What Risk Factors Are Associated With Musculoskeletal Injury in US Army Rangers? A Prospective Prognostic Study

Movement Clearing Screens for Military Service Member Musculoskeletal Injury Risk Identification

CONTEXT

Pain during movement screens is a risk factor for musculoskeletal injury (MSKI). Movement screens often require specialized or clinical expertise and large amounts of time to administer.

OBJECTIVE

Evaluate if self-reported pain (1) with movement clearing screens is a risk factor for any MSKI, (2) with movement clearing screens is a risk factor for body region-specific MSKIs, and (3) with a greater number of movement clearing screens progressively increases MSKI risk.

DESIGN

Retrospective cohort study.

SETTING

Field-based.

PATIENTS OR OTHER PARTICIPANTS

Military service members (n = 4222).

MAIN OUTCOME MEASURE(S)

Active-duty service members self-reported pain during movement clearing screens (Shoulder Clearing, Spinal Extension, Squat-Jump-Land). Musculoskeletal injury data were abstracted up to 180 days post-screening. A traffic light model grouped service members if they self-reported pain during 0 (Green), 1 (Amber), 2 (Red), or 3 (Black) movement clearing screens. Cox proportional hazards models adjusted for age, gender, body mass index, and prior MSKI determined the relationships between pain during movement clearing screens with any and body region-specific MSKIs.

RESULTS

Service members self-reporting pain during the Shoulder Clearing (adjusted hazard ratio and 95% confidence interval [HRadj (95% CI)] = 1.58 [1.37, 1.82]), Spinal Extension (HRadj = 1.48 [1.28, 1.87]), or Squat-Jump-Land (HRadj = 2.04 [1.79, 2.32]) tests were more likely to experience any MSKI than service members reporting no pain. Service members with pain during the Shoulder Clearing (HRadj = 3.28 [2.57, 4.19]), Spinal Extension (HRadj = 2.80 [2.26, 3.49]), or Squat-Jump-Land (HRadj = 2.07 [1.76, 2.43]) tests were more likely to experience an upper extremity, spine, back, and torso, or lower extremity MSKI, respectively, than service members reporting no pain. The Amber (HRadj = 1.69 [1.48, 1.93]), Red (HRadj = 2.07 [1.73, 2.48]), and Black (HRadj = 2.31 [1.81, 2.95]) cohorts were more likely to experience an MSKI than the Green cohort.

CONCLUSIONS

Self-report movement clearing screens in combination with a traffic light model provide clinician- and nonclinician-friendly expedient means to identify service members at MSKI risk.

Reliability and Validity of the Star Excursion Balance Test for Evaluating Dynamic Balance of Upper Extremities

BACKGROUND

Upper extremity (UE) dynamic balance is a significant physical fitness ability, which includes high-level neuromuscular proprioception, joint mobility, force, and coordination. The evaluation methods of UE dynamic balance are insufficient and lack experimental support. The Star Excursion Balance Test (SEBT) is a reliable assessment of dynamic balance and injury risk of the lower extremity.

HYPOTHESIS

The UE-SEBT is a reliable and reproducible approach for evaluating dynamic balance of UEs.

STUDY DESIGN

Observational study.

LEVEL OF EVIDENCE

Level 4.

METHODS

This cross-sectional study recruited 65 healthy adults. All participants were required to complete UE-SEBT, UE Y-balance test (UE-YBT), maximal voluntary isometric contraction (MVIC) of UE, closed kinetic chain UE stability test (CKCUEST), trunk flexor endurance test (TFET), trunk extensor endurance test (TEET), and lateral trunk endurance test (LTET). Intra- and inter-rater reliability and the correlation of UE-SEBT with other outcomes were measured.

RESULTS

Among the participants, the intra- and interoperator reliability of UE-SEBT in all directions and composite score achieved a moderate-to-excellent (intraclass correlation coefficients [ICC], 0.729-0.946) reliability. For validity, the UE-SEBT had a moderate to very strong correlation with UE-YBT (r = 0.315-0.755, P < 0.01) and a strong correlation with CKCUEST (r = 0.4-0.67, P < 0.01). Furthermore, the UE-SEBT performance showed weak-to-strong correlations with MVIC (r = 0.26-0.43, P < 0.05). UE-SEBT was also correlated with LTET, TEET, and TFET to varying degrees.

CONCLUSION

UE-SEBT has good reliability and validity to assess UE dynamic balance compared with other tests.

CLINICAL RELEVANCE

UE-SEBT can be used as a clinical assessment method to evaluate UE dynamic balance and injury prevention.

Gait asymmetry persists following unilateral and bilateral total ankle arthroplasty

Total ankle arthroplasty (TAA) improves gait symmetry in patients with unilateral end-stage ankle arthritis but has not been studied in patients undergoing bilateral TAA (B-TAA), and few studies compare TAA patients to control subjects. The purpose of this study was to compare gait symmetry in U-TAA and B-TAA patients and healthy controls. Using prospective databases, 19 unilateral and 19 bilateral ankle arthritis patients undergoing TAA were matched to 19 control subjects by age, sex, and BMI. The Normalized Symmetry Index (NSI) was determined for joint mechanics and ground reaction forces (GRF) during walking trials at a single visit for controls and preoperatively and 1 to 2 years postoperatively for TAA patients. Data was analyzed using linear mixed-effects models to determine differences among time points and cohorts at a significance of α = 0.05. Following surgery, B-TAA and U-TAA experienced improved peak plantarflexion moment symmetry (p = 0.017) but remained less symmetric than controls. B-TAA patients had more symmetry than U-TAA patients during peak weight acceptance GRF (p = 0.002), while U-TAA patients had greater peak dorsiflexion symmetry than B-TAA patients. TAA patients demonstrated more asymmetry compared to control subjects for all outcome measures. There was no significant impact of TAA on gait symmetry for GRF or peak ankle angles, and neither U-TAA nor B-TAA was consistently associated with higher gait symmetry. These results indicate that TAA improves symmetry during peak plantarflexion moment, and that significant gait asymmetry persists for B-TAA and U-TAA patients compared to healthy participants.

Risk Factors for Musculoskeletal Health: A Review of the Literature and Clinical Application

Context

Musculoskeletal disorders (MSKD) are currently the leading contributor to disability worldwide. Unlike other prevalent and disabling healthcare conditions such as CVD, risk factors associated with MSKD are not commonly discussed or integrated into current medical practice, rehabilitation practice or wellness programs. The primary purpose of this review is to describe the known risk factors most closely associated with MSKD. The secondary purpose is to propose a clinical model to manage MSK health aimed at maximizing the healthy pursuit of a physically active and healthy lifestyle.

Evidence acquisition

In this review the most common MSKD risk factors, with a focus on those that can be easily screened in clinical practice are presented. The importance of understanding the magnitude and number of risk factors present as well as the multidimensional nature of MSKD risk is discussed.

Results

A total of 11 MSKD risk factors were identified. Most of the risk factors are modifiable, and the evidence associated with modifiability for the most prominent risk factors is reviewed.Researchers have found that often patients are discharged from care with several known MSKD risk factors. In such instances, local pain and dysfunction are managed well, but expanding our rehabilitation care to include comprehensive risk factor management would ultimately benefit the patient and reduce healthcare costs.

Conclusion

The most common MSKD risk factors are discussed and a clinical framework to individualize intervention is proposed. Addressing key risk factors within rehabilitation may be an important step to reduce the enormous and growing burden these disorders are having on society.

Level of Evidence

5.

Ankle sprains in male Israeli infantry soldiers during training: prevalence and risk factors

BACKGROUND

Given the high incidence and heavy burden of ankle sprains in recruits, large-scale, multifactorial investigations into potential risk factors are warranted. This study aimed to identify the incidence of ankle sprains and associated risk factors among new military recruits during their infantry training.

METHODS

The study included 365 infantry recruits (aged 18-21 years), who were inducted into service in March 2022. These recruits were monitored for ankle sprains throughout their basicy and advanced infantry training by a physiotherapist. Preinduction smoking habits, physical fitness preparation and recurrent ankle sprains were recorded. Anthropometric measures, lower-extremity functional movement, Achilles tendon structure, perceived ankle instability, and mechanical ankle instability were assessed at the onset of both training periods.

RESULTS

Ankle sprains were diagnosed in 109 trainees (29.9%) during both the basic and the advanced training periods. Preinduction recurrent ankle sprains were reported by 28.2% of the participants. The relative risk of a recruit with preinduction ankle sprains suffering a subsequent sprain during training was 1.66 (p=0.001). Logistic regression analysis indicated that reduced proprioception ability (OR=0.002), higher body mass index (OR=1.08), preinduction recurrent sprains (OR=1.95) and lack of physical fitness preparation (OR=3.12) were related to ankle sprains throughout the complete basic-and-advanced training period. Preinduction recurrent ankle sprains (OR=3.37) and reduced Achilles tendon quality (OR=1.30) were associated with ankle sprains during the advanced training period.

CONCLUSIONS

Lower-extremity functional movement, body mass index, preinduction recurrent sprains, physical preparation and reduced Achilles tendon quality were associated with the risk of ankle sprains during training. These findings could contribute to developing prevention and intervention programmes for reducing ankle sprains in military trainees.

The Association Between Grip Strength, Upper Body Power, and Limb Dominance in a Military Population

INTRODUCTION

Military service members rely on upper body strength and power to accomplish tasks such as carrying heavy weapons and gear, rappelling, combat grappling, and marksmanship. Early identification of the factors that lead to reduced upper body strength and power would enable leadership to predict and mitigate aspects that decrease military operational readiness and increase injury risk. The purpose of this study was to investigate the relationship between grip strength and upper body power in U.S. Infantry Marines. We hypothesized that dominant arm grip strength would show a strong positive correlation with upper body power and that the dominant arm would be more powerful than the non-dominant arm.

MATERIALS AND METHODS

A total of 120 U.S. Marines completed 3 maximum effort isometric grip strength trials with their dominant hand and 3 maximum effort ballistic pushups on a ForceDecks force plate system. Force plate data were used to estimate pushup height and peak power. Maximum grip strength, pushup height, and peak power across the 3 trials were used for analysis. Pearson's correlation was used to test for associations between peak power, pushup height, and grip strength. Paired t-tests were used to test for differences in peak power between the dominant and non-dominant arms.

