Model for Musculoskeletal Injury Risk Factors Among US Army Basic Combat Trainees

Pregnancy is characterized by hormone changes that could alter musculoskeletal (MSK) properties and temporarily increase soft tissue injury risk. Although the prevalence of MSK injuries in pregnancy has not yet proven itself to be a widespread problem, indirect evidence indicates an uptake in the prevalence of strength training and vigorous-intensity activity during pregnancy, which may result in increased MSK injury incidence. Combining this evidence with the association between sex hormones and MSK injury risk, we recognize the potential importance of this research area and believe the (prospective) examination of connective tissue properties in pregnancy is appropriate. Given the dearth of information on MSK adaptations to pregnancy, we present a variety of morphological, mechanical, and functional tendon data from two consecutive pregnancies in one woman as a means of highlighting this under researched topic. These data may be representative of the general pregnant population, or it may be highly individualized. More research is required for a better understanding of MSK adaptation and injury risk during and after pregnancy.NEW & NOTEWORTHY The literature is sparse on the topic of MSK adaptation and injury risk during pregnancy, hence we present this case study as means of highlighting an area of research that is of increasing importance. Here, we present a case study concerning the morphological, mechanical, and functional adaptation of load-bearing tendons during this unique period. We also discuss different rationales, study considerations, and future directions for continuing this research theme.

2111 Past anecdotal reports suggested that injury incidence increased immediately following foot marches (FM) in US Army Basic Combat Training (BCT). To mitigate injuries, the Army instituted a progressive foot marching schedule; recruits begin with a 3 km foot march and progressively increase the distance on 5 subsequent marches until they complete a 15 km foot march by the end of BCT. PURPOSE: To determine if injury incidence increases following foot marches in BCT. METHODS: Participants were 930 men and 622 women in BCT. As part of standard protocol, trainees completed foot marches at a pace of about 4.8 km/h in military uniform and while carrying a load (equipment and rucksack) of about 20 kg. The third (FM3) and fourth (FM4) foot marches (8 and 10 km, respectively) were selected for review since the last 2 foot marches were associated with a very physically demanding field exercise. Injuries were obtained from a medical surveillance system that captured trainees' visits to the medical treatment clinic. The McNemar test for related samples was used to examine the distribution of injuries before and after the march. RESULTS: Among women, injury incidence was higher in the 3 days prior to FM3 (before = 4.0 injured/100 trainees, after = 1.3 injured/100 trainees, p<0.01) but injury incidence before and after FM4 was similar (before = 4.0 injured/100 trainees after = 3.9 injured/100 trainees, p = 1.00). There was no significant difference in pre- and post-FM injury incidence among men for FM3 (before = 1.7 injuries/100 trainees, after = 1.3 injuries/100 trainees, p = 0.56) or FM4 (before = 2.4 injuries/100 trainees, after = 1.6 injuries/100 trainees, p = 0.30). Examination of training schedules suggested that injury incidence prior to FM4 may have been confounded by participation in the confidence course and rappelling tower. CONCLUSION: With the way BCT is currently structured, FM do not appear to be associated with higher injury incidence in the period immediately following the march. It is dif. cult to isolate the influence of specific BCT events on injuries since trainees perform many physically demanding tasks in close proximity.

