tests with moderate to high correlations may be removed from the protocol to account for testing time constraints. Height, weight, and BF% variables are poorly correlated with performance, particularly in OP, questioning their value in physical performance assessments in this population.

Association Between Markerless Motion Capture Screenings and Musculoskeletal Injury Risk for Military Trainees: A Large Cohort and Reliability Study

Background:

Markerless motion capture (MMC) systems used to screen for musculoskeletal injury (MSKI) risk have become popular in military and collegiate athletic settings. However, little is known regarding the test-retest reliability or, more importantly, the ability of these systems to accurately identify individuals at risk for MSKI.

Purpose:

To determine the association between scores from a proprietary MMC movement screen test and the likelihood of suffering a subsequent MSKI and establish the test-retest reliability of the MMC system used.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Trainees for the Air Force Special Warfare program underwent MMC screenings immediately before entering the 8-week training course. MSKI data were extracted from a database for the surveillance period for each trainee. Logistic regression analyses were performed to identify associations between baseline MMC scores and the likelihood of suffering any MSKI or, specifically, a lower extremity MSKI. The test-retest portion of the study collected MMC scores from 10 separate participants performing 4 trials of the standard test procedures. Reliability was assessed using intraclass correlation coefficients by a single rater.

Results:

Overall, 1570 trainees, of whom 800 (51%) suffered an MSKI, were included in the analysis. MMC scores poorly predicted the likelihood of any or a lower extremity MSKI (odds ratio, 1.01-1.02). Further, receiver operating characteristic curve analyses demonstrated poor sensitivity and specificity for prediction of MSKI with MMC scores (area under the curve = 0.53). Finally, intraclass correlation coefficients from the test-retest analysis of MMC scores ranged from 0.157 to 0.602.

Conclusion:

This MMC system displayed poor to moderate test-retest reliability and did not demonstrate the ability to discriminate between individuals who were and were not likely to suffer an MSKI.

Injury Prevention Exercises for Reduced Incidence of Injuries in Combat Soldiers

ABSTRACT

Steinberg, N, Bar-Sela, S, Moran, U, Pantanowitz, M, Waddington, G, Adams, R, Band, SS, and Funk, S. Injury prevention exercises for reduced incidence of injuries in combat soldiers. J Strength Cond Res XX(X): 000-000, 2021-The aim of this study was to determine the influence of an "all-cause injury" prevention program, focused on static-to-dynamic transitions, on injury prevalence in a military commanders course. Two cohorts of male infantry commanders were recruited (intervention [INT group], n = 196 and controls [CO group], n = 169) and tracked by a physiotherapist, who recorded any injuries that occurred during the 14-week course. Soldiers were tested precourse, midcourse, and postcourse for anthropometrics, proprioception ability, and dynamic postural balance (DPB). The INT group performed injury prevention exercises for 5 minutes, 3 times a week, and the CO group continued with their routine physical fitness sessions. The prevalence of injuries reported to the physiotherapist during the course was significantly lower for the INT group compared with the CO group (14.8 and 34.3%, respectively, p < 0.001). Similarly, rates of injury in the INT group were significantly lower than in the CO group (p < 0.001; hazard = 2.53, 95% confidence interval = 1.62-3.95). Precourse proprioception ability was significantly lower in those that became injured during the commanders course, irrespective of the group. Likewise, for DPB parameters, the injured subjects in both groups had significantly lower precourse scores than the noninjured subjects. From pretesting to midtesting, the injured soldiers in the INT group improved their ability up to the level of the noninjured subjects. A reduced prevalence of injuries was found for soldiers who completed the injury prevention program. Because the subjects soldiers injured on the course had reduced somatosensory abilities at the outset, and as these abilities can be improved by static-to-dynamic exercises, identifying at-risk soldiers and providing them with appropriate strategies for improvement beforehand is indicated.