RESULTS

A very weak correlation was found between grip strength and upper body power, but there was no relationship between grip strength and pushup height. Additionally, there were no significant differences in upper body power between the dominant and non-dominant arms.

CONCLUSIONS

The results of this study suggest that grip strength is not predictive of upper body power and cannot be used as a stand-alone measure of physical readiness in a military unit. These findings do not, however, degrade the potential of both measures to predict and inform health status and physical readiness. Future prospective research should be conducted to determine if either of these measures can be used as indicators of performance and/or injury susceptibility and if limb dominance plays a role in injury incidence within the upper extremity.

Modeling Risk for Lower Extremity Musculoskeletal Injury in U.S. Military Academy Cadet Basic Training

INTRODUCTION

Sport and tactical populations are often impacted by musculoskeletal injury. Many publications have highlighted that risk is correlated with multiple variables. There do not appear to be existing studies that have evaluated a predetermined combination of risk factors that provide a pragmatic model for application in tactical and/or sports settings.

PURPOSE

To develop and test the predictive capability of multivariable risk models of lower extremity musculoskeletal injury during cadet basic training at the U.S.Military Academy.

MATERIALS AND METHODS

Cadets from the class of 2022 served as the study population. Sex and injury history were collected by questionnaire. Body Mass Index (BMI) and aerobic fitness were calculated during testing in the first week of training. Movement screening was performed using the Landing Error Scoring System during week 1 and cadence was collected using an accelerometer worn throughout initial training. Kaplan-Meier survival curves estimated group differences in time to the first musculoskeletal injury during training. Cox regression was used to estimate hazard ratios (HRs) and Akaike Information Criterion (AIC) was used to compare model fit.

RESULTS

Cox modeling using HRs indicated that the following variables were associated with injury risk : Sex, history of injury, Landing Error Scoring System Score Category, and Physical Fitness Test (PT) Run Score. When controlling for sex and history of injury, amodel including aerobic fitness and BMI outperformed the model including movement screening risk and cadence (AIC: 1068.56 vs. 1074.11) and a model containing all variables that were significant in the univariable analysis was the most precise (AIC: 1063.68).

CONCLUSIONS

In addition to variables typically collected in this tactical setting (Injury History, BMI, and aerobic fitness), the inclusion of kinematic testing appears to enhance the precision of the risk identification model and will likely continue to be included in screening cadets at greater risk.

Why are we doing this Staff? Justification and implications of aerobic fitness testing in the military

BACKGROUND

Physical fitness is a key tenet of military organisations worldwide. Specifically, many consider aerobic fitness (AF) an essential physical attribute for ensuring optimal military performance and readiness. However, the intricate relationship between AF and various facets of military job performance necessitates comprehensive review to ascertain the appropriateness and effectiveness of its assessment.

OBJECTIVE

This narrative review aims to describe the relationship between AF and factors influencing individual military performance and readiness, and explores the implications of the enforcement of in-service, generic AF test standards in military populations.

METHODS

Databases (PubMed and Google Scholar) were searched for all relevant published peer-reviewed literature as at August 2023.

RESULTS

Inconsistent associations were found between AF and outcomes influencing individual military performance (physical capabilities, cognitive capabilities, presenteeism and productivity, resilience, and technical/tactical capabilities) and readiness (mental health and wellbeing and physical health). Consequently, the level of AF needed for acceptable or optimal military performance remains uncertain.

CONCLUSIONS

AF is a cornerstone of health and performance, yet linking generic AF test standards to job performance is complex, with multiple factors interacting to influence outcomes. From existing literatures, there does not appear to be a specific level of AF at, and/or above, which acceptable military performance is achieved. As such, the enforcement of and emphasis on in-service, pass/fail, generic AF test standards in military populations is questionable and requires thoughtful re-evaluation. Role/task-specific AF should be assessed through evidence-based PES and the use of generic AF tests limited to the monitoring and benchmarking of health-related fitness.

The Value of Strength as a Predictor of Musculoskeletal Injury in Canadian Armed Forces Basic Infantry Candidates

INTRODUCTION

Musculoskeletal injuries (MSKI) impact military organizations by threatening their operational readiness, warranting investigation into relevant factors to inform risk reduction strategies. While several self-reported and physical performance measures have been associated with MSKI among military personnel, few have been validated and none have been reported in Canadian basic infantry candidates. The purpose of this study was to investigate associations between self-reported and physical performance measures and MSKI, and determine their validity as predictors of MSKI, in Canadian basic infantry candidates.

METHODS

This was a planned secondary analysis of a study tracking MSKI at a basic infantry training facility in Ontario, Canada approved by Defence Research & Development Canada. Before the basic infantry training, consenting candidates completed a baseline testing session including self-reported questionnaires, measures of anthropometry, and physical performance previously associated with MSKI (ankle dorsiflexion test, Y-Balance Test, Isometric Mid-Thigh Pull, and the Fitness for Operational Requirements of CAF Employment (FORCE) evaluation). All MSKI reported by candidates were diagnosed by licensed healthcare providers. From a total sample of 129 candidates, 76% (n = 98) were used to determine any associations between baseline testing variables and MSKI and to develop a predictive model (Development Sample), while 24% (n = 33) were used to offer preliminary validation of the same predictive model (Validation Sample). The binary logistic regression and independent sample t-testing determined independent associations with MSKI in the Development Sample. All continuous variables and dichotomous variables previously associated with MSKI risk (Smoker Yes/No, previous history of MSKI, and physical inactivity) were entered into a backward stepwise logistic regression analysis to assess the predictive association with MSKI incidence in the Development Sample. The regression model was then applied to the Validation Sample.

RESULTS

A total of 35 MSKI were diagnosed by Health Services Centre staff. The majority of the MSKI were acute (63%), sustained to the hip, knee, and ankle (74%). The most common diagnoses were strains and sprains (71%). Uninjured participants performed significantly better on the Relative Isometric Mid-Thigh Pull, FORCE 20 mR, FORCE ILS, and FORCE Estimated VO2peak compared to injured participants. Logistic regression analysis showed that the only variable with significant independent association with diagnosed MSKI incidence was self-reported previous history of MSKI. However, the backward stepwise logistic regression analysis retained self-reported previous history of MSKI, FORCE SBD, FORCE Estimated VO2peak, and Isometric Mid-Thigh Pull Peak Force as predictors of MKSI. The logistic regression model including these variables could predict MSKI with an accuracy of 79% in the Development Sample and 67% in the Validation Sample.

CONCLUSION

This study provides preliminary support for the value of measures of absolute muscular strength and cardiorespiratory fitness as predictors of MSKI in Canadian basic infantry candidates. Given the associations between physical performance measures and MSKI, and their necessity during occupational tasks, it is recommended that Canadian basic infantry training facilities integrate resistance training with external loads to best prepare their candidates to meet their occupational demands and potentially minimize MSKI. Further investigations to confirm the predictive capacity of these variables in a larger sample across additional facilities are warranted.

Predictive Validity of Multifactorial Injury Risk Models and Associated Clinical Measures in the U.S. Population

Background: Popular movement-based injury risk screens were shown to lack predictive precision, leading to interest in multifactorial models. Furthermore, there is a lack of research regarding injury risk assessment for those currently or planning to be recreationally active. This study aims to provide injury risk insights by analyzing multifactorial injury risk models and associated clinical measures in the U.S. population. Methods: Data related to injury, inflammatory markers, physical functioning, body composition, physical activity, and other variables from 21,033 respondents were extracted from NHANES. Odds ratios for self-reported injury were calculated for single predictors and risk models. Case-control and principal component analyses (PCA) were conducted to elucidate confounders and identify risk factor clusters, respectively. Receiver operating characteristic analysis was used to test the precision of a risk factor cluster to identify pain points and functional difficulties. Results: Sociodemographic, individual, and lifestyle factors were strongly associated with higher odds of injury. Increases in fibrinogen and C-reactive protein were significantly associated with all risk groups. Membership to the high-risk group (age over 40, obesity, no muscle-strengthening activities, sedentary lifestyle, and low back pain) predicted at least one functional difficulty with 67.4% sensitivity and 87.2% specificity. In the injury group, bone turnover markers were higher, yet confounded by age, and there was a significantly higher prevalence of self-reported osteoporosis compared to the control. In males, low testosterone was associated with injury, and high estradiol was associated with pain and functional difficulties. In females, high follicle-stimulating hormone was associated with functional difficulties. PCA revealed four high-risk profiles, with markers and activities showing distinct loadings. Conclusions: A comprehensive approach to injury risk assessment should consider the nexus of aging, lifestyle, and chronic disease to enhance tailored injury prevention strategies, fostering safe and effective physical activity participation and reducing the burden of musculoskeletal disorders.

Can a Psychologic Profile Predict Successful Return to Full Duty After a Musculoskeletal Injury?

BACKGROUND

Psychologic variables have been shown to have a strong relationship with recovery from injury and return to work or sports. The extent to which psychologic variables predict successful return to work in military settings is unknown.

QUESTIONS/PURPOSES

In a population of active duty soldiers, (1) can a psychologic profile determine the risk of injury after return to full duty? (2) Do psychologic profiles differ between soldiers sustaining injuries in the spine (thoracic or lumbar) and those with injuries to the lower extremities?

METHODS

Psychologic variables were assessed in soldiers returning to full, unrestricted duty after a recent musculoskeletal injury. Most of these were noncombat injuries from work-related physical activity. Between February 2016 and September 2017, 480 service members who were cleared to return to duty after musculoskeletal injuries (excluding those with high-velocity collisions, pregnancy, or amputation) were enrolled in a study that tracked subsequent injuries over the following year. Of those, we considered individuals with complete 12-month follow-up data as potentially eligible for analysis. Based on that, approximately 2% (8 of 480) were excluded because they did not complete baseline surveys, approximately 2% (11 of 480) were separated from the military during the follow-up period and had incomplete injury data, 1% (3 of 480) were excluded for not serving in the Army branch of the military, and approximately 2% (8 of 480) were excluded because they were not cleared to return to full duty. This resulted in 450 soldiers analyzed. Individuals were 86% (385 of 450) men; 74% (331 of 450) had lower extremity injuries and 26% (119 of 450) had spinal injuries, including soft tissue aches and pains (for example, strains and sprains), fractures, and disc herniations. Time-loss injury within 1 year was the primary outcome. While creating and validating a new prediction model using only psychological variables, 19 variables were assessed for nonlinearity, further factor selection was performed through elastic net, and models were internally validated through 2000 bootstrap iterations. Performance was deciphered through calibration, discrimination (area under the curve [AUC]), R 2 , and calibration in the large. Calibration assesses predicted versus actual risk by plotting the x and y intersection of these values; the more similar predicted risk values are to actual ones, the closer the slope of the line formed by the intersection points of all subjects is to equaling "1" (optimal calibration). Likewise, perfect discrimination (predicted injured versus actual injured) presents as an AUC of 1. Perfect calibration in the large would equal 0 because it represents the average predicted risk versus the actual outcome rate. Sensitivity analyses stratified groups by prior injury region (thoracic or lumbar spine and lower extremity) as well as the severity of injury by days of limited duty (moderate [7-27 days] and severe [28 + days]).