Insufficient sleep is a common challenge in the military. Rigorous training phases, such as Basic Combat Training (BCT), are often associated with changes in habitual sleep characteristics. In a recent study, trainees reported decreases in sleep quality and habitual sleep duration during BCT, with the majority (~76%) reporting <7 hours of sleep per night, which is less than the general recommendation for adults. Poor sleep characteristics are associated with higher BMI, increased body fat (BF), and decreased lean mass (LM). While previous work demonstrates that BCT favorably alters body composition, the influence of sleep characteristics on body composition changes during BCT are unknown. PURPOSE: To understand relationships between sleep characteristics and changes in body composition during BCT. METHODS: Participants were 1608 trainees (female = 553), mean age 20.83 ± 3.7 years (range 17-39). During the first (T1) and final (T2) weeks of BCT, trainees completed the Pittsburgh Sleep Quality Index, which measures sleep quality and duration, and had their body composition assessed using dual-energy X-ray absorptiometry. Linear mixed models were used to examine the relationships between sleep changes and body composition changes. RESULTS: Findings are presented in Table 1. Trainees who reported a decrease in sleep duration from T1 to T2 lost less BF than those who reported an increase or no change in sleep duration across BCT. Changes in sleep quality were not related to changes in fat mass. Neither changes in sleep duration nor quality were related to changes in lean mass. CONCLUSION: Healthy body composition is associated with improved physical performance, fewer musculoskeletal injuries, and lower all-cause discharge from military service. This analysis provides important evidence that encouraging healthy sleep habits during BCT may facilitate healthy body composition changes during training, which can positively influence overall training outcomes. - Table 1 Δ Lean Mass (kg) Δ Fat Mass (kg) β (95%CI) P β (95%CI) P Change in Sleep Duration Increase -0.021 (-0.293, 0.251) 0.88a 0.210 (-0.203, 0.624) 0.319a No Change - - - - Decrease 0.170 (-0.036, 0.376) 0.106a 0.399 (0.086, 0.712) 0.013a Change in Sleep Quality Increase -0.101 (-0.369, 0.167) 0.46b -0.168 (-0.575, 0.239) 0.418b No Change - - - - Decrease -0.139 (-0.348, 0.070) 0.192b -0.145 (-0.463, 0.172) 0.370b

U.S. Army Basic Combat Training (BCT) prepares new recruits to meet soldier physical demands. It also serves as a model of physical changes in healthy young nonobese women and men during an intensive 10-week training program without diet restriction. In this prospective observational study, we quantified the changes in lean mass and body fat induced by BCT in a large sample of men and women undergoing the same physical training program. Young women (n = 573) and men (n = 1071) meeting Army health and fitness recruitment standards volunteered to provide DXA-derived body composition data at the beginning and end of BCT. During BCT, there was no change in body mass in women and a 1.7-kg loss in men. Relative body fat (%BF) declined by an average of 4.0 ± 2.4 and 3.4 ± 2.8 percentage points (±SD) for women and men, respectively. The greatest predictor of change in %BF during BCT for both sexes was %BF at the beginning of training. Women and men gained an average 2.7 ± 1.6 kg and 1.7 ± 2.0 kg of lean mass during BCT. Army BCT produced significant effects on body composition despite minimal changes in total body mass. These findings demonstrate the ability of a 10-week sex-integrated physical training program to positively alter body composition profiles of young adults.

Musculoskeletal injuries (MSI) are common in racehorses and have been of increasing concern in horses travelling internationally to compete. Understanding the differences in bone turnover between local horses and international horses following long-distance air transportation may inform MSI prevention strategies. To understand the differences in bone turnover markers and risk of MSI between local horses and international horses following long-distance air transportation. Prospective cohort. The concentrations of bone turnover markers (OCN and CTXI), markers of stress (cortisol), inflammation (serum amyloid A) and circadian rhythm (melatonin), and bisphosphonates were determined in blood samples collected twice (14-17 days apart), from horses following international travel (n = 69), and from local horses (n = 79). The associations between markers, long-distance travel and MSI were determined using multivariable generalised linear regression models. Within 3-5 days post-transport, concentrations of cortisol in international horses were higher than those of local horses (main effect, Coef. 0.39; 95% CI 0.24, 0.54; p < 0.001) but they decreased and were not different to those of local horses at the second timepoint (interaction effect, Coef. -0.27; 95% CI -0.46, -0.07; p = 0.007). After adjusting for age and sex, OCN and CTXI were not significantly different between international and local horses; however, OCN was lower in international horses at timepoint 2 (interaction effect, Coef. -0.16; 95% CI -0.31, -0.01; p = 0.043). The prevalence of MSI was higher in the international (26%; 95% CI 16, 38%) compared with local horses (8%; 95% CI 3, 16%; p < 0.001), with all severe MSI sustained by the international horses. At the second timepoint compared with the first timepoint post-transport, cortisol remained high or increased (interaction effect, Coef. 0.43; 95% CI 0.24, 0.61; p < 0.001) and OCN increased (interaction effect, Coef. 0.26; 95% CI 0.08, 0.44; p = 0.006) in the horses that sustained severe MSI. Horse population and racing career parameters differed between groups. Bone turnover markers have low sensitivity to detect local bone changes. Most horses showed minimal effects of long-distance air transport within 2 weeks relative to local horses as assessed by stress and bone turnover markers. Screening for persistent high cortisol and evidence of net bone formation after long-distance air transportation may help to identify racehorses at high risk of catastrophic MSI.

