Prevention of physical training-related injuries recommendations for the military and other active populations based on expedited systematic reviews

Perceived barriers and facilitators to implementation of injury prevention programs in the military: Feedback from inside the trenches

BACKGROUND

Musculoskeletal injuries enact a substantial burden in military settings, incurring high costs, long-term disability, and impacting military readiness. This has led to a prioritization of injury prevention programs. Understanding the challenges faced by those trying to implement these programs could help standardize and better inform future efforts. The purpose was to capture perceptions of barriers and facilitators to implementation of injury prevention programs in the US Armed Forces.

METHODS

A cross-sectional survey with open-ended questions was circulated to relevant stakeholders; key themes were derived using conceptual content analysis. Four questions were asked concerning injury prevention programs: 1) barriers, 2) facilitators, 3) how can leadership best support, and 4) how can subject matter experts best collaborate to make these programs successful?

RESULTS

The survey reached at least 300 individuals working with the armed services worldwide; 91 completed the survey. The mean (SD) time working with military service members was 11.5 (8.2) years; 93 % worked with active-duty service members, 71.4 % were licensed healthcare providers, and 55 % worked in settings with established injury prevention programs. Only 45.2 % of participants believed an appropriate, clear way to measure program success currently exists. Nearly 85 % believed that lacking standardization of definitions and metrics hinders program assessment. Wide variability existed in opinions regarding who should be primarily responsible for promoting/supporting injury prevention efforts. Key themes included resources as both a facilitator (when present) and barrier (when absent), organizational culture, and leadership support. Leadership can best help by prioritizing the programs and valuing the programming through modeling the desired behavior. Program staff can collaborate by focusing on enabling change, integrating into organizational/unit culture and collaborating with leaders to change policy.

CONCLUSIONS

Factors leading to incidence and recovery of musculoskeletal injuries are multifactorial, requiring collaborative multidisciplinary approaches for optimal injury prevention program development and implementation. Leadership support/prioritization, unit-level cultural acceptance and sufficient resources are essential facilitators to implementing prevention programs. Developing standardized, relevant metrics for assessing program effectiveness and establishing organizational best practices are necessary for long term program viability and lasting change.

Multivitamin Compliance Reduces Injuries of Female Recruits at Air Force Basic Training: A Randomized Controlled Cohort Study

INTRODUCTION

Department of the Air Force basic military training (BMT) is the 7.5-week initial entry training for all enlisting U.S. Air Force and Space Force recruits. Overuse musculoskeletal injuries (MSKI) during training threaten success in BMT, and trainees with nutritional deficiencies are at higher risk. Several efforts are made at BMT to mitigate these issues to help trainees graduate on time, such as the distribution of multivitamins (MVI) to female recruits. However, trainee compliance with the prescribed MVI has been reported to be low, calling into question the effectiveness of this intervention. This study evaluated the effect of briefing modality offered to these trainees at the time of distribution on educational effectiveness, MVI compliance, and injury rates.

MATERIALS AND METHODS

This was a randomized controlled cohort study of BMT female trainees. Subjects included all female trainees of a single iteration of BMT concurrently completing training within the same squadron. At the outset of training, cohorts were randomly educated in one of two ways regarding the provided MVI. The control cohort (n = 80) was presented with the standard educational video created by BMT-registered dietitians, while the test cohort (n = 79) was presented the video and then also briefed in-person by a group of subject matter experts. At the end of BMT, the trainees completed a questionnaire regarding their knowledge, confidence, and compliance with the MVI. Additionally, a routinely collected training database was queried and analyzed for differences in injuries and training outcomes using the chi-squared test with significance set to α ≤ 0.05.

RESULTS

Although both cohorts found their educational presentation useful, the "in-person" cohort reported significantly higher compliance rates and were found to be diagnosed with MSKI and bone stress injuries at significantly lower rates (43% and 66% relative risk reductions, respectively).

CONCLUSIONS

Education to female BMT trainees regarding the MVI, which included a face-to-face discussion with subject matter experts, resulted in greater compliance and reduced incidence of MSKI and bone stress injury, compared to a video prepared by registered dietitians alone. Such educational approaches should continue to be strived for in this and other military population health measures. This study's implication of MVI efficacy for injury risk reduction in female trainees should be further studied, verified, and improved upon in this and other populations.

Does policy that provides choice in athletic footwear affect musculoskeletal injury risk in US Coast Guard recruits?

INTRODUCTION

Musculoskeletal injuries (MSKIs) are ubiquitous during initial entry military training, with overuse injuries the most common. A common injury mechanism is running, an activity that is integral to US Coast Guard (USCG) training and a requirement for graduation. The purpose of this study was to assess the effects of a policy that allowed for athletic footwear choice on risk of lower quarter MSKI in USCG recruits.

METHODS

A retrospective cohort study was performed that included 1230 recruits (1040 men, 190 women) who trained under a policy that allowed self-selection of athletic footwear and 2951 recruits (2329 men, 622 women) who trained under a policy that mandated use of prescribed uniform athletic shoes and served as controls. Demographic data and physical performance were derived from administrative records. Injury data were abstracted from a medical tracking database. Unadjusted risk calculations and multivariable logistic regression assessing the effects of group, age, sex, height, body mass and 2.4 km run times on MSKI were performed.

RESULTS

Ankle-foot, leg, knee and lumbopelvic-hip complex injuries were ubiquitous in both groups (experimental: 13.13 per 1000 person-weeks; control: 11.69 per 1000 person-weeks). Group was not a significant factor for any of the injuries assessed in either the unadjusted or adjusted analysis, despite widespread reports of pain (58.6%), perceived injury attribution (15.7%), perceived deleterious effect on performance (25.3%), general dissatisfaction (46.3%) and intended discontinuance of use following graduation (87.7%).

CONCLUSION

MSKI continues to be a major source of morbidity in the recruit training population. The policy that allowed USCG recruits to self-select athletic footwear did not decrease or increase the risk of MSKI. While regulations pertaining to footwear choice did not influence injury outcomes, there was general dissatisfaction with the prescribed uniform athletic footwear conveyed by the recruits and widespread reports of discomfort, perceived deleterious effects from wear and intended discontinued use following training completion.

Role of nutrition in human performance in military populations

The role of nutrition and performance is well established. Service members' physical and cognitive performance, sleep and mood are impacted by nutritional choices. Although many eating patterns have emerged, consensus among experts recommend a dietary pattern focused on predominantly whole plant-based foods. Adequate intakes of fruits, vegetables, whole grains, beans, legumes, nuts and seeds should be prioritised. Implementation of strategic and intentional fuelling strategies around times of activity maintain adequate energy stores, enhance recovery and protect against training injuries. Carbohydrates are prioritised before, during and after activity or a mission, although the type and amount will vary based on duration and intensity of activity. Protein is generally the focus after activity or a mission and may be included before activity depending on individual tolerance. There are no specific recommendations for fat consumption before, during and after exercise that will improve performance. That said, Service members generally tolerate low-fat meals/snacks prior to exercise, limit fat intake during exercise, may include fat as part of the post exercise meal/snack, and generally consume most fat during the maintenance and growth phase. Careful consideration and planning for food and fluid requirements should be made when Service members are exposed to heat, cold and/or altitude. Operational rations are formulated to meet the nutritional needs of all Service members across a variety of diverse climates, environments and altitudes. Service members may use dietary supplements to improve their performance and need to be aware of available resources to help them make informed decisions.

The effect of a suspension training on physical fitness, lower extremity biomechanical factors, and occupational health in Navy personnel: a randomized controlled trial

Optimal physical fitness is essential for military personnel to effectively meet their rigorous physical demands. This study aimed to investigate the effectiveness of a suspension training program on physical fitness, biomechanical risk factors for lower extremity injury, mental health, and work-related factors in Navy personnel. A total of 50 young men participated in a randomized controlled trial. The participants were randomly assigned to two groups (n = 25): the intervention group and the control group. The intervention group performed an eight-week suspension training session three times per week, while the control group maintained their daily duties. The primary outcome was physical performance. The secondary outcomes were determined biomechanical risk factors for lower extremity injuries, mental health, and work-related factors. The data were analyzed using the analysis of covariance (ANCOVA). Compared with the control group, the intervention group showed significant improvements in physical performance, biomechanical risk for lower extremity injuries, and work-related factors from baseline to follow-up (p ≤ 0.05). However, there was no improvement in mental health. Based on these findings, suspension training positively impacted physical fitness, reduced injury risk, and enhanced the work-related factors of Navy personnel. This study provides new insights for various related experts and military coaches because it is an easy-to-use and feasible method with minimal facilities.

Prescribed footwear and orthoses are not prophylactic in preventing lower extremity injuries in military tactical athletes: a systematic review with meta-analysis

INTRODUCTION

Military members are exposed to high cumulative physical loads that frequently lead to injury. Prescribed footwear and orthoses have been used to prevent injury. The purpose of this systematic review with meta-analysis was to assess if prescribed prophylactic footwear or foot orthoses reduced the risk of lower extremity injury in military tactical athletes.