RESULTS

A model comprising primarily psychologic variables including depression, anxiety, kinesiophobia, fear avoidance beliefs, and mood did not adequately determine the risk of subsequent injury. The derived logistic prediction model had 18 variables: R 2 = 0.03, calibration = 0.63 (95% confidence interval [CI] 0.30 to 0.97), AUC = 0.62 (95% CI 0.52 to 0.72), and calibration in the large = -0.17. Baseline psychologic profiles between body regions differed only for depression severity (mean difference 1 [95% CI 0 to 1]; p = 0.04), with greater mean scores for spine injuries than for lower extremity injuries. Performance was poor for those with prior spine injuries compared with those with lower extremity injuries (AUC 0.50 [95% CI 0.42 to 0.58] and 0.63 [95% CI 0.57 to 0.69], respectively) and moderate versus severe injury during the 1-year follow-up (AUC 0.61 [95% CI 0.51 to 0.71] versus 0.64 [95% CI 0.64 to 0.74], respectively).

CONCLUSION

The psychologically based model poorly predicted subsequent injury. This study does not minimize the value of assessing the psychologic profiles of injured athletes, but rather suggests that models looking to identify injury risk should consider a multifactorial approach that also includes other nonpsychologic factors such as injury history. Future studies should refine the most important psychologic constructs that can add the most value and precision to multifactorial models aimed at identifying the risk of injury.

LEVEL OF EVIDENCE

Level III, prognostic study.

Chronic Ankle Instability and Neuromuscular Performance in Prerecruitment Infantry Soldiers

CONTEXT

Ankle instability can describe various impairments, including perceived instability (PI), mechanical instability (MI), and recurrent sprains (RSs), alone or combined.

OBJECTIVE

To examine the prevalence of 8 ankle impairment subgroups and their effect on neuromuscular performance in prerecruitment combat soldiers.

DESIGN

Cross-sectional study.

SETTING

Military infantry basic training base.

PATIENTS OR OTHER PARTICIPANTS

A total of 364 infantry male combat soldiers entering basic training (aged 18-21 years).

MAIN OUTCOME MEASURE(S)

Participants were assessed for PI (via the Cumberland Ankle Instability Tool), MI (using the Anterior Drawer Test and Medial Talar Tilt Test), and RSs (based on history) of their dominant and nondominant legs. Injuries were categorized in 8 subgroups: PI, RSs, PI + RSs, MI, PI + MI, MI + RSs, PI + MI + RSs, and none. Participants were screened for neuromuscular performance (dynamic postural balance, proprioceptive ability, hopping agility, and triceps surae muscle strength) during the first week of military basic training.

RESULTS

For the dominant and nondominant legs, RSs were reported by 18.4% (n = 67) and 20.3% (n = 74) of the participants, respectively; PI was reported by 27.1% (n = 99) and 28.5% (n = 104) of the participants, respectively; and MI was seen in 9.9% (n = 36) and 8.5% (n = 31) of the participants, respectively. A 1-way analysis of variance showed differences in the mean proprioceptive ability scores (assessed using the Active Movement Extent Discrimination Apparatus) of all subgroups with impairments in both the dominant and nondominant legs (F = 6.943, η2 = 0.081, P < .001 and F = 7.871, η2 = 0.091, P < .001, respectively). Finally, differences were found in the mean muscle strength of subgroups with impairment in the nondominant leg (F = 4.884, η2 = 0.056, P = .001).

CONCLUSIONS

A high prevalence of ankle impairments was identified among participants who exhibited reduced abilities in most neuromuscular assessments compared with those who did not have impairments. Moreover, participants with 1 impairment (PI, MI, or RSs) exhibited different neuromuscular performance deficits than those with >1 impairment.

Predicting Subsequent Injury after Being Cleared to Return to Work from Initial Lumbar or Lower Extremity Injury

PURPOSE

The purpose of this study is to develop a model to predict re-injury after being cleared to return to full duty from an initial injury.

METHODS

This was a prediction model derivation cohort study. Military service members cleared for unrestricted full duty after sustaining a musculoskeletal injury were enrolled from three large military hospitals. Medical history, demographics, psychological profile, physical performance (Y-Balance Test™, Functional Movement Screen™, Selective Functional Movement Assessment, triple hop, closed chain ankle dorsiflexion, 2-mile run, 75% bodyweight carry time), and past injury history were assessed. Monthly text messages, medical records and limited duty databases were used to identify injuries resulting in time lost from work in the following year.

RESULTS

Four hundred fifty participants (65 females), ages 18 to 45 yr were analyzed. Fifteen variables were included in the final model. The area under the curve was 0.74 (95% confidence interval, 0.69-0.80), indicating good performance. The calibration score of the model was 1.05 (95% confidence interval, 0.80-1.30) indicating very good performance. With an injury incidence in our cohort of 38.0%, the treat all net benefit was 0.000, and the net benefit of our predictive model was 0.251. This means 25 additional soldiers out of every 100 were correctly identified as high risk for injury compared with not using a prediction model at all.

CONCLUSIONS

This multivariable model accurately predicted injury risk after returning for full duty and was better than not using a prediction model at all (an additional 25 of every 100 tactical athletes were correctly identified). This model provides guidance for proper decision making about when these individuals are not ready to return to full duty, with higher risk of a subsequent injury.

Role of ankle dorsiflexion in sports performance and injury risk: A narrative review

The objective of this literature review is to understand the role of ankle dorsiflexion range of motion in sports performance and the risk of injuries. The ankle harmonizes the interaction between the body and the supporting surface through adjusting to the supporting surface and handling forces to contribute effectually to different functional activities. Ankle dorsiflexion is an essential construct in many sport-specific skills. Ankle dorsiflexion is associated with activation of brain areas involved in movement preparation, sensory integration, motor planning/execution, balance, and visuomotor coordination. Ankle dorsiflexion was associated with enhanced activation of deep core and quadriceps muscles. Decreased ankle dorsiflexion is linked to compensations and altered kinetics and kinematics that can potentially affect sports performance and increase the chances of sustaining injuries. It is vindicated to consider more focus on ankle dorsiflexion range of motion in research studies, sports-related pre-season screening, clinical examination, injury rehabilitation, and return-to-sports judgment.

Assessing Injury Susceptibility at Marine Corps Recruit Depot, San Diego, California

ABSTRACT

Poh, PYS, Sessoms, PH, Haluch, KS, and Trone, DW. Assessing injury susceptibility at Marine Corps Recruit Depot, San Diego, California. J Strength Cond Res 37(7): 1530-1536, 2023-Marine Corps Recruit Depot (MCRD) recruits undergo demanding training. Musculoskeletal injury (MSKI) accounts for attrition and graduation delays. Functional tests, such as Functional Movement Screen (FMS), Y-Balance Test-Lower Quarter (YBT-LQ), and ankle dorsiflexion range of motion (AD-ROM), may identify individuals at greater MSKI risk. This study tested the hypothesis that functional assessments may inform injury prediction. Male recruits ( N = 407; mean ± SD : age, 20 ± 2 years) performed baseline functional tests. Marine Corps Recruit Depot staff tracked MSKI and graduation outcomes. The chi-square test of independence (individual FMS exercises) and Mann-Whitney U (FMS composite score) test examined the relationship between FMS and MSKI incidence. One-way analysis of variance compared YBT-LQ and AD-ROM with MSKI incidence. Twelve recruits (3%) incurred a lower extremity MSKI and were dropped. Of those 12, 9 had a delayed graduation, and 3 separated from enlistment. The level of significance was set at p < 0.10 to identify between-group differences (yes-MSKI vs. no-MSKI). Functional movement screen composite score ( p = 0.064), hurdle step ( p = 0.059), and trunk stability ( p = 0.001) were lower in yes-MSKI. Y-Balance Test-Lower Quarter anterior direction difference between legs ( p = 0.011) and AD-ROM right side ( p = 0.055) was greater in yes-MSKI. Odds ratios (OR) were calculated using cut-off scores, with strong odds of sustaining MSKI with FMS trunk stability score <2 (OR: 7.56, 95% confidence interval [CI]: [2.32, 24.61]) and YBT-LQ anterior difference >6.25 cm (OR: 6.38, 95% CI: [1.98, 20.55]). Recruits who incurred MSKI had scores that indicated lesser mobility and stability of the lower extremity, providing preliminary evidence that when assessed together, FMS, YBT-LQ, and AD-ROM, may have predictive value for identifying those at MSKI risk.

Musculoskeletal Injury Risk Stratification: A Traffic Light System for Military Service Members

Risk factor identification is a critical first step in informing musculoskeletal injury (MSKI) risk mitigation strategies. This investigation aimed to determine if a self-reported MSKI risk assessment can accurately identify military service members at greater MSKI risk and determine whether a traffic light model can differentiate service members' MSKI risks. A retrospective cohort study was conducted using existing self-reported MSKI risk assessment data and MSKI data from the Military Health System. A total of 2520 military service members (2219 males: age 23.49 ± 5.17 y, BMI 25.11 ± 2.94 kg/m²; and 301 females: age 24.23 ± 5.85 y, BMI 25.59 ± 3.20 kg/m², respectively) completed the MSKI risk assessment during in-processing. The risk assessment consisted of 16 self-report items regarding demographics, general health, physical fitness, and pain experienced during movement screens. These 16 data points were converted to 11 variables of interest. For each variable, service members were dichotomized as at risk or not at risk. Nine of the 11 variables were associated with a greater MSKI risk and were thus considered as risk factors for the traffic light model. Each traffic light model included three color codes (i.e., green, amber, and red) to designate risk (i.e., low, moderate, and high). Four traffic light models were generated to examine the risk and overall precision of different cut-off values for the amber and red categories. In all four models, service members categorized as amber [hazard ratio (HR) = 1.38-1.70] or red (HR = 2.67-5.82) were at a greater MSKI risk. The traffic light model may help prioritize service members who require individualized orthopedic care and MSKI risk mitigation plans.