Basic trainees at Fort Jackson, South Carolina, who were unable to continue basic combat training (BCT) because of a serious injury were assigned to the Physical Training and Rehabilitation Program (PTRP). Between January 3, 1998 and July 24, 2001, 4258 trainees were assigned to the PTRP. Using a retrospective cohort study design, return to training and BCT graduation rates were evaluated. PTRP graduates were compared with matched non-PTRP graduates for 2-year retention in the Army. More PTRP women than men were discharged from the PTRP (60% and 48%, respectively, p < 0.01). Of PTRP trainees returning to BCT, 10% and 12% of men and women, respectively, were discharged from the Army compared with overall Fort Jackson discharge rates of 9% and 15% for men and women, respectively. Comparing PTRP graduates to matched non-PTRP graduates, there were no differences in 2-year retention for men (14.9% and 14.7%, respectively; p = 0.93) or women (26.6% and 30.1%, respectively; p = 0.19). Despite the high discharge rate in the PTRP, the BCT discharge rate for trainees who successfully rehabilitated was similar to the overall discharge rate at Fort Jackson. The 2-year retention in service for PTRP trainees who graduated from BCT was similar to that of non-PTRP trainees.

Background: Musculoskeletal injuries have a substantial impact on athletes, affecting sports performance and increasing the risk of future musculoskeletal disorders (e.g., osteoarthritis). Injury prevention programs are essential to reduce the risk of sport-related injuries and meta-analyses can provide a large amount of information in a single article. Objective: To summarize the pooled effects of injury prevention programs focused on any form of physical exercise in the incidence and risk of musculoskeletal injuries and reinjuries by sports and musculoskeletal body regions. Methods: The CINAHL (via EBSCOhost), Embase (via Elsevier), Epistemonikos, PubMed, Scopus, SPORTDiscus (via EBSCOhost), and the Cochrane Library e-databases were searched from inception to 7 October 2024. Systematic reviews with meta-analyses of randomized clinical trials were considered. The methodological quality of systematic reviews was assessed with AMSTAR 2. The degree of overlap between meta-analyses of interest was calculated. Results: Fourteen systematic reviews were included. Thirteen of these reviews were focused on soccer. Overall, meta-analyses including a specific injury prevention program (FIFA 11+ and FIFA 11+ kids) found that these programs may reduce the risk of musculoskeletal injuries among soccer players. Concretely, FIFA 11+ may reduce the risk of ankle, knee, hip/groin, and hamstring injuries, whereas FIFA 11+ kids may decrease the risk of ankle and knee injuries. Conclusions: FIFA 11+ and FIFA 11+ kids may reduce the risk of sports musculoskeletal injuries, mainly in the lower limbs. However, many clinical and methodological issues (e.g., the lack of meta-analyses in many types of sports) were discussed and highlighted the difficulty of making robust clinical recommendations with the current data.

Musculoskeletal injuries (MSKI) are one of the biggest challenges for military services globally, contributing to substantial financial burdens and lost training and working days. Effective evidence-based intervention strategies are essential...

Effect of a Basic Training Nicotine-Free Policy on Soldiers in the United States Army

The force and effort required to play a percussion instrument can cause musculoskeletal issues in percussionists (PRMDs). India's most popular percussion instrument is the tabla. The aim of the study was to assess the risk of upper limb musculoskeletal disorders among table players. Method: This cross-sectional study was conducted on seventy-six amateur table players, who were between the age group of 18 to 25 years. The posture of amateur table players and the risk of musculoskeletal injury among them was assessed by using Rapid Upper Limb Assessment (RULA) scale. Result: Assessment of posture while playing tabla by using RULA scale shows that 25.39 % players were at a low risk of musculoskeletal injury, 71.42% players were at a medium risk of musculoskeletal injury and 3.17% were at high risk of musculoskeletal injury. The majority of musculoskeletal pains were in the shoulder and wrist joint. Conclusion: The study shows that the tabla players are at a risk of musculoskeletal injuries and early preventive measures should be implemented to prevent long term complications of wrong posture while playing tabla.