METHODS

MEDLINE, Embase, Web of Science, Cumulative Index to Nursing and Allied Health Literature, SportDiscus, and Defense Technical Information Center databases were searched for randomised controlled trials published at any time that compared foot orthoses or prescribed footwear (to include shock-absorbing insoles and socks) with a placebo intervention or a no-treatment control. Methodological quality was assessed and the number of injuries, population at risk and duration of the study epoch were extracted and relative risk (RR) calculated. An omnibus meta-analysis was performed assessing all prescribed footwear and orthoses intervention studies, with subgroup analyses conducted on studies with similar interventions (ie, basketball athletic shoes, athletic shoes (prescribed by foot type), foot orthoses, shock-absorbing insoles, socks, tropical combat boots).

RESULTS

Of 1673 studies identified, 22 were included. Three of eight studies that employed orthoses demonstrated significantly reduced overuse injuries compared with no-treatment controls (RR range: 0.34-0.68); one study showed neoprene insoles significantly decreased overuse injuries (RR: 0.75). There were no other significant effects in the individual studies and no protective effects observed in the omnibus meta-analysis or in the component subanalyses.

CONCLUSIONS

Prescribed footwear and orthoses do not appear to have a prophylactic effect on lower quarter musculoskeletal injuries in military members and cannot be recommended at this time.

Barriers and facilitators to implementation of musculoskeletal injury mitigation programmes for military service members around the world: a scoping review

INTRODUCTION

Musculoskeletal injury (MSK-I) mitigation and prevention programmes (MSK-IMPPs) have been developed and implemented across militaries worldwide. Although programme efficacy is often reported, development and implementation details are often overlooked, limiting their scalability, sustainability and effectiveness. This scoping review aimed to identify the following in military populations: (1) barriers and facilitators to implementing and scaling MSK-IMPPs; (2) gaps in MSK-IMPP research and (3) future research priorities.

METHODS

A scoping review assessed literature from inception to April 2022 that included studies on MSK-IMPP implementation and/or effectiveness in military populations. Barriers and facilitators to implementing these programmes were identified.

RESULTS

From 132 articles, most were primary research studies (90; 68.2%); the remainder were review papers (42; 31.8%). Among primary studies, 3 (3.3%) investigated only women, 62 (69%) only men and 25 (27.8%) both. Barriers included limited resources, lack of stakeholder engagement, competing military priorities and equipment-related factors. Facilitators included strong stakeholder engagement, targeted programme design, involvement/proximity of MSK-I experts, providing MSK-I mitigation education, low burden on resources and emphasising end-user acceptability. Research gaps included variability in reported MSK-I outcomes and no consensus on relevant surveillance metrics and definitions.

CONCLUSION

Despite a robust body of literature, there is a dearth of information about programme implementation; specifically, barriers or facilitators to success. Additionally, variability in outcomes and lack of consensus on MSK-I definitions may affect the development, implementation evaluation and comparison of MSK-IMPPs. There is a need for international consensus on definitions and optimal data reporting elements when conducting injury risk mitigation research in the military.

Association of Dynamic Knee Valgus and Bone Stress Injury in US Military Academy Cadets

CONTEXT

Early identification of incoming military personnel at elevated odds for bone stress injury (BSI) is important for the health and readiness of the US military.

DESIGN

Prospective cohort study.

METHODS

Knee kinematic data of the incoming US Military Academy cadets were collected while performing a jump-landing task (The Landing Error Scoring System) using a markerless motion capture system and depth camera. Data on incidence of lower-extremity injury, including BSI, were collected throughout the study period.

RESULTS

A total of 1905 participants (452 females, 23.7%) were examined for knee valgus and BSI status. A total of 50 BSI occurred during the study period (incidence proportion = 2.6%). The unadjusted odds ratio for BSI at initial contact was 1.03 (95% confidence interval [CI], 0.94-1.14; P = .49). Adjusted for sex, the odds ratio for BSI at initial contact was 0.97 (95% CI, 0.87-1.06; P = .47). At the instant of maximum knee-flexion angle, the unadjusted odds ratio was 1.06 (95% CI, 1.02-1.10; P = .01), and the odds ratio was 1.02 (95% CI, 0.98-1.07; P = .29) after adjusting for sex. This suggests that there was not a significant enough association for an increase in the odds of BSI based on either degree of knee valgus.

CONCLUSIONS

Our results did not demonstrate an association between knee valgus angle data during a jump-landing task and future increased odds of BSI in a military training population. Further analysis is warranted, but the results suggests the association between kinematics and BSI cannot be effectively screened by knee valgus angle data in isolation.

Efficacy of Army Combat Fitness Test 12-Week Virtual Exercise Program

INTRODUCTION

The Army Combat Fitness Test (ACFT) is the fitness assessment used by the Army launched in April of 2022. The ACFT consists of six physically demanding motor movements that parallel to the stressors experienced by the modern-day combat soldier. The aim of this study is to determine the efficacy of a 12-week virtual exercise program on the individual and their overall ACFT scores.

MATERIALS AND METHODS

Thirteen soldiers from the Army National Guard (age = 29.8 ± 6.2 years; height = 175.7 ± 6.1 cm; service experience ≥ 18 months to 18 years) volunteered to complete three sessions. In session 1, baseline height, body mass, body composition, and ACFT scores were collected. Session 2 consisted of a suspension trainer (ST) tutorial in which all participants familiarized themselves with the set-up and utilization of the suspension training tool kit. Upon completion of session 2, a TRX Elite ACFT Kit containing one suspension trainer, four resistance bands, and the 12-week virtual exercise training program available via iphone operating system and Android were given to all participants. In session 3, post-assessments of body mass, body composition, and ACFT scores were collected. Data were statistically analyzed using a paired-sample t-test with a Bonferroni correction (P < .00065) to adjust for multiple comparisons.

RESULTS

There were no significant changes in mean body mass (83.8 ± 16.5 kg vs. 83.9 ± 16.6 kg; P = .752); however, there was a significant reduction in mean percentage body fat (19.5 ± 6.4% vs. 18.3 ± 6.5%; P < .0001). Mean scores from four of the six individual ACFT assessments, specifically, deadlift, standing power throw, hand-release push-ups, and sprint-drag-carry, displayed improvements, but did not attain statistical significance. The overall mean ACFT scores displayed significant improvements (319.4 ± 39.9 vs. 390.4 ± 68.5; P < .0001).

CONCLUSIONS

The TRX Elite ACFT Kit which includes one suspension trainer, four varying resistance bands, and on-demand access to a stepwise 12-week virtual exercise program was deemed effective by increasing the overall mean ACFT scores among participants. From a practitioner's perspective, the TRX Elite ACFT Kit should be widely distributed to all Army units and recruiting commands to provide vital assistance for recruits and soldiers to train and prepare for the ACFT. Moreover, given the ease and portability of the TRX Elite ACFT Kit, recruits and soldiers will be able to effectively train anytime, anywhere.

Comparison of optimized machine learning approach to the understanding of medial tibial stress syndrome in male military personnel

PURPOSE

This study investigates the applicability of optimized machine learning (ML) approach for the prediction of Medial tibial stress syndrome (MTSS) using anatomic and anthropometric predictors.

METHOD

To this end, 180 recruits were enrolled in a cross-sectional study of 30 MTSS (30.36 ± 4.80 years) and 150 normal (29.70 ± 3.81 years). Twenty-five predictors/features, including demographic, anatomic, and anthropometric variables, were selected as risk factors. Bayesian optimization method was used to evaluate the most applicable machine learning algorithm with tuned hyperparameters on the training data. Three experiments were performed to handle the imbalances in the data set. The validation criteria were accuracy, sensitivity, and specificity.

RESULTS

The highest performance (even 100%) was observed for the Ensemble and SVM classification models while using at least 6 and 10 most important predictors in undersampling and oversampling experiments, respectively. In the no-resampling experiment, the best performance (accuracy = 88.89%, sensitivity = 66.67%, specificity = 95.24%, and AUC = 0.8571) was achieved for the Naive Bayes classifier with the 12 most important features.

CONCLUSION

The Naive Bayes, Ensemble, and SVM methods could be the primary choices to apply the machine learning approach in MTSS risk prediction. These predictive methods, alongside the eight common proposed predictors, might help to more accurately calculate the individual risk of developing MTSS at the point of care.

Effect of sex and combat employment on musculoskeletal injuries and medical downgrading in trained military personnel: an observational cohort study

INTRODUCTION

Following the opening of all combat roles to women across the UK Armed Forces, there is a requirement to understand the risk of injury to these female personnel. Women injure at a higher rate than men during basic military training, but fewer data are published from individuals who have passed military training.

METHODS

A bespoke survey was designed to investigate differences in injury prevalence and medical downgrading between sexes and career employment groups (ie, job roles) in the UK Armed Forces.