Financial Impact of Embedded Injury-Prevention Experts in US Army Initial Entry Training

CONTEXT

The US Army embedded injury-prevention experts (IPEs), specifically athletic trainers and strength and conditioning coaches, into initial entry training (IET) to limit musculoskeletal (MSK) conditions and their negative consequences. However, little is known about the financial impact of IPEs.

OBJECTIVE

To assess whether IPEs were associated with fewer sunk training costs due to MSK-related early discharges from service.

DESIGN

Retrospective cohort study.

SETTING

Database of US Army soldiers' administrative, medical, and readiness records.

PATIENTS OR OTHER PARTICIPANTS

A total of 198 166 soldiers (age = 20.7 ± 3.2 years, body mass index = 24.4 ± 3.5 kg/m2) who began IET during 2014 to 2017.

MAIN OUTCOME MEASURE(S)

Early discharge from service was defined as occurring within 6 months of beginning IET. All IET sites employed IPEs from 2011 to 2017, except for 2 sites during April to November 2015. Soldiers who began IET at these 2 sites during these times were categorized as not having IPE exposure. All others were categorized as having IPE exposure. The unadjusted association between IPE access and MSK-related early discharge from service was assessed using logistic regression. Financial impact was assessed by quantifying differences in yearly sunk costs between groups with and those without IPE exposure and subtracting IPE hiring costs.

RESULTS

Among 14 094 soldiers without IPE exposure, 2.77% were discharged early for MSK-related reasons. Among 184 072 soldiers with IPE exposure, 1.01% were discharged. Exposure to IPEs was associated with reduced odds of MSK-related early discharge (odds ratio = 0.36, 95% CI = 0.32, 0.40, P < .001) and a decrease in yearly sunk training costs of $11.19 to $20.00 million.

CONCLUSIONS

Employing IPEs was associated with reduced sunk costs because of fewer soldiers being discharged from service early for MSK-related reasons. Evidence-based recommendations should be developed for guiding policy on the roles and responsibilities of IPEs in the military to reduce negative outcomes from MSK conditions and generate a positive return on investment.

Self-Movement Screening using the Symmio Application is Reliable and Valid for Identifying Musculoskeletal Risk Factors

Background

Musculoskeletal health problems are one of the greatest healthcare expenses in the United States but patient-driven screening procedures to detect risk factors do not exist.

Hypothesis/Purpose

The purpose was to establish the inter-rater reliability of the Symmio Self-Screen application in untrained individuals and to investigate its accuracy to detect MSK risk factors such as pain with movement, movement dysfunction, and decreased dynamic balance.

Study Design

Cross-Sectional.

Methods

Eighty (42 male, 38 female) healthy individuals mean age 26.5 ± 9.4 participated in the study. The inter-rater reliability of Symmio application was established by comparing self-screen scores from untrained subjects with the results simultaneously determined by a trained healthcare provider. Each subject was evaluated for pain with movement, movement dysfunction, and deficits in dynamic balance by two trained evaluators who were blinded to the Symmio results. The validity of Symmio was determined by comparing self-screen performance dichotomized as pass or fail with the reference standard of pain with movement, failure on the Functional Movement Screen™, and asymmetry on the Y Balance Test-Lower Quarter™ using three separate 2x2 contingency tables.

Results

The mean Cohen's kappa coefficient was 0.68 (95% CI, 0.47-0.87) and the absolute agreement was 89% between self-assessment of subjects and the observation of a trained healthcare provider. There were significant associations for the presence of pain with movement (p=0.003), movement dysfunction (p=0.001), and dynamic balance deficits (p=0.003) relative to poor Symmio performance. The accuracy of Symmio to identify pain with movement, movement dysfunction, and dynamic balance deficits were 0.74 (95% CI, 0.63-0.83), 0.73 (95% CI, 0.62-0.82), and 0.69 (95% CI, 0.57-0.79), respectively.

Conclusions

The Symmio Self-Screen application is a reliable and feasible screening tool that can be used to identify MSK risk factors.

Level of Evidence

Level 2.

The Utility of Myotonometry in Musculoskeletal Rehabilitation and Human Performance Programming

Myotonometry is a relatively novel method used to quantify the biomechanical and viscoelastic properties (stiffness, compliance, tone, elasticity, creep, and mechanical relaxation) of palpable musculotendinous structures with portable mechanical devices called myotonometers. Myotonometers obtain these measures by recording the magnitude of radial tissue deformation that occurs in response to the amount of force that is perpendicularly applied to the tissue through a device's probe. Myotonometric parameters such as stiffness and compliance have repeatedly demonstrated strong correlations with force production and muscle activation. Paradoxically, individual muscle stiffness measures have been associated with both superior athletic performance and a higher incidence of injury. This indicates optimal stiffness levels may promote athletic performance, whereas too much or too little may lead to an increased risk of injury. Authors of numerous studies suggested that myotonometry may assist practitioners in the development of performance and rehabilitation programs that improve athletic performance, mitigate injury risk, guide therapeutic interventions, and optimize return-to-activity decision-making. Thus, the purpose of our narrative review was to summarize the potential utility of myotonometry as a clinical tool that assists musculoskeletal clinicians with the diagnosis, rehabilitation, and prevention of athletic injuries.

Achilles Tendon and Patellar Tendon Structure in Combat Soldiers Following Prevention Exercises

INTRODUCTION

Military training that increases physical stress on musculoskeletal morphology also increases the risk of orthopedic injuries. Somatosensory prevention programs that reduce stress and improve functionality could be beneficial for better organization of tendon structure. The aim of this study was to investigate the impact of a somatosensory prevention exercise on the tendon structure (percentage of echo-type fibers; A-P and M-L diameters and cross-sectional area) of the Achilles tendon and patellar tendon among combat soldiers.

MATERIALS AND METHODS

These tendons of male Infantry soldiers aged 18-21 were screened before and after a 14-week training course. The intervention group, who performed preventative exercises, included 108 soldiers (BMI = 23.85 ± 2.76), while the control group, who participated in the same military course without these exercises, included 98 soldiers (BMI = 24.26 ± 4.03). Ultrasound scanning for tendon structure included percent of echo-type I-IV fibers, A-P diameter, M-L diameter, and cross-sectional area parameters.

RESULTS

Time by group interaction was found for echo-type I and II in both tendons. No significant differences were found between the two groups in the pretesting percentage of echo-type IV fibers of the Achilles tendon (P = .522), in echo-type III fibers of the Achilles tendon (P = .833), and echo-type IV fibers of the patellar tendon (P = .162). Greater pre-post differences in echo-type III and IV fibers were found in the control group compared with the intervention group for both the Achilles tendon (P = .021, P = .002) and the patellar tendon (P < .001, P < .001).

CONCLUSION

Increased damaged fibers (echo-type III and IV) of both tendons were found among the control group, yet not among soldiers who performed prevention exercises.

Pre-neuromusculoskeletal injury Risk factor Evaluation and Post-neuromusculoskeletal injury Assessment for Return-to-duty/activity Enhancement (PREPARE) in military service members: a prospective, observational study protocol

BACKGROUND

Non-battle related musculoskeletal injuries (MSKI) are one of the primary medical issues diminishing Service member medical readiness. The MSKI problem is challenging because it is difficult to assess all of the factors that increase MSKI risk and influence post-MSKI outcomes. Currently, there are no high-throughput, clinically-feasible, and comprehensive assessments to generate patient-centric data for informing pre- and post-MSKI risk assessment and mitigation strategies. The objective of the "Pre-neuromusculoskeletal injury Risk factor Evaluation and Post-neuromusculoskeletal injury Assessment for Return-to-duty/activity Enhancement (PREPARE)" study is to develop a comprehensive suite of clinical assessments to identify the patient-specific factors contributing to MSKI risks and undesired post-MSKI outcomes.

METHODS

This is a phased approach, multi-center prospective, observational study (ClinicalTrials.gov number: NCT05111925) to identify physical and psychosocial factors contributing to greater MSKI risk and undesired post-MSKI outcomes, and to identify and validate a minimal set of assessments to personalize risk mitigation and rehabilitation strategies. In Phase I, one cohort (n = 560) will identify the physical and psychosocial factors contributing to greater MSKI risks (single assessment), while a second cohort (n = 780) will identify the post-MSKI physical and psychosocial factors contributing to undesired post-MSKI outcomes (serial assessments at enrollment, 4 weeks post-enrollment, 12 weeks post-enrollment). All participants will complete comprehensive movement assessments captured via a semi-automated markerless motion capture system and instrumented walkway, joint range of motion assessments, psychosocial measures, and self-reported physical fitness performance and MSKI history. We will follow participants for 6 months. We will identify the minimum set of clinical assessments that provide requisite data to personalize MSKI risk mitigation and rehabilitation strategies, and in Phase II validate our optimized assessments in new cohorts.

DISCUSSION

The results of this investigation will provide clinically relevant data to efficiently inform MSKI risk mitigation and rehabilitation programs, thereby helping to advance medical care and retain Service members on active duty status.

TRIAL REGISTRATION

PREPARE was prospectively registered on ClinicalTrials.gov (NCT05111925) on 5 NOV 2021, prior to study commencement.

Achilles and patellar tendon structure following a prevention program in male combat soldiers

OBJECTIVES

The aims of the study were to compare the prevalence of soldiers with musculoskeletal symptoms between soldiers that participated in a prevention program (INT) and a control group (CONT); and, to assess whether 'high risk' for a symptom indicator [participants with patellar tendon (PT) echo-type III+IV >10% or Achilles tendon (AT) echo-type III >8.5%] applies when a prevention intervention is used.