A control group (CG, n = 1,138) that implemented a traditional Basic Combat Training (BCT) physical training (PT) program was compared to an evaluation group (EG, n = 829) that implemented a PT program newly designed for BCT. The Army Physical Fitness Test (APFT) was taken at various points in the PT program, and injuries were obtained from a medical surveillance system. After 9 weeks of training, the proportion failing the APFT was lower in the EG than in the CG (1.7 vs. 3.3%, p = 0.03). After adjustment for initial fitness levels, age, and body mass index, the relative risk of an injury in the CG was 1.6 (95% confidence interval [CI] 51.2–2.0) and 1.5 (95% CI = 1.2–1.8) times higher than in the EG for men and women, respectively. The newly designed PT program resulted in higher fitness test pass rates and lower injury rates compared to a traditional BCT physical training program.

Background:Markerless motion capture (MMC) systems used to screen for musculoskeletal injury (MSKI) risk have become popular in military and collegiate athletic settings. However, little is known regarding the test-retest reliability or, more importantly, the ability of these systems to accurately identify individuals at risk for MSKI.Purpose:To determine the association between scores from a proprietary MMC movement screen test and the likelihood of suffering a subsequent MSKI and establish the test-retest reliability of the MMC system used.Study Design:Cohort study; Level of evidence, 3.Methods:Trainees for the Air Force Special Warfare program underwent MMC screenings immediately before entering the 8-week training course. MSKI data were extracted from a database for the surveillance period for each trainee. Logistic regression analyses were performed to identify associations between baseline MMC scores and the likelihood of suffering any MSKI or, specifically, a lower extremity MSKI. The test-retest portion of the study collected MMC scores from 10 separate participants performing 4 trials of the standard test procedures. Reliability was assessed using intraclass correlation coefficients by a single rater.Results:Overall, 1570 trainees, of whom 800 (51%) suffered an MSKI, were included in the analysis. MMC scores poorly predicted the likelihood of any or a lower extremity MSKI (odds ratio, 1.01-1.02). Further, receiver operating characteristic curve analyses demonstrated poor sensitivity and specificity for prediction of MSKI with MMC scores (area under the curve = 0.53). Finally, intraclass correlation coefficients from the test-retest analysis of MMC scores ranged from 0.157 to 0.602.Conclusion:This MMC system displayed poor to moderate test-retest reliability and did not demonstrate the ability to discriminate between individuals who were and were not likely to suffer an MSKI.

BackgroundMusculoskeletal injuries (MSKIs) are common in military trainees and present a considerable threat to occupational fitness, deployability, and overall military readiness. Despite the negative effects of MSKIs on military readiness, comprehensive evaluations of the key known and possible risk factors for MSKIs are lacking. The U.S. Army Research Institute of Environmental Medicine (ARIEM) is initiating a large-scale research effort, the ARIEM Reduction in Musculoskeletal Injury (ARMI) Study, to better understand the interrelationships among a wide range of potential MSKI risk factors in U.S. Army trainees in order to identify those risk factors that most contribute to MSKI and may be best targeted for effective mitigation strategies.MethodsThis prospective study aims to enroll approximately 4000 (2000 male and 2000 female) U.S. Army trainees undergoing Basic Combat Training (BCT). Comprehensive in-person assessments will be completed at both the beginning and end of BCT. Participants will be asked to complete surveys of personal background information, medical history, physical activity, sleep behaviors, and personality traits. Physical measurements will be performed to assess anthropometrics, tibial microarchitecture and whole body bone mineral density, muscle cross-sectional area, body composition, and muscle function. Blood sampling will be also be conducted to assess musculoskeletal, genetic, and nutritional biomarkers of risk. In addition, participants will complete weekly surveys during BCT that examine MSKI events, lost training time, and discrete risk factors for injury. Participants’ medical records will be tracked for the 2 years following graduation from training to identify MSKI events and related information. Research hypotheses focus on the development of a multivariate prediction model for MSKI.DiscussionResults from this study are expected to inform current understanding of known and potential risk factors for MSKIs that can be incorporated into solutions that optimize Soldier health and enhance military readiness.