RESULTS

Questionnaire data were evaluated from 847 service personnel (87% men) employed in combat roles (Royal Marines, Infantry, Royal Armoured Corps, Royal Air Force Regiment (all men)) and non-combat roles (Royal Regiment of Artillery, Corps of Royal Engineers, Royal Logistic Corps and Combat Service Support Corps who were attached to one of the participating units (men and women)). Women reported more total (OR 1.64 (95% CI: 1.03 to 2.59), p=0.035), lower limb (OR 1.92 (95% CI: 1.23 to 2.98), p=0.004) and hip (OR 2.99 (95% CI: 1.59 to 5.62), p<0.001) musculoskeletal injuries in the previous 12 months than men, but there were no sex differences in the prevalence of current or career medical downgrading due to musculoskeletal injury (both p>0.05). There were no differences in 12-month musculoskeletal injury prevalence between men in combat roles and men in non-combat roles (all p>0.05), but men in non-combat roles were more likely to be currently medically downgraded (OR 1.88 (95% CI: 1.27 to 2.78), p=0.001) and medically downgraded during their career (OR 1.49 (95% CI: 1.11 to 2.00), p=0.008) due to musculoskeletal injury than men in combat roles. More time in service and quicker 1.5-mile run times were associated with increased prevalence of total musculoskeletal injuries, and female sex was a predictor of hip injury.

CONCLUSIONS

Although women are at greater risk of injury than men, we have no evidence that combat employment is more injurious than non-combat employment. The prevention of hip injuries should form a specific focus of mitigation efforts for women.

Gender data gap in military research: a review of the participation of men and women in military musculoskeletal injury studies

Servicewomen are at increased risk of musculoskeletal injuries compared with their male counterparts, but women are under-represented in sports medicine research. The aim of this review was to assess the representation of women in military musculoskeletal injury studies. PubMed was searched for human original research studies using the terms Military OR Army OR Navy OR 'Air Force' AND 'musculoskeletal injury' Each study was categorised as epidemiology (basic training), epidemiology (trained personnel), risk factors, interventions and other. The number of male and female participants was retrieved from each study. A total of 262 studies were included: 98 (37%) studies only included men, 17 (6%) studies only included women and 147 (56%) studies included both men and women. A total of 8 051 778 participants were included in these studies (men: 6 711 082, 83%; women: 1 340 696, 17%). The study theme with the greatest proportion of women was musculoskeletal injury epidemiology studies in a basic training population (20% of participants) with the lowest proportion of women in intervention trials (6% of participants). These data suggest women are not under-represented in military musculoskeletal injury studies when considering the gender representation of most militaries. Our data are, however, biased by large epidemiological trials and women were under-represented in intervention trials. The under-representation of women in intervention trials could be due to difficulties in controlling for the effects of female sex steroids on musculoskeletal outcomes, or a focus on interventions in the most arduous military roles where injury risk is highest and women have been previously excluded.

Running shoes for preventing lower limb running injuries in adults

BACKGROUND

Lower-limb running injuries are common. Running shoes have been proposed as one means of reducing injury risk. However, there is uncertainty as to how effective running shoes are for the prevention of injury. It is also unclear how the effects of different characteristics of running shoes prevent injury.

OBJECTIVES

To assess the effects (benefits and harms) of running shoes for preventing lower-limb running injuries in adult runners.

SEARCH METHODS

We searched the following databases: CENTRAL, MEDLINE, Embase, AMED, CINAHL Plus and SPORTDiscus plus trial registers WHO ICTRP and ClinicalTrials.gov. We also searched additional sources for published and unpublished trials. The date of the search was June 2021.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs involving runners or military personnel in basic training that either compared a) a running shoe with a non-running shoe; b) different types of running shoes (minimalist, neutral/cushioned, motion control, stability, soft midsole, hard midsole); or c) footwear recommended and selected on foot posture versus footwear not recommended and not selected on foot posture for preventing lower-limb running injuries. Our primary outcomes were number of people sustaining a lower-limb running injury and number of lower-limb running injuries. Our secondary outcomes were number of runners who failed to return to running or their previous level of running, runner satisfaction with footwear, adverse events other than musculoskeletal injuries, and number of runners requiring hospital admission or surgery, or both, for musculoskeletal injury or adverse event.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility and performed data extraction and risk of bias assessment. The certainty of the included evidence was assessed using GRADE methodology.

MAIN RESULTS

We included 12 trials in the analysis which included a total of 11,240 participants, in trials that lasted from 6 to 26 weeks and were carried out in North America, Europe, Australia and South Africa. Most of the evidence was low or very low certainty as it was not possible to blind runners to their allocated running shoe, there was variation in the definition of an injury and characteristics of footwear, and there were too few studies for most comparisons. We did not find any trials that compared running shoes with non-running shoes. Neutral/cushioned versus minimalist (5 studies, 766 participants) Neutral/cushioned shoes may make little or no difference to the number of runners sustaining a lower-limb running injuries when compared with minimalist shoes (low-certainty evidence) (risk ratio (RR) 0.77, 95% confidence interval (CI) 0.59 to 1.01). One trial reported that 67% and 92% of runners were satisfied with their neutral/cushioned or minimalist running shoes, respectively (RR 0.73, 95% CI 0.47 to 1.12). Another trial reported mean satisfaction scores ranged from 4.0 to 4.3 in the neutral/ cushioned group and 3.6 to 3.9 in the minimalist running shoe group out of a total of 5. Hence neutral/cushioned running shoes may make little or no difference to runner satisfaction with footwear (low-certainty evidence). Motion control versus neutral / cushioned (2 studies, 421 participants) It is uncertain whether or not motion control shoes reduce the number of runners sustaining a lower-limb running injuries when compared with neutral / cushioned shoes because the quality of the evidence has been assessed as very low certainty (RR 0.92, 95% CI 0.30 to 2.81). Soft midsole versus hard midsole (2 studies, 1095 participants) Soft midsole shoes may make little or no difference to the number of runners sustaining a lower-limb running injuries when compared with hard midsole shoes (low-certainty of evidence) (RR 0.82, 95% CI 0.61 to 1.10). Stability versus neutral / cushioned (1 study, 57 participants) It is uncertain whether or not stability shoes reduce the number of runners sustaining a lower-limb running injuries when compared with neutral/cushioned shoes because the quality of the evidence has been assessed as very low certainty (RR 0.49, 95% CI 0.18 to 1.31). Motion control versus stability (1 study, 56 participants) It is uncertain whether or not motion control shoes reduce the number of runners sustaining a lower-limb running injuries when compared with stability shoes because the quality of the evidence has been assessed as very low certainty (RR 3.47, 95% CI 1.43 to 8.40). Running shoes prescribed and selected on foot posture (3 studies, 7203 participants) There was no evidence that running shoes prescribed based on static foot posture reduced the number of injuries compared with those who received a shoe not prescribed based on foot posture in military recruits (Rate Ratio 1.03, 95% CI 0.94 to 1.13). Subgroup analysis confirmed these findings were consistent between males and females. Therefore, prescribing running shoes and selecting on foot posture probably makes little or no difference to lower-limb running injuries (moderate-certainty evidence). Data were not available for all other review outcomes.

AUTHORS' CONCLUSIONS

Most evidence demonstrates no reduction in lower-limb running injuries in adults when comparing different types of running shoes. Overall, the certainty of the evidence determining whether different types of running shoes influence running injury rates was very low to low, and as such we are uncertain as to the true effects of different types of running shoes upon injury rates. There is no evidence that prescribing footwear based on foot type reduces running-related lower-limb injures in adults. The evidence for this comparison was rated as moderate and as such we can have more certainty when interpreting these findings. However, all three trials included in this comparison used military populations and as such the findings may differ in recreational runners.  Future researchers should develop a consensus definition of running shoe design to help standardise classification. The definition of a running injury should also be used consistently and confirmed via health practitioners. More researchers should consider a RCT design to increase the evidence in this area. Lastly, future work should look to explore the influence of different types or running shoes upon injury rates in specific subgroups.

Safety interventions for the prevention of accidents at work: A systematic review

Background

Limited knowledge regarding the relative effectiveness of workplace accident prevention approaches creates barriers to informed decision-making by policy makers, public health practitioners, workplace, and worker advocates.

Objectives

The objective of this review was to assess the effectiveness of broad categories of safety interventions in preventing accidents at work. The review aims to compare effects of safety interventions to no intervention, usual activities, or alternative intervention, and if possible, to examine which constituent components of safety intervention programs contribute more strongly to preventing accidents at work in a given setting or context.

Date Sources

Studies were identified through electronic bibliographic searches, government policy databanks, and Internet search engines. The last search was carried out on July 9, 2015. Gray literature were identified by searching OSH ROM and Google. No language or date restrictions were applied. Searches done between February and July of 2015 included PubMed (1966), Embase (1980), CINAHL (1981), OSH ROM (NIOSHTIC 1977, HSELINE 1977, CIS-DOC 1974), PsycINFO (1806), EconLit (1969), Web of Science (1969), and ProQuest (1861); dates represent initial availability of each database. Websites of pertinent institutions (NIOSH, Perosh) were also searched.