METHODS

Soldiers from two consecutive infantry commanders courses (year 1-CONT, n = 165; year 2-INT, n = 196) were examined pre-course for AT and PT structure using ultrasound tissue characterization (UTC), and their musculoskeletal overuse symptoms were assessed and recorded by military physicians throughout the course. A prevention program was provided to the INT group (year 2) during the 14-week course.

RESULTS

No significant differences were found in the prevalence of soldiers with symptoms between the two groups [INT: 39 (19.9%), CONT: 40 (24.2%); p = .32]. Using the indicator at baseline, 20 soldiers (10.2%) were suggested to be at 'high risk.' Of those 20 soldiers, 17 actually had symptoms during the course (positive predictive value-85%). The prevalence of soldiers with a suggested 'high risk' according to our indicator who had no symptoms during the course was low (3/20, 15%). Twenty-two soldiers who had symptoms during the course had not been suggested to be at 'high risk' by our indicator.

CONCLUSION

Our intervention did not reduce the prevalence of soldiers with symptoms. Our 'high risk' pre-course, AT and PT structure indicator is valid and can be used as a screening tool to reduce the prevalence of symptoms in combat soldiers; with the caution that soldiers that were not identified by the indicator, might also have symptoms along the course.

Effects of Yoga Intervention on Functional Movement Patterns and Mindfulness in Collegiate Athletes: A Quasi-Experimental Study

High-quality movement patterns and high levels of mindfulness are thought to be beneficial in preventing sports injuries. Yoga is recommended in the field of athlete rehabilitation. This study investigated the effects of yoga intervention on functional movement patterns and mindfulness in collegiate athletes. It is a quasi-experimental study with a pre/post-test control design. The participants were divided into a yoga group and a control group. A Functional Movement Screen and the Mindful Attention Awareness Scale were used to assess participants' basic movement patterns and mindfulness before and after 12 weeks of yoga intervention (two classes per week, 90 min per class). The results show that the yoga group's FMS scores improved more compared to the control group [F(1,78) = 29.08, p < 0.001, ŋp² = 0.27], and that the scores for the deep squat (ŋp² = 0.4), shoulder mobility (ŋp² = 0.17), and trunk stability pushup (ŋp² = 0.36) improved substantially. The dysfunctional score ratio for deep squats (χ² = 18.57, p < 0.001), shoulder mobility (χ² = 26.90, p < 0.001), trunk stability pushup (χ² = 17.07, p < 0.001), and rotatory stability (χ²= 38.29, p <0.001) decreased significantly compared with the control group, but there was no significant improvement in asymmetric movement patterns (χ² = 0.75, p = 0.39). The mindfulness scores in the yoga group significantly exceeded those of the control group [F(1,78) = 13.56, p < 0.001, ŋp² = 0.15]. These results suggest that yoga intervention can improve functional movement patterns and mindfulness levels, but further evidence is needed to determine whether yoga could positively influence sports injuries.

Predictive models for musculoskeletal injury risk: why statistical approach makes all the difference

OBJECTIVE

Compare performance between an injury prediction model categorising predictors and one that did not and compare a selection of predictors based on univariate significance versus assessing non-linear relationships.

METHODS

Validation and replication of a previously developed injury prediction model in a cohort of 1466 service members followed for 1 year after physical performance, medical history and sociodemographic variables were collected. The original model dichotomised 11 predictors. The second model (M2) kept predictors continuous but assumed linearity and the third model (M3) conducted non-linear transformations. The fourth model (M4) chose predictors the proper way (clinical reasoning and supporting evidence). Model performance was assessed with R², calibration in the large, calibration slope and discrimination. Decision curve analyses were performed with risk thresholds from 0.25 to 0.50.

RESULTS

478 personnel sustained an injury. The original model demonstrated poorer R² (original:0.07; M2:0.63; M3:0.64; M4:0.08), calibration in the large (original:-0.11 (95% CI -0.22 to 0.00); M2: -0.02 (95% CI -0.17 to 0.13); M3:0.03 (95% CI -0.13 to 0.19); M4: -0.13 (95% CI -0.25 to -0.01)), calibration slope (original:0.84 (95% CI 0.61 to 1.07); M2:0.97 (95% CI 0.86 to 1.08); M3:0.90 (95% CI 0.75 to 1.05); M4: 081 (95% CI 0.59 to 1.03) and discrimination (original:0.63 (95% CI 0.60 to 0.66); M2:0.90 (95% CI 0.88 to 0.92); M3:0.90 (95% CI 0.88 to 0.92); M4: 0.63 (95% CI 0.60 to 0.66)). At 0.25 injury risk, M2 and M3 demonstrated a 0.43 net benefit improvement. At 0.50 injury risk, M2 and M3 demonstrated a 0.33 net benefit improvement compared with the original model.

CONCLUSION

Model performance was substantially worse in the models with dichotomised variables. This highlights the need to follow established recommendations when developing prediction models.

The Association Between Sleep and Musculoskeletal Injuries in Military Personnel: A Systematic Review

INTRODUCTION

Musculoskeletal injuries (MSKIs) are a significant health problem in the military. Accordingly, identifying risk factors associated with MSKI to develop targeted strategies that attenuate injury risk remains a top priority within the military. Insufficient sleep has garnered increased attention as a potential risk factor for MSKI in both civilians and military personnel. Yet, there are no systematic evaluations of the potential association between sleep and MSKI in the military. The purpose of this review is to examine the relationship between sleep and injury in military personnel.

MATERIALS AND METHODS

Literature searches were performed in multiple electronic databases using keywords relevant to sleep quantity and quality, MSKI, and military populations. Two investigators independently assessed the methodological quality of each study using the Newcastle-Ottawa Scale for cohort studies or an adapted form of this scale for cross-sectional studies.

RESULTS

The search yielded 2402 total citations, with 8 studies (3 cohort and 5 cross-sectional) fitting the inclusion criteria. Overall, the systematic review found 5 of the 8 reviewed studies supporting an association between sleep (quality and duration) and MSKI in military personnel. Specifically, poor sleep was associated with increased injury incidence in 2 cohort and 3 cross-sectional studies.

CONCLUSION

This is the first systematic review to evaluate the published literature on the association between sleep and MSKI risk in military populations. Although there is currently limited research on this topic, findings suggest that sleep is associated with MSKI and should be considered when designing strategies aimed at reducing MSKI risk in military personnel.

Profiles of Recruits Entering Army Basic Training in New Zealand

INTRODUCTION

A high incidence of musculoskeletal injuries is sustained by army recruits during basic training. Describing recruits' personal, lifestyle, and physical performance characteristics at the entry to training can help identify existing intrinsic risk factors that may predispose some recruits to injury. Identifying modifiable and preventable intrinsic risk factors may contribute to lower recruit injury and associated burdens during the course of basic training. The aim of this study was to therefore describe the profile of New Zealand Army recruits upon entry to basic training using personal, lifestyle, and physical performance characteristics.

METHODS

New Zealand Army male and female recruits from two intakes in the same year were invited to participate. Recruits' data on personal (sex, age, height, and weight), lifestyle (self-reported responses to the Military Pre-training Questionnaire comprising physical and injury history, diet, alcohol, and smoking status) and physical performance characteristics (2.4-km timed run, weight-bearing dorsiflexion lunge test, and the Y Balance TestTM for lower limb dynamic stability) were collected and analyzed.

RESULTS

Participants included 248 New Zealand Army recruits: 228 males (91.9%), 20 females (8.1%), average age of 20.3 ± 2.8 years. Findings indicated 30.9% of recruits reported injury in the 12 months prior to training commencing, with 44.8% of those injuries in the lower limbs. Pre-entry alcohol consumption was higher than recommended and 20.1% of recruits identified as current smokers. Recruits who passed the 2.4-km timed run included 53.8% of males and 28.6% of females. Weight-bearing dorsiflexion lunge test performance was within a normal range (right = 10.3 ± 3.3 cm), however limb asymmetry (>1.5 cm) was present with 30.9% of recruits. For the Y Balance TestTM for dynamic lower limb stability, 70% of female recruits had high posterolateral reach asymmetry (8.1 ± 6.0 cm), while normalized composite reach scores were low (right) for male (92.2 ± 8.1%) and female recruits (89.0 ± 7.5%).

CONCLUSIONS

New Zealand Army recruits entering basic training were predominantly active young males, reported few injuries in the previous year, had higher than recommended alcohol consumption and a minority were smokers. The majority of recruits had low aerobic fitness, average ankle dorsiflexion range, and low dynamic lower limb stability. While a number of adverse characteristics identified are potentially modifiable, more research is required to identify an association to musculoskeletal injury risk in New Zealand Army recruits. Describing the profile of recruits entering training, particularly recruits at risk of injury is one of the first steps in injury prevention.

Risk factors for injuries in female soldiers: a systematic review

Background

Female soldiers form an integral part of any modern defence force. Previous reports have highlighted that female soldiers report injuries at higher rates than male personnel. One possible reason for this is an actual difference in underlying injury rates, purported to be due to several factors, including levels of fitness. The aim of this review was to determine risk factors for injuries in female soldiers.

Methods

A systematic search was conducted for studies which reported on risk factors for injuries in female soldiers. Databases searched included PUBMED, CINAHL and Medline through OVID. Eligible studies were rated for their methodological quality using the Critical Appraisal Skills Program (CASP) tools and data were extracted and synthesized using a critical narrative approach.

Results

A total of 18 articles were included in this review which reported on 18 risk factors for injury. Smoking, previous injury, no history of deployment, heavy occupational tasks, lower levels of aerobic fitness and lower number of push-up repetitions appear to be risk factors for injuries in female soldiers. Age, height, body fat, high or low BMI and body mass do not appear to be consistent risk factors for injury in female soldiers and there appears to be minimal evidence for current levels of activity, sit-up ability, and other assessments of strength, power, speed, or movement being associated with injury risk. Additionally, neither flexibility nor previous levels of activity appear to be associated with injury risk in female soldiers.

Conclusion

Strategies to improve aerobic fitness and upper limb endurance, reduce smoking, and optimise rehabilitation from injuries and risk management for heavy occupational tasks need to be developed for female soldiers. Such strategies are also likely to reduce risks for male soldiers.

Predicting Upper Quadrant Musculoskeletal Injuries in the Military: A Cohort Study

PURPOSE

This study aimed to identify characteristics and movement-based tests that predict upper quadrant musculoskeletal injury (UQI) in military personnel over a 12-month follow-up.