Much work remains to reach consensus on musculoskeletal injury risk in military service members: A systematic review with meta-analysis

Musculoskeletal injuries are the most common reason military service members cannot perform their military duties. Not only are they costly and associated with long-term disability, often long after completion of military service, but injuries also adversely affect the military readiness of a nation. This can be seen as a threat to national security and part of the impetus behind many efforts to better understand, predict, and mitigate injury risk in the military. A systematic review of the literature published between 1995 and October 31, 2020 was conducted to identify significant risk factors of musculoskeletal injury in military populations across the world. 74 out of 170 eligible studies addressed comprehensive injuries, providing 994 unique risk factors. 46 of these studies provided data that could be included in a meta-analysis, which was possible for 15 predictor variables. Seven predictors were significant in meta-analysis: female sex(RR=1.46;95CI 1.30,1.64), high body mass index(RR=1.36;95CI 1.21,1.53), functional movement screen pain (RR=1.70;95CI 1.55,1.87) or scores ≤ 14(RR=1.42 95CI 1.29,1.56), prior injury(RR=1.54;95CI 1.32,1.80), slower running performance(RR=1.33;95CI 1.18,1.51), and poorer push-up performance(RR=1.15;95CI 1.04,1.27). Low BMI, height, weight, smoking, physical activity scores, and sit-up and jump performance were not significant risk factors in the meta-analysis. Most studies had a high risk of bias. Lack of raw data and large heterogeneity in definitions of predictors and injury outcomes limited comparison across many studies.Highlights Female sex, high body mass index, pain with functional movement screen or a score of ≤ 14, prior injury, slower running performance and poorer push-up performance were all significant predictors of musculoskeletal injury.Low body mass index, height, weight, smoking, physical activity scores, and sit-up and jump performance were not significant predictors of musculoskeletal injury.Many other predictors were present only in single studies, but large heterogeneity in definitions of both outcomes and predictors limited comparison across studies.Overall, studies assessing risk factors to predict musculoskeletal injuries in the military were at high risk for bias, especially in regards to statistical approaches.

Isokinetic Trunk Strength in Acute Low Back Pain Patients Compared to Healthy Subjects: A Systematic Review

BACKGROUND

The purpose of this systematic review was to: (I) determine the quality of evidence from studies assessing trunk isokinetic strength in subjects with acute low back pain (ALBP) compared to healthy subjects and (II) establish reference values of isokinetic trunk strength in subjects with ALBP.

METHODOLOGY

Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) statements were followed using keywords associated with trunk, strength and low back pain. Four databases were used: PubMed, Web of Science, Scopus and SPORTDiscus. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS).

RESULTS

A total of 1604 articles were retrieved, four included in this review. All were evaluated as high risk of bias (Rob). Due to the high Rob and the diversity of protocols, instruments and variables used, it was not possible to determine reference values for subjects with ALBP, we can only establish a range of flexion peak torque (PT) between 175.1 and 89.7 Nm at 60°/s and between 185 and 81.5 Nm at 120°/s, and for extension PT between 240.0 and 91.5 Nm at 60°/s and between 217.5 and 69.2 Nm at 120°/s in subjects with ALBP.

CONCLUSIONS

Due to the low quality of the evidence and the diversity of protocols used when measuring trunk isokinetic strength, it is necessary to carry out new high-quality research to establish reference values of trunk strength in subjects with ALBP.

Factors associated with musculoskeletal injuries in an infantry commanders course

OBJECTIVES

To evaluate the prevalence of injuries among young combat soldiers as assessed and reported by the military physicians, and to investigate whether parameters such as anthropometric measures, postural balance, proprioceptive ability, and chronic ankle instability are related to injuries during and following an infantry commanders course.

METHODS

In this cross-sectional study, 165 soldiers were tested for anthropometric measurements, proprioceptive ability, and dynamic postural balance (DPB), as well as for their responses to an ankle stability questionnaire (CAIT), on three occasions: pre-course, middle-course, and end-course testing. All musculoskeletal injuries were assessed and recorded in the digital medical file of each participant by specialist military physicians before and during/following the course.

RESULTS

Ninety-eight soldiers (59.4%) were injured before the course. Forty soldiers (24.2%) incurred an injury during/following the course (with 33 out of the 40 [82.5%] soldiers that were injured during/following the course having also been injured before the course). Sixty soldiers had no injury before/during/following the course. A survival curve showed that half of the soldiers who were injured during/following the course (20 soldiers) were recorded as injured in the first half of the course (during the first 46 days of the 92-day course). Logistic regression showed that the pre-course parameters that were significant among injured soldiers compared with the non-injured soldiers were: low CAIT results (OR = 2.736, 95% CI = 1.178-6.354), high BMI (OR = 1.234, 95% CI = 1.082-1.406) and reduced proprioceptive ability (OR =.858, 95% CI =.797-.924).