Study Eligibility Criteria Participants and Interventions

Included studies had to focus on accidents at work, include an evaluation of a safety intervention, and have used injuries at work, or a relevant proxy, as an outcome measure. Experimental, quasi-experimental, and observational study designs were utilized, including randomized controlled trials (RCTs), controlled before and after (CBA) studies, and observational designs using serial measures (interrupted time series, retrospective cohort designs, and before and after studies using multiple measures). Interventions were classified by approach at the individual or group level, and broad categories based on the prevention approach including modification of: Attitudes (through information and persuasive campaign messaging).Behaviors (through training, incentives, goal setting, feedback/coaching).Physiological condition (by physical training).Climate/norms/culture (by coaching, feedback, modification of safety management/leadership).Structural conditions (including physical environment, engineering, legislation and enforcement, sectorial-level norms). When combined approaches were used, interventions were termed "multifaceted," and when an approach(es) is applied to more than one organizational level (e.g., individual, group, and/or organization), it is termed "across levels."

Study Appraisal and Synthesis Methods

Narrative report review captured industry (NACE), work setting, participant characteristics, theoretical basis for approach, intervention fidelity, research design, risk of bias, contextual detail, outcomes measures and results. Additional items were extracted for studies with serial measures including approaches to improve internal validity, assessments of reasonable statistical approaches (Effective Practice of Organization of Care [EPOC] criteria) and overall inference. Random-effects inverse variance weighted meta-analytic methods were used to synthesize odds ratios, rate ratios, or standardized mean differences for the outcomes for RCT and CBA studies with low or moderate levels of heterogeneity. For studies with greater heterogeneity and those using serial measures, we relied on narrative analyses to synthesize findings.

Results

In total 100 original studies were included for synthesis analysis, including 16 RCT study designs, 30 CBA study designs, and 54 studies using serial measures (ITS study designs). These studies represented 120 cases of safety interventions. The number of participants included 31,971,908 individuals in 59 safety interventions, 417,693 groups/firms in 35 safety interventions, and 15,505 injuries in 17 safety interventions. Out of the 59 safety interventions, two were evaluating national prevention measures, which alone accounted for 31,667,110 individuals. The remaining nine safety interventions used other types of measures, such as safety exposure, safety observations, gloves or claim rates. Strong evidence supports greater effects being achieved with safety interventions directed toward the group or organization level rather than individual behavior change. Engineering controls are more effective at reducing injuries than other approaches, particularly when engineered changes can be introduced without requiring "decision-to-use" by workplaces. Multifaceted approaches combining intervention elements on the organizational level, or across levels, provided moderate to strong effects, in particular when engineering controls were included. Interventions based on firm epidemiologic evidence of causality and a strong conceptual approach were more effective. Effects that are more modest were observed (in short follow-up) for safety climate interventions, using techniques such as feedback or leadership training to improve safety communication. There was limited evidence for a strong effect at medium-term with more intense counseling approaches. Evidence supports regulation/legislation as contributing to the prevention of accidents at work, but with lower effect sizes. Enforcement appears to work more consistently, but with smaller effects. In general, the results were consistent with previous systematic reviews of specific types of safety interventions, although the effectiveness of economic incentives to prevent accidents at work was not consistent with our results, and effectiveness of physiological safety intervention was only consistent to some extent.

Limitations

Acute musculoskeletal injuries and injuries from more long-time workplace exposures were not always clearly distinguished in research reports. In some studies acute and chronic exposures were mixed, resulting in inevitable misclassification. Of note, the classification of these events also remains problematic in clinical medicine. It was not possible to conduct meta-analyses on all types of interventions (due to variability in approach, context, and participants). The findings presented for most intervention types are from limited sources, and assessment of publication bias was not possible. These issues are not surprising, given the breadth of the field of occupational safety. To incorporate studies using serial measures, which provide the only source of information for some safety interventions such as legislation, we took a systematic, grounded approach to their review. Rather than requiring more stringent, specific criteria for inclusion of ITS studies, we chose to assess how investigators justified their approach to design and analyses, based on the context in which they were working. We sought to identify measures taken to improve external validity of studies, reasonable statistical inference, as well as an overall appropriate inferential process. We found the process useful and enlightening. Given the new approach, we may have failed to extract points others may find relevant. Similarly, to facilitate the broad nature of this review, we used a novel categorization of safety interventions, which is likely to evolve with additional use. The broad scope of this review and the time and resources available did not allow for contacting authors of original papers or seeking translation of non-English manuscripts, resulting in a few cases where we did not have sufficient information that may have been possible to obtain from the authors.

Conclusions and Implications of Key Findings

Our synthesis of the relative effectiveness of workplace safety interventions is in accordance with the Public Health Hierarchy of Hazard Control. Specifically, more effective interventions eliminate risk at the source of the hazard through engineering solutions or the separation of workers from hazards; effects were greater when these control measures worked independently of worker "decision-to-use" at the worksite. Interventions based on firm epidemiological evidence of causality and clear theoretical bases for the intervention approach were more effective in preventing injuries. Less effective behavioral approaches were often directed at the prevention of all workplace injuries through a common pathway, such as introducing safety training, without explicitly addressing specific hazards. We caution that this does not mean that training does not play an essential function in worker safety, but rather that it is not effective in the absence of other efforts. Due to the potential to reach large groups of workers through regulation and enforcement, these interventions with relatively modest effects, could have large population-based effects.

Association Between Landing Error Scoring System (LESS) Items and the Incidence Rate of Lower Extremity Stress Fracture

Background:

Lower extremity stress fracture injuries are a major cause of morbidity in physically active populations. The ability to screen for modifiable risk factors associated with injury is critical in developing injury-prevention programs.

Purpose:

To determine if baseline Landing Error Scoring System (LESS) scores are associated with the incidence rate of lower extremity stress fracture.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

A total of 1772 participants with no history of lower extremity stress fracture were included. At preinjury baseline, the authors conducted a lower extremity movement assessment during a jump-landing task using the LESS. Incident lower extremity stress fractures were identified during a 4-year follow-up period. Potential incident cases were reviewed by 2 sports medicine fellowship–trained orthopaedic surgeons blinded to baseline LESS data. Univariate and multivariable Poisson regression models were used to estimate the association between baseline total LESS scores, individual LESS items, and the incidence rate ratio (IRR) of lower extremity stress fracture.

Results:

A total of 94 incident lower extremity stress fractures were documented, for a 5.3% (95% CI, 4.3%-6.5%) cumulative incidence. The overall LESS score was associated with the incidence rate of lower extremity stress fracture. For every additional movement error documented at baseline, there was a 15% increase in the incidence rate of lower extremity stress fracture (IRR, 1.15 [95% CI, 1.02-1.31]; P = .025). In univariate analyses, ankle flexion, stance width, asymmetrical landing, and trunk flexion at initial contact, in addition to overall impression, were associated with the incidence rate of stress fracture. After controlling for sex and year of entry into the study cohort, participants who consistently landed flat-footed or heel-to-toe were 2.33 times (95% CI, 1.36-3.97; P = .002) more likely to sustain a lower extremity stress fracture. Similarly, participants who consistently demonstrated asymmetric landing at initial contact were 2.53 times (95% CI, 1.34-4.74; P = .004) more likely to sustain a stress fracture.

Conclusion:

Components of the LESS may be associated with increased lower extremity stress fracture risk and may be helpful in efficiently assessing high-risk lower extremity biomechanics in large groups.

One out of four recruits drops out from elite military training due to musculoskeletal injuries in the Netherlands Armed Forces

INTRODUCTION

Musculoskeletal injuries (MSIs) are among the main causes of dropout from military training. The main purpose of this study was to provide an overview of dropout rates and MSI incidence rates during elite military training. Second, this study aimed to explore restricted training days due to MSIs and to describe MSI-care by military physicians.

METHODS

In a retrospective observational study, we collected dropout rates and injury surveillance data from the electronic patient records of two elite units of the Netherlands Armed Forces (NAF): the Royal Netherlands Marine Corps (RNLMC) and the Airmobile Brigade (AMB), from 1 January 2015 until 31 December 2017.

RESULTS

In the RNLMC, total dropout rate was 53.9% and dropout due to MSIs was 23%. The most frequently affected locations were foot, knee and leg. In the AMB total dropout rate was 52.6% and dropout due to MSIs was 25%. In the AMB, the most frequently affected locations were back, knee and leg. Average restricted training days due to MSIs ranged between 8.3 and 20.8 days/injury. MSI-care by military physicians consisted mostly of the provision of injury-specific information and (self-)management options, imposing a specific activity restriction and referral to physiotherapy.

CONCLUSION

Our study findings showed that one out of four recruits who dropout from elite military training in the NAF, do so due to MSIs. Redesigning training programmes with the objective to reduce MSIs should be given high priority, as this may reduce dropout substantially.

Ankle Sprain Bracing Solutions and Future Design Consideration for Civilian and Military Use

INTRODUCTION

Ankle sprains are common injuries within the civilian and military populations, with lingering symptoms that include pain, swelling, giving-way, and a high likelihood for recurrence. Numerous bracing systems are available to stabilize the ankle joint following sprains, with new design iterations frequently entering the market. Currently available braces generally include sleeve, lace-up, and stirrup designs. Sleeves provide mild compression and warmth but limited stability for the ankle, while lace-ups and stirrups appear to be more effective at preventing and treating lateral ankle sprains.