METHODS

A prospective observational cohort study of military members (n = 494; 91.9% male) was conducted. Baseline predictors associated with UQI were gathered through surveys and movement-based tests. Survey data included demographic information, injury history, and biosocial factors. Movement-based tests include the following: Y Balance Tests (YBT), Functional Movement Screen, Selective Functional Movement Assessment lumbar multisegmental mobility, modified-modified Schober, side bridge, ankle mobility, modified Sorensen, and passive lumbar extension. Self-reported UQI was collected through monthly online surveys, and 87% completed the follow-up. Univariate associations were determined between potential predictors and UQI. A forward, stepwise logistic regression model was used to identify the best combination of predictors for UQI.

RESULTS

Twenty-seven had UQI. Univariate associations existed with three demographic (smoking, >1 previous UQI, baseline upper quadrant function ≤90%), three pain-related (Selective Functional Movement Assessment rotation, side bridge, hurdle step), and six movement-based variables (YBT upper quarter (UQ) superolateral worst score ≤57.75 cm, YBT-UQ composite worst score ≤81.1%, failed shoulder clearance, Sorenson <72.14 s, in-line lunge total score <15, and in-line lunge asymmetry >1). Smoking, baseline upper quadrant function ≤90%, and YBT-UQ composite score ≤81.1% predicted UQI in the logistic regression while controlling for age and sex. Presenting two or more predictors resulted in good specificity (85.6%; odds ratio, 4.8; 95% confidence interval, 2.2-10.8), and at least one predictor resulted in 81.5% sensitivity (odds ratio, 3.2; 95% confidence interval, 1.2-8.7).

CONCLUSIONS

A modifiable movement-based test (YBT-UQ), perceived upper limb function, and smoking predicted UQI. A specific (two or more) and sensitive (at least one predictor) model could identify persons at higher risk.

Predictors of Temporary Profile Days Among U.S. Army Active Duty Soldiers

Introduction

More than 40,000 soldiers cannot deploy every year, which undermines readiness. The medical readiness of soldiers is a critical component of the overall operational readiness of the U.S. Army. Acute musculoskeletal injuries (MSIs) are the greatest threat to medical readiness. Medical providers place soldiers on temporary profiles to facilitate treatment and recovery of acute MSIs. Poorly managed temporary profiles negatively impact a soldier’s work attendance, resulting in the loss or limitation of over 25 million workdays annually. Upgrading the electronic profile system and implementing the Army Medical Home has led to improvements in managing temporary profiles over the last decade. The Army Medical Home encompasses care delivery platforms, including the Patient-Centered Medical Home (PCMH) and Soldier-Centered Medical Home (SCMH). The structure of U.S. Army PCMHs and SCMHs differ in ways that may affect care processes and patient outcomes. Temporary profile management is an important soldier health outcome that has not been studied in relation to the U.S. Army’s PCMH and SCMH structures or care processes. Access to care, continuity, and communication are three care processes that have been described as essential factors in reducing lost workdays and functional limitations in workers after an acute injury. Understanding the impact of the medical home on temporary profile days is vital to medical readiness. This study aimed to (1) compare temporary profile days between the U.S. Army PCMHs and SCMHs and (2) determine the influence of medical home structures and care processes on temporary profile days among active duty U.S. Army soldiers receiving care for MSIs.

Materials and Methods

This was a retrospective, cross-sectional, and correlational study guided by Donabedian’s conceptual framework. We used secondary data from the Military Data Repository collected in 2018. The sample included 27,214 temporary profile records of active duty U.S. Army soldiers and 266 U.S. Army PCMH and SCMH teams. We evaluated bivariate and multivariate associations between outcomes and predictors using general and generalized linear mixed regression models. The U.S. Army Medical Department Center and School Institutional Review Board approved this study.

Results

Total temporary profile days ranged from 1 to 357, with a mean of 37 days (95% CI [36.2, 37.0]). There was a significant difference in mean temporary profile days between PCMHs (43) and SCMHs (35) (P &lt; 0.001). Soldiers in PCMHs were more likely to have temporary profiles over 90 days (OR = 1.54, 95% CI [1.17, 2.03]). Soldiers in the heavy physical demand category had fewer temporary profile days (P &lt; 0.001) than those in the moderate physical demand category. Age, sex, rank level, physical demand category, profile severity, medical home type, the “explain things” communication subscale, and primary care manager continuity were significant predictors of temporary profile days.

Conclusions

Excessive temporary profile days threaten medical readiness and overall soldier health. Aspects of the medical home structure and care processes were predictors of temporary profile days for musculoskeletal conditions. This work supports continued efforts to improve MSI-related outcomes among soldiers. Knowledge gained from this study can guide future research questions and help the U.S. Army better meet soldier needs.

Recovery, Rehabilitation, and Return to Full Duty in a Military Population After a Recent Injury: Differences Between Lower-Extremity and Spine Injuries

Purpose

To compare readiness to return to duty in soldiers following recent lower-extremity versus spine injury. The secondary purposes were to provide normative data for the Selective Functional Movement Assessment Top Tier movements (SFMA-TTM) and assess the association between SFMA-TTM scores and future injury occurrence, comparing injuries of the lower extremity and thoracic/lumbar spine.

Methods

SFMA was rated by trained assessors on 480 U.S. Army soldiers within 2 weeks of being cleared to return to duty after recent lower-extremity or lumbar/thoracic injury. Participants were followed for 1 year to determine incidence of subsequent time-loss injury.

Results

Only 74.4% of soldiers felt 100% mission capable when returning to full duty (73.6% lower-extremity; 76.5% spine). After 1 year, 37.9% had sustained a time-loss injury, and pain with movement at baseline was associated with higher odds for having an injury (odd ratio 1.53 95% confidence interval 1.04-2.24; P = .032). Almost all (99.8%) had at least 1 dysfunctional pattern, and 44.1% had pain with at least 1 movement (40.3% with previous lower-extremity injury; 54.6% with previous spine injury) after being cleared to return to duty.

Conclusions

One in four patients did not feel 100% mission capable upon being cleared for full duty. Pain with movement was also associated with future injury. Regardless of recent injury type, 99.8% of soldiers returned to full unrestricted duty with at least 1dysfunctional movement pattern and 44.1% had pain with at least 1 of the SFMA-TTM movements.

Level of Evidence

Level III, retrospective comparative cohort study.

Challenges With Engaging Military Stakeholders for Clinical Research at the Point of Care in the U.S. Military Health System

The DoD has a specific mission that creates unique challenges for the conduct of clinical research. These unique challenges include (1) the fact that medical readiness is the number one priority, (2) understanding the role of military culture, and (3) understanding the highly transient flow of operations. Appropriate engagement with key stakeholders at the point of care, where research activities are executed, can mean the difference between success and failure. These key stakeholders include the beneficiaries of the study intervention (patients), clinicians delivering the care, and the military and clinic leadership of both. Challenges to recruitment into research studies include military training, temporary duty, and deployments that can disrupt availability for participation. Seeking medical care is still stigmatized in some military settings. Uniformed personnel, including clinicians, patients, and leaders, are constantly changing, often relocating every 2-4 years, limiting their ability to support clinical trials in this setting which often take 5-7 years to plan and execute. When relevant stakeholders are constantly changing, keeping them engaged becomes an enduring priority. Military leaders are driven by the ability to meet the demands of the assigned mission (readiness). Command endorsement and support are critical for service members to participate in stakeholder engagement panels or clinical trials offering novel treatments. To translate science into relevant practice within the Military Health System, early engagement with key stakeholders at the point of care and addressing mission-relevant factors is critical for success.

Association Between Self-Reported Sleep Quality and Musculoskeletal Injury in Male Army Rangers

INTRODUCTION

Musculoskeletal injuries and insufficient sleep are common among U.S. Army Rangers. There has been limited research into whether indices of sleep differ between injured and uninjured Rangers. The purpose of this study was to investigate the association between self-reported sleep and musculoskeletal injury in Rangers.

MATERIALS AND METHODS

A total of 82 Army Rangers (male, 25.4 ± 4.0 years) were asked if they currently have any musculoskeletal injuries; completed the Pittsburgh Sleep Quality Index (PSQI), the Insomnia Severity Index (ISI), and the Stanford Sleepiness Scale; and were asked about their average sleep quality/sleep duration over the preceding week. Rangers were then dichotomized into groups, one that reported a current musculoskeletal injury and another that did not.

RESULTS

The reported musculoskeletal injury prevalence was 15.9% (n = 13). The Rangers that reported an injury, compared to those that did not, had a significantly higher Global PSQI score (6.7 ± 3.7 versus 4.5 ± 2.7, P = .012) and ISI score (10.9 ± 3.7 versus 7.2 ± 4.1, P = .003), both indicative of poorer sleep. The group reporting an injury rated their average sleep quality over the preceding week significantly lower compared to those that did not report an injury (50.8 ± 17.5 versus 68.9 ± 18.3, P = .001). There was no significant group difference in the average nightly sleep duration (6.1 ± 1.0 hours versus 6.5 ± 0.9 hours, P = .099).

CONCLUSION

In this cohort of male Army Rangers, In this cohort of male Army Rangers, those with a musculoskeletal injury reported poorer sleep quality than uninjured Rangers. Sleep duration was not associated with reported injuries; however, both the injured group and uninjured group averaged less than the recommended amounts of sleep. Further investigation into the relationship between musculoskeletal injury and sleep in military personnel is warranted.