Simple SummaryDespite extensive international research, musculoskeletal injuries remain a key problem for the Thoroughbred racing industry, with multiple welfare and ethical consequences. High-speed exercise (HSE) history is an important risk factor for injury. However, studies report conflicting findings concerning the effect of HSE on the risk of injury. Although most injuries and fatalities occur during training rather than racing, many research studies only evaluate injuries reported on race day, which likely underrepresents the injuries acquired by these horses. This study aimed to determine the effect of combined training and racing HSE on injuries in racehorses. We performed a systematic search of the relevant literature and evaluated the effect of seven measures of HSE on injury through meta-analyses. The total career HSE distance significantly affected the odds of musculoskeletal injuries (MSI). With every 5-furlong (1 km) increase in career HSE distance, the odds of MSI increased by 2%. The average HSE distance per day also affected the odds of MSI. With every additional furlong (200 m) of average HSE per day, the odds of MSI increased by 73%. However, the strength of the available evidence is restricted by methodological limitations, which will need to be addressed in the future, to explore the level of risk and mechanisms for injury in more detail.Despite over three decades of active research, musculoskeletal injuries (MSI) remain a global problem for the Thoroughbred (TB) racing industry. High-speed exercise history (HSEH) has been identified as an important risk factor for MSI. However, the nature of this relationship remains unclear, with an apparent protective effect of HSE against injury, before it becomes potentially harmful. Many MSI cases and fatalities occur during training rather than during racing, resulting in an underestimation of injury from studies focused on race day. The objective of this study was to examine the current evidence of the effect of combined training and racing HSEH on MSI in TB flat racehorses, through a systematic review and meta-analysis. A systematic search of the relevant literature was performed using PubMed®, Scopus®, Web of Science®, and Embase® online databases and the gray literature using sites containing “.edu” or “.edu.au”. Studies included in the review had explored seven different measures of HSE, including total career HSE distance, cumulative HSE distance in the 30 and 60 days before MSI, average HSE distance per day, per event and per 30 days, and the total number of HSE events. The total cumulative career HSE distance significantly affected the odds of MSI, with every 5-furlong increase, the odds of MSI increased by 2% (OR = 1.02; 95% CI 1.01, 1.03; p = 0.004). The average HSE distance per day also affected the odds of MSI, with every additional furlong increasing the odds of MSI by 73% (OR = 1.73; 95% CI 1.29, 2.31; p < 0.001). Other measures of HSE were not found to be consistently associated with risk of MSI, but these results should be interpreted with caution. Significant methodological limitations were identified and influence the comparability of studies. Standardizing the measures of HSE in studies of MSI, and describing training conditions in more detail, would support a more thorough investigation of the relationship between HSE and MSI. An improved understanding of this relationship is critical to mitigating the impact of MSI in the Thoroughbred racehorse.

Vitamin D is an essential nutrient for maintaining bone health. Recent data suggest that vitamin D and calcium supplementation might affect stress fracture incidence in military personnel. Although stress fracture is a health risk for military personnel during training, no study has investigated changes in vitamin D status in Soldiers during United States (US) Army basic combat training (BCT). This longitudinal study aimed to determine the effects of BCT on 25-hydroxyvitamin D (25(OH)D) and parathyroid hormone (PTH) levels in female Soldiers. Serum 25(OH)D and PTH were assessed in 74 fasted Soldier volunteers before and after an 8-week BCT course conducted between August and October in Columbia, South Carolina. In the total study population, 25(OH)D levels decreased (mean ± SD) from 72.9 ± 30.0 to 63.3 ± 19.8 nmol/L (P < 0.05) and PTH levels increased from 36.2 ± 15.8 to 47.5 ± 21.2 pg/mL (P < 0.05) during BCT. Ethnicity affected changes in vitamin D status (ethnicity-by-time interaction, P < 0.05); 25(OH)D decreased (P < 0.05) in both Hispanic and non-Hispanic whites, but did not change in non-Hispanic blacks. Ethnicity did not affect BCT-induced changes in PTH. These data indicate that vitamin D status in female Soldiers may decline during military training in the late summer and early autumn months in the Southeastern US. Future studies should strive to determine the impact of military clothing and seasonality on vitamin D status, as well as the functional impact of declining vitamin D status on bone health.