AREAS COVERED

This review summarizes the use of various brace options in practice. Their major clinical benefits, and limitations are highlighted, followed by an overview of emerging concepts in brace design. Current advancements in biomechanical simulation, multifunctional material fabrication, and wearable, field-deployed devices for human injury surveillance are discussed, providing possibilities for conceiving new design concepts for next-generation smart ankle braces.

EXPERT OPINION

Performance of the commercially available braces are limited by their current design concepts. Suggestions on future brace design include: (1) incorporating high-performance materials suitable for extreme environments, (2) leveraging modeling and simulation techniques to predict mechanical support requirements, and (3) implementing adaptive, customizable componentry material to meet the needs of each unique patient.

New Training Program for the New Requirements of Combat of Tactical Athletes

Actual theaters of operations are complex contexts where soldiers must face different situations, such as symmetrical, asymmetrical, or close quarter combat. The requirements of the actual battlefield are different to the traditional conditioning military training. This new changing scenario produces an activation of the innate fight or flight defense mechanisms with large activations of the anaerobic metabolic pathways and the sympathetic autonomic nervous system. In these scenarios, the anaerobic, aerobic, and strength demands are so specific and the time to improve all training demands in the units is limited. We propose a new training periodization for the military population based on the latest research into the psychophysiological response of soldiers in actual theaters of operations (actual military missions) and actual civilian models of training and periodization to develop a specific, easy, and reliable periodization model for actual tactical athletes. This training intervention was developed in order to improve operational training according to the demands of actual theaters of operations, based on recent research in military and civilian populations. We tried to conduct a proposal that is easy to apply, with minimal use of material different to what could be found in a military base and that could be implemented in a short period of time.

Effect of Increasing Running Cadence on Peak Impact Force in an Outdoor Environment

BACKGROUND

An estimated 56% of recreational runners sustain a running-related injury related to the high impact forces in running. Increasing step frequency (cadence) while maintaining a consistent speed has been shown to be an effective way to lower impact forces which may reduce injury risk.

PURPOSE

To examine effects of increased cadence on peak impact force during running in an outdoor setting. It was hypothesized that as cadence increases, peak force would decrease.

STUDY DESIGN

Repeated measures, quasi-experimental.

METHODS

Peak force and cadence measurements were collected from 15 recreational runners (8 females, 7 males) during two 2.4-mile outdoor runs. Peak force was measured using an insole-based load measuring device. Baseline session run was completed at participant's naturally preferred cadence and cadence session run was completed at a cadence targeted to be 10% greater than baseline. Pace was monitored with a GPS watch. Cadence was cued by an auditory metronome and measured with both GPS watch and insoles. Repeated-measures ANOVA's examined the differences in average peak force, GPS-reported cadence, and insole-reported cadence between mile 1 and mile 2, and across the two cadence conditions.

RESULTS

Cadence differences of 7.3% were observed between baseline and cadence sessions (p<0.001). A concurrent decrease in average peak force of 5.6% was demonstrated during the cadence run (p<0.05). Average cadences measured by GPS watch and insoles were found to be the same at both baseline (p=0.096) and during cadence (p=0.352) sessions.

CONCLUSION

Increasing cadence by an average of 7% in an outdoor setting resulted in a decrease in peak force at two different time points during a 2.4-mile run. Furthermore, using a metronome for in-field cadence manipulation led to a change in cadence. This suggests that a metronome may be an effective tool to manipulate cadence for the purpose of decreasing peak impact force in an outdoor setting.

LEVEL OF EVIDENCE

3b.

Musculoskeletal Injuries in US Air Force Security Forces, January 2009 to December 2018

OBJECTIVE

To determine the incidence, types, and risk factors of musculoskeletal injuries in a military security forces population.

METHODS

Demographic and diagnostic data were retrieved on enlisted US Air Force security forces personnel who served on active duty between January 2009 and December 2018. Incidence rates and ratios were calculated using Poisson regression.

RESULTS

During 251,787 person-years of exposure, 62,489 personnel served on active duty. Of these, 40,771 (65.2%) were diagnosed with at least one musculoskeletal injury. The majority (60.1%) of the 164,078 unique musculoskeletal injuries were inflammation and pain secondary to overuse. After adjusting for other factors, women had a 31% higher injury rate than men, and those who were overweight and obese had 15% and 30% higher rates, respectively, than normal-weight peers.

CONCLUSIONS

Modifiable and non-modifiable factors contribute to musculoskeletal injuries in the security forces career field.

Applying Force Plate Technology to Inform Human Performance Programming in Tactical Populations

Force plate assessments, such as countermovement jumps and isometric mid-thigh pulls, examine performances (e.g., jump height, force, power) and movement strategies (e.g., asymmetries, durations), and are best suited to characterize and monitor physical capabilities, not predict injuries. To begin applying force plate technologies, users must first; (1) develop a data management plan to visualize and capture data over time; (2) select appropriate force plates for their scenario; (3) design appropriate testing protocols to ensure valid and reliable data. Force plate assessments may be added to existing testing, serve as separate testing batteries for annual profile testing to compare individuals and understand initial physical capabilities, or for more frequent testing (i.e., monthly or weekly) to monitor training-related adaptations or neuromuscular fatigue. Although these assessments inform evidence-based program designs, human performance practitioners must understand the considerations for conducting appropriate force plate testing, as well as proper visualizations and management of force plate data. Thus, the aim of this review is to provide evidence-based practices for utilizing force plates in tactical populations (e.g., military, firefighters, police). This includes best practices to implement testing for performance profiling, training adaptations, and monitoring neuromuscular fatigue and force asymmetries. Of note, due to the large amount of force-time metrics to choose from, this article provides general examples of important metrics to monitor and training recommendations based on changes to these force-time metrics, followed by specific examples in three case studies.

Kinetic and Kinematic Analysis of Various Drop Jump Performances in Army Reserve Officer Training Corps Cadets

ABSTRACT

Merrigan, JJ, O'Toole, KB, Wutzke, CJ, and Jones, MT. Kinetic and kinematic analysis of various drop jump performances in army reserve officer training corps cadets. J Strength Cond Res XX(X): 000-000, 2021-The purpose was to examine effects of sex, drop height, and external loads on drop jump mechanics in Reserve Officer Training Corps cadets and whether findings were associated with strength. Males (n = 14) and females (n = 12) completed maximal isokinetic concentric (slow-C and fast-C) and eccentric (slow-E and fast-E) knee extensions and flexions at 60°·s-1 and 180°·s-1. After 72 hours, 3 drop jumps were performed under 3 conditions, (i.e., 30 cm unloaded [30UL], 30 cm loaded 15 kg [30L], and 60 cm unloaded [60UL]). No sex × condition interactions existed for any metric (p > 0.05). The 30L condition resulted in slower eccentric and concentric center of mass (COM) and angular velocities, reduced concentric vertical ground reaction forces (vGRF), and lower jump performances. Although 60UL resulted in greater eccentric COM and angular velocities, peak vGRF, impulse, and rate of force development (p < 0.008), no differences existed in jump performances. Males had faster COM and angular concentric velocities and smaller knee valgus angles, but no different vGRF compared with females. The change in the peak hip angle, because of 60UL, was associated with knee extension eccentric and concentric strength, whereas changes in knee angles were associated with eccentric strength. Likewise, eccentric strength influenced the effects of 30L on landing vGRF more so than concentric strength. Initial strength training is recommended, specifically emphasizing eccentric actions, before performing loaded (15 kg) drop jumps to reduce the increase of landing forces. However, caution may be required when performing drops from 60 cm because of increased forces, although no decline in jump performances were noted.

Dimensionality Reduction Differentiates Sensitive Force-Time Characteristics from Loaded and Unloaded Conditions throughout Competitive Military Training

The purpose was to evaluate neuromuscular fatigue’s effect on unloaded and loaded countermovement jump (CMJ) force-time characteristics during high-intensity tactical training. Eighteen male and sixteen female Marines completed two maximal effort CMJs, in unloaded (PVC pipe) and loaded (10 kg weight vest and 20 kg barbell) conditions, prior to, and 24, 48, and 72 h after starting the 4-day event. The top three variables from three principal components (PC) were analyzed using mixed-effects modeling (PC1—concentric mean power, eccentric peak force, and modified reactive strength index; PC2—countermovement depth, eccentric mean power, and eccentric mean velocity; PC3—braking duration, jump height, peak power). Metrics from PC1 and PC3 were reduced across training and from both loading conditions. Metrics from PC2 were similarly affected by external loading but were less influenced by training-induced fatigue. Jump performances with the barbell and with shallower countermovement depths did not change throughout training. Thus, 20 kg loaded CMJs are stable neuromuscular measures suitable for tracking chronic training adaptations. Monitoring unloaded and 10 kg loaded CMJ performances, along with movement strategies (i.e., countermovement rates and depth), may help identify moments of accumulated fatigue to inform training and recovery adjustments and improve the sustainability of personnel.