The Relationship Between Functional Movement, Dynamic Stability, and Athletic Performance Assessments in Baseball and Softball Athletes

ABSTRACT

Stapleton, DT, Boergers, RJ, Rodriguez, J, Green, G, Johnson, K, Williams, P, Leelum, N, Jackson, L, and Vallorosi, J. The relationship between functional movement, dynamic stability, and athletic performance assessments in baseball and softball athletes. J Strength Cond Res 35(12S): S42-S50, 2021-Despite recent popularity, the relationship between movement quality and measures of athletic performance remains inconclusive. This investigation sought to clarify the relationships between measures of movement quality and measures of athletic performance in baseball and softball athletes. Thirty-eight National Collegiate Athletic Association Division I baseball (n = 23; age 20.00 ± 1.38 years, lower-extremity [LE] limb length 93.91 ± 4.37, upper-extremity [UE] limb length 92.37 ± 4.48) and softball (n = 15; age 19.93 ± 1.28 years, LE limb length 89.43 ± 4.67, UE limb length 84.61 ± 4.39) athletes completed the Functional Movement Screen (FMS) and the Y Balance Test for the lower and upper extremities (YBTLQ and YBTUQ, respectively). Performance assessments were proagility (PA), vertical jump (VJ), and rotational medicine ball throw to the right and left (RMTR and RMTL, respectively). No significant correlations were seen between any of the composite scores of movement quality and athletic performance in baseball athletes; shoulder mobility was weakly correlated with PA (rs = 0.442, p = 0.035). Composite FMS was negatively correlated with RMTR (rs = -0.753) in softball athletes. In addition, in softball athletes, RMTR was negatively correlated with in-line lunge (rs = -0.544, p = 0.04), trunk stability push-up (rs = -0.761, p = 0.002), anterior YBTLQ reach (r = -0.628), and posterolateral YBTLQ reach (r = -0.683); VJ was correlated with posterolateral YBTLQ reach (r = 0.531) and superolateral (SL) YBTUQ reach (r = 0.591), and PA was negatively correlated with posterolateral YBTLQ (r = -0.60) and SL YBTUQ reach (r = -0.557). The differences in correlations of movement quality and athletic performance between baseball and softball athletes suggest movement quality influences performance differently in female athletes and male athletes.

Systematic Review and Meta-Analysis of the Y-Balance Test Lower Quarter: Reliability, Discriminant Validity, and Predictive Validity

BACKGROUND

Deficits in dynamic neuromuscular control have been associated with post-injury sequelae and increased injury risk. The Y-Balance Test Lower Quarter (YBT-LQ) has emerged as a tool to identify these deficits.

PURPOSE

To review the reliability of the YBT-LQ, determine if performance on the YBT-LQ varies among populations (i.e., sex, sport/activity, and competition level), and to determine the injury risk identification validity of the YBT-LQ based on asymmetry, individual reach direction performance, or composite score.

STUDY DESIGN

Systematic Review.

METHODS

A comprehensive search was performed of 10 online databases from inception to October 30, 2019. Only studies that tested dynamic single leg balance using the YBT-LQ were included. Studies were excluded if the Y-Balance Test kit was not utilized during testing or if there was a major deviation from the Y-Balance test procedure. For methodological quality assessment, the modified Downs and Black scale and the Newcastle-Ottawa Scale were used.

RESULTS

Fifty-seven studies (four in multiple categories) were included with nine studies assessing reliability, 36 assessing population differences, and 16 assessing injury prediction were included. Intra-rater reliability ranged from 0.85-0.91. Sex differences were observed in the posteromedial direction (males: 109.6 [95%CI 107.4-111.8]; females: 102.3 [95%CI 97.2-107.4; p = 0.01]) and posterolateral direction (males: 107.0 [95%CI 105.0-109.1]; females: 102.0 [95%CI 97.8-106.2]). However, no difference was observed between sexes in the anterior reach direction (males: 71.9 [95%CI 69.5-74.5]; females: 70.8 [95%CI 65.7-75.9]; p=0.708). Differences in composite score were noted between soccer (97.6; 95%CI 95.9-99.3) and basketball (92.8; 95%CI 90.4-95.3; p <0.01), and baseball (97.4; 95%CI 94.6-100.2) and basketball (92.8; 95%CI 90.4-95.3; p=0.02). Given the heterogeneity of injury prediction studies, a meta-analysis of these data was not possible. Three of the 13 studies reported a relationship between anterior reach asymmetry reach and injury risk, three of 10 studies for posteromedial and posterolateral reach asymmetry, and one of 13 studies reported relationship with composite reach asymmetry.

CONCLUSIONS

There was moderate to high quality evidence demonstrating that the YBT-LQ is a reliable dynamic neuromuscular control test. Significant differences in sex and sport were observed. If general cut points (i.e., not population specific) are used, the YBT-LQ may not be predictive of injury. Clinical population specific requirements (e.g., age, sex, sport/activity) should be considered when interpreting YBT-LQ performance, particularly when used to identify risk factors for injury.

LEVEL OF EVIDENCE

1b.

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.

Risk factors for musculoskeletal injuries in military personnel: a systematic review with meta-analysis

OBJECTIVE

To investigate the risk factors for musculoskeletal injuries in military personnel.

METHODS

A systematic literature search was carried out in August 2019 and updated in July 2020 without language or time filters. The inclusion criteria were prospective studies that investigated the risk factors for injuries in military personnel. Only risk factors analyzed by at least ten studies were selected for the meta-analysis. For data analysis, the RevMan5.3 program was used to compare the number of participants with injuries between high- or low-risk groups. The measurement of dichotomous variables was one of the selected parameters for the analysis, as well as the Mantel-Haenszel statistical method, random-effects model, and analysis with a relative risk (RR) and 95% confidence interval for the included studies.

RESULTS

A total of 2,629 studies were identified through databases. Thirty-four studies met the inclusion criteria. The groups considered at risk were the oldest [RR = 1.22; (95% CI 1.06-1.41)], with overweight or obesity [RR = 1.27; (95% CI 1.08-1, 48)], with previous injuries [RR = 1.15; (95% CI 1.01-1.30)], and with the worst performance in running tests of 1,600-3,200 m [RR = 1.87; (95% CI 1.28-2.71)]. Gender, ethnicity, and smoking were not associated with injuries. However, a subgroup analysis showed that among studies with a follow-up of fewer than 12 months, women presented RR = 2.44 (95% CI 1.65-3.60) more likely to develop injuries.

CONCLUSION

Age, overweight or obesity, previous injuries, and performance in the 1600-3200 m run are associated with an increased risk of injury in the military.

The Dorsiflexion Range of Motion Screen: A Validation Study

BACKGROUND

Limited ankle dorsiflexion (DF) is associated with ankle sprains and other lower extremity injuries. Current ankle measurements can be laborious to perform in an athletic environment.

PURPOSE

The purpose of this study was to determine the reliability and discriminant validity of a novel closed-chain ankle DF ROM test, the standing ankle dorsiflexion screen (SADS).

STUDY DESIGN

Reliability and validity study.

METHODS

Thirty-seven healthy subjects participated in the study. Two raters measured closed-chain ankle DF range of motion (ROM) using a modified lunge position with an electronic inclinometer. Four raters measured ankle DF using the SADS. Reliability was calculated using intraclass correlation coefficients (ICC) and kappa coefficients for the raters using an electronic inclinometer and the SADS scale, respectively. An independent t-test compared the SADS categories of "behind" and "beyond" to the modified lunge test ROM (p<0.05).

RESULTS

Excellent ICC values (0.95 [95% CI (0.92,0.97)]) and high kappa values were observed (0.61-0.81), with high percent agreement (86-94%). There was a significant difference in ankle DF ROM between the nominally scored "behind" and "beyond" categories, regardless of rater or trial analyzed (behind: 41.3° ± 4.7°; beyond: 51.8°± SD 6.1°, p <0.001).

CONCLUSIONS

The SADS was observed to have excellent interrater reliability and high discriminant validity. Furthermore, there was a distinct closed chain ankle DF ROM difference between the "behind" and "beyond" SADS nominal scores.

CLINICAL RELEVANCE

The SADS can be used as a quick and efficient closed chain ankle DF ROM screen.

LEVEL OF EVIDENCE

2b.

Transitioning from daytime to nighttime operations in military training has a temporary negative impact on dynamic balance and jump performance in U.S. Army Rangers

OBJECTIVES

Explore the impact transitioning from daytime to nighttime operations has on performance in U.S. Army Rangers.

METHODS

Fifty-four male Rangers (age 26.1±4.0 years) completed the Y-Balance Test (YBT), a vertical jump assessment, and a grip strength test at three time points. Baseline testing occurred while the Rangers were on daytime operations; post-test occurred after the first night into the nighttime operation training (after full night of sleep loss), and follow-up testing occurred six days later (end of nighttime training).

RESULTS

On the YBT, performance was significantly worse at post-test compared to baseline during right posteromedial reach (104.1±7.2cm vs 106.5±6.7cm, p=.014), left posteromedial reach (105.4±7.5cm vs 108.5±6.6cm, p=.003), right composite score (274.8±19.3cm vs 279.7±18.1cm, p=.043), left composite score (277.9±18.1cm vs 283.3±16.7cm, p=.016), and leg asymmetry was significantly worse in the posterolateral direction (4.8±4.0cm vs 3.7±3.1cm, p=.030) and the anterior direction (5.0±4.0cm vs 3.6±2.6cm, p=.040). The average vertical jump height was significantly lower at post-test compared to baseline (20.6±3.4 in vs 21.8±3.0 in, p=.004). Baseline performance on YBT and vertical jump did not differ from follow-up.

CONCLUSIONS

Army Rangers experienced an immediate, but temporary, drop in dynamic balance and vertical jump performance when transitioning from daytime to nighttime operations. When feasible, Rangers should consider adjusting their sleep cycles prior to anticipating nighttime operations in order to maintain their performance levels. Investigating strategies that may limit impairments during this transition is warranted.

The Potential Role of Functional Motor Competence to Promote Physical Military Readiness: A Developmental Perspective

Decreased physical fitness in military recruiting populations is problematic for the development of physical military readiness (PMR) and presents a threat to national security. The demonstration of low levels of fitness may be an indicator of a more foundational problem in the physical development of military recruits. We propose the development of functional motor competence (FMC) across childhood and adolescence as a necessary antecedent to advanced PMR training and military-specific tasks (i.e., rucking and obstacle course navigation) and as an integral part of sustained PMR. The development of FMC supports increases in cardiovascular and muscular endurance through repeated efforts performed during practice and in sport, as well as muscular power as many FMC movements mimic plyometrics in a strength in conditioning sense. We posit that an inadequate foundation in FMC will serve as a barrier to achieving sufficient PMR and combat success of the fighting force. We propose three possible solutions to ensure sufficient PMR levels through the implementation of developmentally appropriate FMC-based training. First would be promoting FMC-based training in junior reserve officer training corp and ROTC programs. Second would be a more global approach, on the scale of the National Defense Education Act, specifically focusing on promoting quality daily physical education that could reach millions of children. Third, individual branches could begin promoting the tenets of foundational FMC training concepts in their physical training manuals, which ideally would address FMC before and throughout basic training, as well as subsequent active duty training.