CONCLUSION

With a high prevalence of soldiers injured during and following a commanders course, a somatosensory intervention program should be generalized into the practical daily preparation and training routines of the soldiers for improving somatosensory abilities, optimizing military physical readiness, and for preventing future musculoskeletal injuries.

Musculoskeletal injury in military Special Operations Forces: a systematic review

INTRODUCTION

Special Operations Forces conduct military activities using specialised and unconventional techniques that offer a unique and complementary capability to conventional forces. These activities expose Special Operations Forces personnel to different injury risks in comparison with personnel in the conventional forces. Consequently, different injury patterns are expected in this population. The purpose of this research is to establish high-level evidence informing what is known about musculoskeletal injury epidemiology in Special Operations Forces.

METHODS

A systematic review was conducted using three online databases to identify original studies reporting musculoskeletal injury data in Special Operations Forces. A critical appraisal tool was applied to all included studies. Descriptive data were extracted for demographics, study design details and injuries (eg, injury frequency, injury type, body part injured, activity, mechanism, severity). Results were narratively synthesised.

RESULTS

Twenty-one studies were included. Trainees conducting qualification training had the highest injury frequency, up to 68% injured in a training period. The ankle, knee and lumbar spine were the most common body parts affected. Parachuting caused the most severe injuries. Physical training was the most common activity causing injury, accounting for up to 80% of injuries. Running and lifting were common injury mechanisms. Injury causation information was frequently not reported. Partially validated surveillance methods limited many studies.

CONCLUSIONS

Injuries are prevalent in Special Operation Forces. Future research should prioritise identifying injury causation information that supports prevention. Focus on improving surveillance methods to enhance the accuracy and comparison of results across cohorts is also recommended.

Incidence of injuries and factors related to injuries in combat soldiers

Introduction

Musculoskeletal injuries to the lower extremities are major factors contributing to drop out from military tasks. The aim of the present study was to determine the incidence of musculoskeletal injuries and the parameters that differentiate between the soldiers who incurred these injuries and those who did not along 14 weeks of an infantry commanders course.

Methods

One-hundred and sixty-eight participants were recruited from an infantry commanders course. The soldiers were tested before (pre), in the middle (middle) and at the end (last) of the course for anthropometric measurements, proprioceptive ability and dynamic postural balance (DPB), and filled out an ankle stability questionnaire (Cumberland Ankle Instability Tool (CAIT). A physiotherapist followed and recorded all musculoskeletal injuries incurred by the participants during the course.

Results

Fifty-eight participants out of the 168 (34.5%) reported some pain/injury. Time effects were found for body mass index, DPB asymmetry, DPB in posterior-medial (P-M) direction and proprioception ability. Injury effects were found for DPB asymmetry, DPB in P-M direction, CAIT and proprioception ability. An interaction was found for proprioception ability. The Cox regression showed that the variables that are mostly effecting injuries were pretesting proprioception ability, DPB asymmetry and CAIT.

Conclusions

More than one out of three participants incurred musculoskeletal injuries, with deficits in proprioception ability, DPB and ankle stability in pretesting as major factors contributing to injuries. Further studies should look at the effect of specific exercises such as proprioception, DPB and ankle stability exercises for prevention and treatment of musculoskeletal injuries among combat soldiers.

The Warrior Model for Human Performance Optimization

Special Operations Combat Personnel (SOCP) face significant challenges and occupational demands that put them at significant risk for musculoskeletal injury. Musculoskeletal injury leads to lost-duty days, medical disqualification, and compromises operational readiness and mission success. Optimizing human performance and developing injury prevention strategies can position SOCP for success, but human performance optimization is a complex process that demands the integration of multiple disciplines to address a broad range of capabilities necessary for this success. The Warrior Model for Human Performance Optimization outlines a step-by-step approach to human performance optimization embedded within a scientific, evidenced-based approach to injury prevention and performance optimization that includes a step to ensure specificity of training and interventions. This evidence-based approach can insure that SOCP capabilities match the demands of occupation enabling them to successfully execute their occupation tasks without risk of injury. While the focus of this review is on military personnel, the same principles have application to nonmilitary high-performance athletes.