The feasibility of implementing an evidence-based physical training program during a Canadian Armed Forces basic infantry course

OBJECTIVES

Determine the feasibility of implementing an evidence-based training program compared to a control during a basic infantry training course, and compare their effectiveness on measures of injuries and associated burdens.

DESIGN

Prospective, cohort, feasibility study.

METHODS

Infantry candidates awaiting course between 01-April-2019 and 31-March-2020 were invited to participate while those releasing from the military, awaiting occupational transfer or having >5 medical employment limitation days were excluded. Consenting participants were allocated to an infantry course prospectively scheduled to host either the evidence-based program or a control. The evidence-based program adapted modified physical training strategies from previous studies reporting reduced injuries in recruits and was supervised by certified fitness professionals, while the control was at the discretion of infantry instructors.

RESULTS

With the exception of intervention duration which was limited due to operational factors, all feasibility outcomes were met including a recruitment rate of 171/203=84.2% and an intervention adherence of 126/144=87.5%. Stakeholders reported that the evidence-based program implementation was feasible, posing a manageable demand on resources without compromising operations. Evidence-based program participants reported 68% fewer overuse musculoskeletal injuries, 296 fewer medical employment limitation days and 11 fewer attritions than control participants.

CONCLUSIONS

An evidence-based training program is feasible to implement on a basic infantry training course, and results in fewer musculoskeletal injuries, medical employment limitation days and attrition. Given these results, this program should be generalizable for a full experimental trial, and may be scaled for intermediate/advanced infantry and/or other combat occupation courses to promote an evolution towards evidence-based training.

The Association Between Poor Sleep and the Incidence of Sport and Physical Training-Related Injuries in Adult Athletic Populations: A Systematic Review

BACKGROUND

The importance of achieving an adequate amount of sleep to optimize health and athletic performance is well recognized. Yet, a systematic evidence compilation of the risk for sport-related injury in adult athletic populations due to poor sleep does not exist.

OBJECTIVE

To examine the association between poor sleep and sport and physical training-related injuries in adult athletic populations.

DATA SOURCES

Electronic databases were searched using keywords relevant to sleep quantity and quality, and musculoskeletal injury and sport-related concussion (SRC).

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies were included in this systematic review if they were comprised of adult athletic populations, reported measures of sleep quantity or quality, followed participants prospectively for injury, and reported an association between sleep and incidence of sport or physical training-related injury.

STUDY APPRAISAL

The methodological quality of each study was assessed using the Newcastle-Ottawa Scale for Cohort Studies.

RESULTS

From our review of 12 prospective cohort studies, we found limited evidence supporting an association between poor sleep and injury in adult athletic populations. Specifically, there is (a) insufficient evidence supporting the associations between poor sleep and increased risk of injury in specific groups of athletic adults, including professional or elite athletes, collegiate athletes, elite or collegiate dancers, and endurance sport athletes; and (b) limited evidence of an association between poor sleep and increased risk of SRC in collegiate athletes.

CONCLUSIONS

The current evidence does not support poor sleep as an independent risk factor for increased risk of sport or physical training-related injuries in adult athletic populations. Given the methodological heterogeneity and limitations across previous studies, more prospective studies are required to determine the association between sleep and injury in this population.

A novel prophylactic Chinese parachute ankle brace

Background

The objective is to compare the effects of a self-designed and self-manufactured novel prophylactic ankle brace [Chinese parachute ankle brace (CPAB)] and two ordinary ankle braces on the ankle joint during a half-squat parachute landing (HSPL) via biomechanical assessment.

Methods

Twenty elite paratroopers were in four different conditions: no brace, elastic brace, semi-rigid brace, and CPAB. Each participant was instructed to jump off a platform with three different heights, 40, 80, and 120 cm, and land on the force plate in a half-squat posture. The vertical ground reaction forces (vGRFs), joint angles, moments, powers, and works were calculated. After the experiment, every participant completed the questionnaires designed for this study.

Results

Increasing the dropping height increased all of the parameters significantly (P<0.01), except for time to peak vGRF (T-PvGRF). Applying three braces can all slightly increase vGRF (P=0.237) and reduce T-PvGRF by 6–10 ms, as well as decrease the joint angles, velocities, and moments on the sagittal and coronal planes. Wearing CPAB and a semi-rigid brace more efficiently restricted dorsiflexion and inversion (P<0.05), and they both significantly reduced ankle work (t=5.107, P<0.01; t=3.331, P<0.01) and peak power (t=7.237, P<0.01; t=6.711, P<0.01) at 120 cm. The total scores from low-to-high were semi-rigid brace (19.20±2.99), elastic brace (21.91±3.25), and CPAB (23.37±3.08).

Conclusions

The CPAB was more effective at restricting ankle joint motion on the coronal and sagittal planes than the other two prophylactic ankle braces. Therefore, the CPAB had the advantages of a novel appearance, high efficiency, and superior comfort, providing a reliable choice for parachute jumping and training in China.

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.

Characterization of Limited Duty Neuromusculoskeletal Injuries and Return to Duty Times in the U.S. Army During 2017-2018

INTRODUCTION

Neuromusculoskeletal injuries (MSKI) are the leading cause of medical encounters, lost or limited duty days, medical evacuations, and disability in the U.S. Army. In the U.S. Army, objective MSKI incidence rate metrics can be determined through medical encounter data (M2SKIs) with International Classification of Diseases (ICD) 9 and ICD 10 codes or through documented limited duty profiles (LDPs) documenting time-loss MSKI (TLMSKI). The purpose of the current study was to characterize the population incidence of TLMSKIs among U.S. Army soldiers.

MATERIALS AND METHODS

This study was approved by the Medical Research and Development Command's Institutional Review Board. This was a retrospective population-level study. The U.S. Army's eProfile system was utilized to characterize all LDPs issued during 2017-2018 and to describe the body regions injured and activities associated with these TLMSKIs.

RESULTS

The incidence rate of TLMSKIs was found to be 44 and 40 TLMSKI/100 soldier-years for 2017 and 2018, respectively, which is lower than previously published incidence rates using MSKI receiving medical care. Approximately one quarter of the total active duty Army population in 2017 and 2018 recorded limited duty injuries, where those to the ankle/foot region resulted in the most LDPs and those to the knee resulted in the most lost duty days. The majority of all TLMSKIs were associated with fitness training-related activities.

CONCLUSION

This descriptive study is the first to present the U.S. Army population rates for MSKIs that result in LDPs, representing key time losses when soldiers cannot participate in their military occupational and physical training tasks. This study utilizes the LDP system to calculate limited duty days instead of attempting to estimate this information from other means. The eProfile system is limited in that it combines body regions such as ankle/foot and does not allow isolation of ankle or foot independently. It is recommended that research and training programs target the identification, development, and validation of effective and scaleable strategies to maximize performance without severely reducing combat effectiveness because of training TLMSKIs.

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.

Identifying Reliable and Relatable Force-Time Metrics in Athletes-Considerations for the Isometric Mid-Thigh Pull and Countermovement Jump

The purpose of this study was to evaluate intrasession reliability of countermovement jump (CMJ) and isometric mid-thigh pull (IMTP) force-time characteristics, as well as relationships between CMJ and IMTP metrics. Division I sport and club athletes (n = 112) completed two maximal effort CMJ and IMTP trials, in that order, on force plates. Relative and absolute reliability were assessed using intraclass correlation coefficients (ICCs) > 0.80 and coefficients of variation (CVs) < 10%. Intrasession reliability was acceptable for the majority of the CMJ force-time metrics except for concentric rate of force development (RFD), eccentric impulse and RFD, and lower limb stiffness. The IMTP's time to peak force, instantaneous force at 150 ms, instantaneous net force, and RFD measures were not reliable. Statistically significant weak to moderate relationships (r = 0.20-0.46) existed between allometrically scaled CMJ and IMTP metrics, with the exception of CMJ eccentric mean power not being related with IMTP performances. A majority of CMJ and IMTP metrics met acceptable reliability standards, except RFD measures which should be used with caution. Provided CMJs and IMTPs are indicative of distinct physical fitness capabilities, it is suggested to monitor athlete performance in both tests via changes in those variables that demonstrate the greatest degree of reliability.

Sex and Stride Impact Joint Stiffness During Loaded Running

This study determined changes in lower limb joint stiffness when running with body-borne load, and whether they differ with stride or sex. Twenty males and 16 females had joint stiffness quantified when running (4.0 m/s) with body-borne load (20, 25, 30, and 35 kg) and 3 stride lengths (preferred or 15% longer and shorter). Lower limb joint stiffness, flexion range of motion (RoM), and peak flexion moment were submitted to a mixed-model analysis of variance. Knee and ankle stiffness increased 19% and 6% with load (P < .001, P = .049), but decreased 8% and 6% as stride lengthened (P = .004, P < .001). Decreased knee RoM (P < .001, 0.9°-2.7°) and increased knee (P = .007, up to 0.12 N.m/kg.m) and ankle (P = .013, up to 0.03 N.m/kg.m) flexion moment may stiffen joints with load. Greater knee (P < .001, 4.7°-5.4°) and ankle (P < .001, 2.6°-7.2°) flexion RoM may increase joint compliance with longer strides. Females exhibited 15% stiffer knee (P = .025) from larger reductions in knee RoM (4.3°-5.4°) with load than males (P < .004). Stiffer lower limb joints may elevate injury risk while running with load, especially for females.