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.

Nonexercise Interventions for Prevention of Musculoskeletal Injuries in Armed Forces: A Systematic Review and Meta-Analysis

CONTEXT

This study evaluates the effect of nonexercise interventions on the reduction of risk for musculoskeletal injuries in armed forces.

EVIDENCE ACQUISITION

A database search was conducted in PubMed/MEDLINE, Embase, Cochrane Library, CINAHL, SPORTdiscus, Greylit, Open Grey, the WHO trial registry, and the reference lists of included articles up to July 2019. RCTs and cluster RCTs evaluating nonexercise interventions for the prevention of musculoskeletal injuries in armed forces compared with any other intervention(s) or no intervention were eligible for inclusion. Data extraction and risk of bias assessment were done by 2 authors independently, followed by meta-analysis and Grading of Recommendations Assessment, Development, and Evaluation assessment, if appropriate.

EVIDENCE SYNTHESIS

This study included 27 articles with a total number of 25,593 participants, examining nutritional supplementation, prophylactic medication, and equipment modifications with mostly high or unclear risk of bias. Meta-analysis and Grading of Recommendations Assessment, Development, and Evaluation assessment could be performed for 3 comparisons: custom-made insoles versus no insoles, tropical/hot-weather boots versus leather boots, and shock-absorbing insoles versus nonshock-absorbing insoles interventions, all showing the very low quality of evidence. Some evidence was found to support the preventive effect of shock-absorbing insoles, basketball shoes, padded polyester socks, calcium with vitamin D supplementation, only calcium supplementation, protein supplementation, and dynamic patellofemoral braces.

CONCLUSIONS

Although an evidence base for the efficacy of preventive interventions for musculoskeletal injuries in armed forces is weak, there are some indications for the preventive effect of shock-absorbing insoles, basketball shoes, padded polyester socks, supplementation of calcium alone or combined with vitamin D, protein supplementation, and dynamic patellofemoral braces on the incidence of 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.

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.

Do Normative Composite Scores on the Functional Movement Screen Differ Across High School, Collegiate, and Professional Athletes? A Critical Review

OBJECTIVE

The Functional Movement Screen (FMS) is a battery of 7 unloaded tests designed to rate human movement competency. Injury rates vary across the different level of a sport. The purpose of this critical review was to determine whether normative FMS composite scores differ across high school, collegiate, and professional athletic populations and to determine whether normative composite scores correlate with rates of severe injury across different collegiate sports.

DATA SOURCES

PubMed, Web of Science, and EBSCO databases from inception to September 2017 with the following syntax: "functional movement screen*" OR "movement screen*". Additional records were identified by citation tracking and hand search of articles.

STUDY SELECTION

A total of 708 records identified, of which 36 were included. Studies were included if they reported a FMS composite score for one of the groups.

DATA EXTRACTION

Two reviewers (T.R.P. and F.K.) screened records for the author and year; sample size; study design; sport(s); number, age, and sex of participants; testing conditions; methodological quality; and mean or median composite score(s).

DATA SYNTHESIS

Normative FMS composite scores were invariant to level of play, with 61% of reported scores falling between 14 and 16, despite injury rates increasing by level of play. Scores for high school, college, and professional athletes were 14.1, 14.8, and 15.7, respectively. There was a significant positive relationship between composite scores and rate of severe injury in college sports (r(11) = 0.66, P = 0.014).

CONCLUSIONS

Our findings potentially undermine the FMS's predictive validity. Although the FMS may have other applications, this critical review provides further evidence against the composite score for injury prediction in competitive athletes.

Trunk endurance, posterior chain flexibility, and previous history of musculoskeletal pain predict overuse low back and lower extremity injury: a prospective cohort study of 545 Navy Cadets

OBJECTIVE

To investigate predictors of low back and lower extremity musculoskeletal injury in a cohort of Naval cadets.

DESIGN

Prospective Cohort Study METHODS: 545 Naval cadets (Males, n = 394, 72%) were followed-up over eight months. Nine variables were investigated as predictors: history of musculoskeletal symptoms in the last 12 months, ankle dorsiflexion range of motion, sit and reach test, isometric hip abduction and external rotation strength, alignment during the single leg squat test, single leg hop test for distance, prone plank and side plank tests. All injuries that required medical attention were registered. Predictive associations were examined using univariable and multivariable logistic regression analyses.

RESULTS

The incidence of all injuries was 7%. Cadets who failed the 60-second plank test (OR = 3.3; 95% CI, 1.2-8.8, P = 0.04), had ≤18 cm in the sit and reach test (OR = 4.0; 95% CI, 1.4-11.2, P = 0.01), or reported pain in the last 12 months in two or more body regions (OR = 2.7; 95% CI, 1.02-7.3, P = 0.04), had greater odds of sustaining an overuse injury. No predictors were identified for acute injuries.

CONCLUSION

Decreased trunk endurance on the prone plank test, reduced posterior chain flexibility on the sit and reach test, and a history of pain reported in two or more sites in the last 12 months were predictors of overuse injuries in Naval cadets. Assessment and intervention of these modifiable risk factors may be clinically relevant in injury screening and prevention.

Integration of strength training into UK Defence Rehabilitation practice: current trends and future challenges

The use of strength and conditioning (S&C) in musculoskeletal rehabilitation has gained wide acceptance among the rehabilitation community. However, there is an absence of evidence demonstrating how to best integrate the principles of S&C into rehabilitation practice. This article discusses four broad themes: (1) an overview of the UK Defence Rehabilitation care pathway, (2) the historical and current approaches to physical training to support operational readiness of the British Armed Forces, (3) the current and future challenges of integrating S&C into Defence Rehabilitation practice and (4) research priorities relating to the use of S&C in Defence Rehabilitation. We detail the importance of strength/power-based physical attributes within our military population. We recommend that consideration be given to the benefits of an alternative education/coaching-based model to be used during the current 3-week residential care pathway, which aims to ensure effective implementation of therapeutic S&C over a longer period of care.

Can Achilles and patellar tendon structures predict musculoskeletal injuries in combat soldiers?

Aiming to investigate whether Achilles tendon (AT) structure and patellar tendon (PT) structure are risk factors for musculoskeletal injuries in combat soldiers, 168 participants were recruited from an infantry commander's course. The AT and PT were examined pre-course using UTC to capture the structure of four echo-type fibers (I-IV). All injuries were assessed by military physicians pre-course and throughout the 14-week course. Soldiers who were injured during the course had a significantly higher pre-course prevalence of AT and PT echo-type III and echo-type IV compared to soldiers that were not injured during the course. Variables that were found to be associated with injured/non-injured participants were echo-type III + IV of the PT (OR = 1.44, 95% CI = 1.24-1.68) and echo-type III of the AT (OR = 1.69, 95% CI = 1.35-2.12). ROC analyses showed that the best model, exhibiting both high sensitivity and low specificity, was that participants with PT echo-type III + IV > 10% or AT echo-type III >8.5% had the highest risk of being injured during the course. In conclusions, the tendon structure at the beginning of high-intensity activity or physical training program might be a risk factor for subsequent injury during the course. Soldiers and high-level athletes should be aware of the cutoff points for fiber types in tendon structure that might put them at high risk for future injury. At-risk soldiers/athletes should be provided with an intervention program before they start their training program, with the aim of improving the tendon structure and preventing subsequent injury.

An Attempt to Utilize the Body Composition Analyzer and the Functional Movement Screen (FMS) Test to Determine Injury Risk in Soldiers

INTRODUCTION

Injuries are the most significant health problem of military services. Military medical surveillance data are useful for determining the magnitude and causes of the injury problem, identifying possible prevention targets and monitoring trends among military personnel. Soldiers serving in the Polish Armed Forces took part in the research. The aim of the study was to identify the most common injuries of the musculoskeletal system and to analyze causes of injuries. An additional goal was to examine whether there is a relationship between selected values of body composition indexes, the result of the functional movement screen (FMS) test and occurrence of an injury.

MATERIAL AND METHODS

The Polish Armed Forces soldiers serving in the land forces, military police, air forces took part in the research. The first stage was to complete the questionnaire regarding injuries in the last 5 years, their reasons, and the circumstances of their occurrence. After completing the survey, subjects were measured and weighed on the body composition analyzer. The next step was to perform a FMS to evaluate the locomotor system.

RESULTS

In the groups of examined Polish soldiers, the most frequent injuries concerned lower limbs and, above all, a knee joint. The leading causes of injuries were activities resulting from the service as well as playing football and volleyball.

CONCLUSIONS

Parameters from the body composition analyzer such as body mass index, muscle mass distribution on lower limbs as well as evaluation in the FMS test may be helpful for the initial assessment of predisposition to injury.

Combining physical performance and Functional Movement Screen testing to identify elite junior Australian Football athletes at risk of injury

The Functional Movement Screen (FMS) and physical performance testing are often suggested to be related to sports injury risk. This study explored if the combination of FMS and physical performance testing improved identification of non-contact injury risk over FMS testing alone in an elite junior Australian football cohort. Over a 3-year period, 573 players completed pre-season injury history questionnaires, FMS, physical performance testing (20-m sprint, vertical jump, planned agility testing, and shuttle run test), and subsequent in-season injury surveillance. Results: Neither previous injury or FMS score <14 were related to an increased risk of subsequent injury in isolation. The combination of FMS composite score ≤14 and previous injury moderately increased the risk of injury (Hazard ratio [HR] = 2.22 [1.09-4.54]). None of the physical performance measures improved the ability to predict injuries based on FMS composite score. FMS asymmetry was only associated with injury when combined with previous injury and vertical jump performance. Players with ≥1 FMS asymmetry and history of previous injury experienced a large increase in injury risk when vertical jump was poor (HR = 4.26 [1.35-13.42]) or good (HR = 3.17 [1.08-9.29]). Players with a combination of a good vertical jump, no previous injury, and no FMS asymmetries were also at moderately increased risk of injury (HR = 3.41 [1.11-10.42]). No physical performance tests improved the ability to identify non-contact injury risk using an FMS composite score threshold. However, a U-shaped relationship between vertical jump and injury risk was identified with both poor and good vertical jump height associated with a moderate-large increase in non-contact injury risk in the presence of ≥1 asymmetrical FMS sub-test.