Monitoring Neuromuscular Performance in Military Personnel

A necessarily high standard for physical readiness in tactical environments is often accompanied by high incidences of injury due to overaccumulations of neuromuscular fatigue (NMF). To account for instances of overtraining stimulated by NMF, close monitoring of neuromuscular performance is warranted. Previously validated tests, such as the countermovement jump, are useful means for monitoring performance adaptations, resiliency to fatigue, and risk for injury. Performing such tests on force plates provides an understanding of the movement strategy used to obtain the resulting outcome (e.g., jump height). Further, force plates afford numerous objective tests that are valid and reliable for monitoring upper and lower extremity muscular strength and power (thus sensitive to NMF) with less fatiguing and safer methods than traditional one-repetition maximum assessments. Force plates provide numerous software and testing application options that can be applied to military's training but, to be effective, requires the practitioners to have sufficient knowledge of their functions. Therefore, this review aims to explain the functions of force plate testing as well as current best practices for utilizing force plates in military settings and disseminate protocols for valid and reliable testing to collect key variables that translate to physical performance capacities.

Conditional Recommendations for Specific Dietary Ingredients as an Approach to Chronic Musculoskeletal Pain: Evidence-Based Decision Aid for Health Care Providers, Participants, and Policy Makers

OBJECTIVE

Approximately 55-76% of Service members use dietary supplements for various reasons; although such use has become popular for a wide range of pain conditions, decisions to use supplements are often driven by information that is not evidence-based. This work evaluates whether the current research on dietary ingredients for chronic musculoskeletal pain provides sufficient evidence to inform decisions for practice and self-care, specifically for Special Operations Forces personnel.

METHODS

A steering committee convened to develop research questions and factors required for decision-making. Key databases were searched through August 2016. Eligible systematic reviews and randomized controlled trials were assessed for methodological quality. Meta-analysis was applied where feasible. GRADE was used to determine confidence in the effect estimates. A decision table was constructed to make evidence-informed judgments across factors required for decision-making, and recommendations were made for practice and self-care use.

RESULTS

Nineteen dietary ingredients were included. Conditional evidence-based recommendations were made for the use of avocado soybean unsaponifiables, capsaicin, curcuma, ginger, glucosamine, melatonin, polyunsaturated fatty acids, and vitamin D. In these cases, desirable effects outweighed undesirable effects, but there was uncertainty about the trade-offs, either because the evidence was low quality or because benefits and downsides were closely balanced.

CONCLUSIONS

The evidence showed that certain dietary ingredients, when taken as part of a balanced diet and/or as a supplement (e.g., pill, tablet, capsule, cream), may alleviate musculoskeletal pain with no to minimal risk of harm. This finding emphasizes and reinforces the critical importance of shared decision-making between Operators and their health care providers.

Dietary Ingredients as an Alternative Approach for Mitigating Chronic Musculoskeletal Pain: Evidence-Based Recommendations for Practice and Research in the Military

OBJECTIVE

Approximately 55-76% of Service members use dietary supplements for various reasons, including pain and related outcomes. This work evaluates current research on dietary ingredients for chronic musculoskeletal pain to inform decisions for practice and self-care, specifically for Special Operations Forces personnel.

METHODS

A steering committee convened to develop research questions and factors required for decision-making. Key databases were searched through August 2016. Eligible systematic reviews and randomized controlled trials were assessed for methodological quality. Meta-analysis was applied where feasible. GRADE was used to determine confidence in the effect estimates. The committee made evidence-informed judgments and recommendations for practice and self-care use.

RESULTS

Nineteen eligible dietary ingredients were assessed for quality, efficacy, and safety. Avocado soybean unsaponifiables, capsaicin, curcuma, ginger (as a food source), glucosamine, melatonin, polyunsaturated fatty acids, and vitamin D were conditionally recommended as their benefits outweighed risks, but there was still some uncertainty about the trade-offs. No recommendations were made for boswellia, ginger (as a dietary supplement), rose hip, or s-adenosyl-L-methionine. Recommendations were made against the use of collagen, creatine, devil's claw, l-carnitine, methylsulfonylmethane, pycnogenol, willow bark extract, and vitamin E. Research priorities were developed to address gaps precluding stronger recommendations.

CONCLUSIONS

Currently the scientific evidence is insufficiently robust to establish definitive clinical practice guidelines, but processes could be established to track the impact of these ingredients. Until then, providers have the evidence needed to make informed decisions about the safe use of these dietary ingredients, and future research can address existing gaps.

Exercise Programs to Reduce the Risk of Musculoskeletal Injuries in Military Personnel: A Systematic Review and Meta-Analysis

Objective

To evaluate the effect of exercise programs on reduction of musculoskeletal injury (MSI) risk in military populations.

Design

Systematic review and meta‐analysis.

Literature Survey

A database search was conducted in PubMed/MEDLINE, EMBASE, Cochrane Library, CINAHL, SPORTdiscus, WHO International Clinical Trials Registry Platform Search Portal, Open Gray, National Technical Reports Library, and reference lists of included articles up to July 2019. Randomized and cluster‐randomized controlled trials evaluating exercise programs as preventive interventions for MSIs in armed forces compared to other exercise programs or to usual practice were eligible for inclusion.

Methodology

Two authors independently assessed risk of bias and extracted data. Data were adjusted for clustering if necessary and pooled using the random‐effects model when appropriate.

Synthesis

We included 15 trials in this review, with a total number of 14 370 participants. None of the included trials appeared to be free of any risk of bias. Meta‐analysis and Grading of Recommendations, Assessment, Development and Evaluations (GRADE) assessment could be performed for static stretching compared to no stretching (3532 participants), showing low quality of evidence indicating no favorable effect of stretching. Gait retraining, an anterior knee‐pain targeted program, and resistance exercises showed cautious favorable effects on reducing injury risk in military personnel.

Conclusion

The current evidence base for exercise‐based MSI prevention strategies in the military is of low quality. Areas worthy of further exploration include the effects of gait retraining, anterior knee‐pain targeted programs, agility training, and resistance training programs, on medial tibial stress syndrome incidence, anterior knee pain incidence, attrition due to injuries and any type of MSI, respectively.

Epidemiology and Financial Burden of Musculoskeletal Injuries as the Leading Health Problem in the Military

INTRODUCTION

Musculoskeletal injuries (MSIs) have direct impact on occupational readiness and task performance in military populations. Until this date, no epidemiologic data have been published concerning MSI incidence in the Netherlands Armed Forces (NAF). The aim of this study was to assess the MSI incidence and related costs in the NAF.

METHODS

In this descriptive epidemiologic study, we collected injury surveillance data from the electronic patient records of multiple military units of the NAF. Using data of all new consultations with a military physician from January 1, 2014 to December 31, 2016, we calculated MSI incidence rates per 100 person-years, with a 95% confidence interval (CI). Physician care costs were determined based on the number of physician consults and the charge per appointment. We used two methods to determine productivity costs; the top-down microcosting method and the friction cost method.

RESULTS

Our study sample included 22% (n = 8,847) of the total NAF population of 2016 (n =40,178). In this sample, consultations of MSIs accounted for 23.2% (n = 7,815) of all new consultations (n = 33,666). MSI incidence rates per unit ranged from 12.5 to53.3 per 100 person-years. In the total sample, MSI incidence rates were highest in the back (6.73, 95% CI 6.39-7.10), knee (5.04, 95% CI 4.74-5.35), and foot (4.79, 95% CI 4.50-5.10). The estimated costs for physician visits for MSIs in our sample were €0.69 million. Limited duty days accounted for €1.10 million productivity costs using top-down microcosting method.

CONCLUSION

Our study provided evidence that MSIs result in substantial financial burden. Injuries of the back, knee, and foot account for the majority of demands on curative care for MSIs.

Risk factors for injury among military working dogs deployed to Iraq

There is limited literature concerning the types of injuries that military working dogs (MWDs) face while in a deployed theater of operations and associated risk factors. To summarize injuries and identify injury risk factors in MWDs during their first deployments to Iraq, demographic and medical data were collected for 794 MWDs from the U.S. Army, Air Force, Navy, and Marine Corps that deployed to Iraq between March 20, 2003 and December 31, 2007. Sixty-two percent (n = 490) had a medical encounter during deployment. Injuries were categorized as traumatic or musculoskeletal. MWD demographics, characteristics, and injury types were summarized. Injury risk factors were assessed using multivariable logistic regression. A majority of the population were German Shepherds (56 %), intact males (49 %), and dogs certified in both patrol and explosives detection (73 %). During their first deployment to Iraq, 20 % (n = 156) experienced an injury. Risk factors included breed, age, and occupational certification. Belgian Malinois and Labrador Retriever dogs had greater odds of injury compared to German Shepherds (p = 0.04 and p = 0.02) and the oldest MWDs had about a 50 % higher risk of injury compared to the youngest (p = 0.01), especially for musculoskeletal injuries. MWDs with Specialized Search certification were at increased injury risk (p = 0.02). Training, equipment, and supplies for veterinary service personnel, MWD handlers, and MWDs should be tailored with consideration of the injury risks of the MWD population. Further study is needed to investigate chronic injuries in military working dogs to better understand causation and prevention.

Dynamic Postural Stability in Active, Adolescent Males Following Repeated Bouts of Aerobic Exercise in Hot and Temperate Environments: A Pilot Study

Introduction

Proper jump-landing neuromuscular control is crucial in mitigating lower-extremity musculoskeletal injuries. The presence of fatigue, especially in extreme environments, may degrade dynamic postural stability (DPS) and result in lower-extremity injuries. This study aimed to evaluate the influence of moderate intensity exercise in hot (HOT) and temperate (TEMP) ambient temperatures and residual effects of a previous bout on DPS during a single-legged jump-landing. It was hypothesized that the participants would display worse DPS after HOT compared to TEMP.

Methods

Six recreationally active young males (16.8 ± 0.7 year, 1.88 ± 0.12 m, 83.8 ± 19.8 kg) completed two, 60-minute bouts of exercise with 60 minutes of rest between bouts in both HOT (35°C) and TEMP (22.2°C). Heart rate and core body temperature (T_c) were monitored continuously, and DPS was assessed before and after each bout.

Results

The DPS time and condition effects were not identified (p > 0.05), but HOT elicited some notable (d > 0.20) increases in heart rate, T_c, and DPS compared to TEMP.

Conclusions

The DPS decrements varied between subjects suggesting individual-specific etiology. Repeated bouts of exercise in HOT may place an individual at a greater risk for injury than TEMP if proper prevention strategies are not used.

Relationship between individual payload weight and spondylolysis incidence in Turkish land forces

OBJECTIVEThe aim of this study was to investigate the relationship between lumbar spondylolysis and payload weight between different combat units of Turkish land forces (TLF).METHODThe authors reviewed clinical and radiological data of the military personnel with low-back pain (LBP) admitted to their clinic between July 2017 and July 2018. Age, BMI, average payload weight, and military service unit were recorded. CT scans were evaluated for pars interarticularis fractures and spondylolisthesis, whereas MRI studies were evaluated for spondylolisthesis, Modic-type endplate changes, or signal loss on T2-weighted images compatible with disc degeneration.RESULTFollowing exclusion, a total of 642 all-male military personnel were included. Of these personnel, 122 were commandos, 435 were infantry, and 85 were serving in the artillery units. Bilateral pars interarticularis fracture was noted in 42 commandos (34.42%) and 2 infantrymen (0.45%). There was no spondylolysis in the artillery units. There was no multiple-level spondylolysis and the most common level of spondylolysis was L5. Commandos had a significantly higher incidence of spondylolysis and more average payload weight (p < 0.001). Twelve patients (27.2%) with spondylolysis had accompanying MRI pathologies at the same level, whereas 32 patients (72.7%) had no accompanying MRI pathologies.CONCLUSIONSIncreased payload weight in military personnel is associated with spondylolysis, and commandos in the TLF have significantly heavier payloads, which causes an increased rate of spondylolysis compared to other units. Additionally, spondylolysis without adjacent-level changes on MRI could be undiagnosed. LBP in active military personnel who have a history of carrying heavy payloads should be evaluated extensively with both MRI and CT scans.

Systematic Review of the Association Between Physical Fitness and Musculoskeletal Injury Risk: Part 3-Flexibility, Power, Speed, Balance, and Agility

de la Motte, SJ, Lisman, P, Gribbin, TC, Murphy, K, and Deuster, PA. Systematic review of the association between physical fitness and musculoskeletal injury risk: part 3-flexibility, power, speed, balance, and agility. J Strength Cond Res 33(6): 1723-1735, 2019-We performed a systematic review and evaluation of the existing scientific literature on the association between flexibility, power, speed, balance, and agility, and musculoskeletal injury (MSK-I) risk in military and civilian populations. MEDLINE, EBSCO, EMBASE, and the Defense Technical Information Center were searched for original studies published from 1970 to 2015 that examined associations between these physical fitness measures (flexibility, power, speed, balance, and agility) and MSK-I. Methodological quality and strength of the evidence were determined after criteria adapted from previously published systematic reviews. Twenty-seven of 4,229 citations met our inclusion criteria. Primary findings indicate that there is (a) moderate evidence that hamstring flexibility, as measured by performance on a sit-and-reach test or active straight leg raise test assessed with goniometry, and ankle flexibility, assessed with goniometry, are associated with MSK-I risk; (b) moderate evidence that lower body power, as measured by performance on a standing broad jump or vertical jump with no countermovement, is associated with MSK-I risk; (c) moderate evidence that slow sprint speed is associated with MSK-I risk; (d) moderate evidence that poor performance on a single-leg balance test is associated with increased risk for ankle sprain; and (e) insufficient evidence that agility is associated with MSK-I risk. Several measures of flexibility, power, speed, and balance are risk factors for training-related MSK-I in military and civilian athletic populations. Importantly, these findings can be useful for military, first responder, and athletic communities who are seeking evidence-based metrics for assessing or stratifying populations for risk of MSK-I.

Dietary Ingredients Requiring Further Research Before Evidence-Based Recommendations Can Be Made for Their Use as an Approach to Mitigating Pain

OBJECTIVE

Approximately 55-76% of Service members use dietary supplements for various reasons; although such use has become popular, decisions are often driven by information that is not evidence-based. This work evaluates whether current research on dietary ingredients for chronic musculoskeletal pain provides sufficient evidence to inform decisions for practice and self-care, specifically for Special Operations Forces personnel.

METHODS

A steering committee convened to develop research questions and factors required for decision-making. Key databases were searched through August 2016. Eligible systematic reviews and randomized controlled trials were assessed for methodological quality. Meta-analysis was applied where feasible. Grading of Recommendations, Assessment, Development and Evaluation was used to determine confidence in the effect estimates. The committee used a decision table to make evidence-informed judgments across decision-making factors and recommendations for practice and self-care use.

RESULTS

Nineteen dietary ingredients were assessed. No recommendations were given for boswellia, ginger, rose hip, or s-adenosyl-L-methionine (SAMe); specifically, although ginger can be obtained via food, no recommendation is provided for use as a supplement due to unclear research. Further, there were insufficient strong research on boswellia and SAMe and possible compliance issues (i.e., high number of capsules required daily) associated with rose hip.

CONCLUSIONS

No recommendations were made when the evidence was low quality or trade-offs were so closely balanced that any recommendation would be too speculative. Research recommendations are provided to enhance the quality and body of evidence for the most promising ingredients. Clinicians and those with chronic pain can rely on evidence-based recommendations to inform their decisions.

Overuse Injuries in the IDF's Combat Training Units: Rates, Types, and Mechanisms of Injury

Introduction

Overuse injuries are responsible for most lost training days and attrition from combat training in the Israeli Defense Forces (IDF) as in armies around the world. The purpose of this study is to understand the rates, types, and mechanism of occurrence of overuse injuries in the IDF in order to provide the IDF's commanders a detailed updated situation report in order to enable commanders decision-making, prevention policy, and further research of this highly significant military public health issue.

Methods

A cross-sectional study including 20,000 soldiers recruited to combat units during the year of 2013 was performed. Most of the data were collected from the IDF's computerized medical consultation records package. Descriptive statistics (percent, mean, standard deviation, and median) were used in order to express results. The study was approved by the IDF's institutional review board.

Results

The overall injury rate was 24.5%. The total number of injuries was 6,393 with an average of 1.32 ± 0.22 injuries per injured soldier. The injury rate was 18.4% in the infantry units and 36.1% in non-infantry units. Of all injuries, 87% occurred in the lower back and lower limb regions. The most frequent injury sites were the calf and ankle (34%), the knee region (22%), and the lower back (19%). Of all injuries, 74% occurred during running (45%) or long-distance walking (29%). The average lost training days due to injuries was 9 d per soldier and 6.5 d per injury. The total number of stress fractures was 494-2.5% of all soldiers (four fractures per 100 person years). The calf and ankle region was the most frequent site of stress fractures and accounted for 84% of all stress fractures, the vast majority of them (95%) were fractures of the distal tibia. The average number of lost training days due to stress fractures was 16 ± 6.1 per fracture.

Conclusions

As in other armies around the world, overuse injuries in the IDF are a major public health problem and poses a significant challenge to the IDF's commanders and the medical corps policy leaders. Further studies should be performed in order to identify the risk factors for these injuries especially in the lower back and the lower limb regions as part of the effort to try and reduce the rates of these injuries as much as possible. This study emphasizes the need for a continuous surveillance and monitoring system for overuse injuries as a significant and integral component of any intervention plan in the domain of overuse injuries.