Risk factors for injuries along an infantry commanders course.

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

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

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

Injury Prevention Exercises for Reduced Incidence of Injuries in Combat Soldiers.

ABSTRACT: Steinberg, N, Bar-Sela, S, Moran, U, Pantanowitz, M, Waddington, G, Adams, R, Band, SS, and Funk, S. Injury prevention exercises for reduced incidence of injuries in combat soldiers. J Strength Cond Res 35(11): 3128-3138, 2021-The aim of this study was to determine the influence of an "all-cause injury" prevention program, focused on static-to-dynamic transitions, on injury prevalence in a military commanders course. Two cohorts of male infantry commanders were recruited (intervention [INT group], n = 196 and controls [CO group], n = 169) and tracked by a physiotherapist, who recorded any injuries that occurred during the 14-week course. Soldiers were tested precourse, midcourse, and postcourse for anthropometrics, proprioception ability, and dynamic postural balance (DPB). The INT group performed injury prevention exercises for 5 minutes, 3 times a week, and the CO group continued with their routine physical fitness sessions. The prevalence of injuries reported to the physiotherapist during the course was significantly lower for the INT group compared with the CO group (14.8 and 34.3%, respectively, p < 0.001). Similarly, rates of injury in the INT group were significantly lower than in the CO group (p < 0.001; hazard = 2.53, 95% confidence interval = 1.62-3.95). Precourse proprioception ability was significantly lower in those that became injured during the commanders course, irrespective of the group. Likewise, for DPB parameters, the injured subjects in both groups had significantly lower precourse scores than the noninjured subjects. From pretesting to midtesting, the injured soldiers in the INT group improved their ability up to the level of the noninjured subjects. A reduced prevalence of injuries was found for soldiers who completed the injury prevention program. Because the subjects soldiers injured on the course had reduced somatosensory abilities at the outset, and as these abilities can be improved by static-to-dynamic exercises, identifying at-risk soldiers and providing them with appropriate strategies for improvement beforehand is indicated.

A balance and proprioception intervention programme to enhance combat performance in military personnel.

BACKGROUND: Optimal functioning of the lower extremities under repeated movements on unstable surfaces is essential for military effectiveness. Intervention training to promote proprioceptive ability should be considered in order to limit the risk for musculoskeletal injuries. The aim of this study was to assess the effect of a proprioceptive intervention programme on static and dynamic postural balance among Israel Defense Forces combat soldiers. METHODS: Twenty-seven male soldiers, aged 18-20 years, from a physical fitness instructor's course, were randomly divided into two groups matched by age and army unit. The intervention group (INT) underwent 4 weeks of proprioceptive exercises for 10 min daily; the control group underwent 4 weeks of upper body stretching exercises for 10 min daily. All participants were tested pre and postintervention for both static and dynamic postural balance. RESULTS: Significant interaction (condition*pre-post-test*group) was found for static postural balance, indicating that for the INT group, in condition 3 (on an unstable surface-BOSU), the post-test result was significantly better compared with the pretest result (p<0.05). Following intervention, the INT group showed significant correlations between static postural stability in condition 2 (eyes closed) and the dynamic postural stability (length of time walked on the beam following fatigue) (r ranged from 0.647 to 0.822; p<0.05). CONCLUSIONS: The proprioceptive intervention programme for combat soldiers improved static postural balance on unstable surfaces, and improved the correlation between static postural balance in the eyes closed condition and dynamic postural balance following fatigue. Further longitudinal studies are needed to verify the relationship between proprioception programmes, additional weight bearing and the reduction of subsequent injuries in combat soldiers.

Examination of the Effectiveness of Predictors for Musculoskeletal Injuries in Female Soldiers.

The amount of training days lost to injury during military training has highlighted the need to identify a screening tool to predict injury. One hundred and fifty-eight female soldiers from the Combat Fitness Instructor Course (CFIC) of the Israel Defense Forces volunteered to participate in this study. All soldiers were free of orthopedic and neurologic conditions for at least one month before the study. All participants performed a battery of measurements during the first week of the course. Measures included anthropometric, functional movement screen (FMS), power performances (counter movement jump [CMJ], drop jump, single leg triple hop jump [SLTH], 10-m sprint) and a 2K run. Injury data was collected throughout the 3 month course. Median tests were used to compare between injured/non-injured soldiers. Chi-square and/or logistic regression analysis was used to examine the association between various predictors and injury. Percent body fat [%BF] was higher (p = 0.04), distance for SLTH was less for both left and right legs (p = 0.029, p = 0.047 respectively) and 2K run was slower (p =0.044) in injured compared to non-injured soldiers. No differences between groups were noted in total FMS score, however more zero scores in one or more movement pattern were found in the injured group (51.35 % vs. 30.5% p=0.0293). Only %BF, 2K run and SLTH distance were significant predictors of injury (p = 0.05, p = 0.02, p =0.016 respectively). The results of this study indicated that the FMS total score is not a predictor of injury in female soldiers in a CFIC. We found that %BF, SLTH, 2K run time, 10 meter sprint time and zero scores differentiated between injured and non-injured soldiers. In addition, %BF, 2K run and SLTH were each found to be separate predictors of injury. Further research is needed to determine threshold scores that predict injury. Key pointsA total of 145 injuries were reported during the three month Combat Fitness Instructor Course in a female soldiers, 37 of these injuries resulted in absence from at least two days of training.FMS total score is not a predictor of injury in female soldiers in a CFIC. However, a score of zero, which is indicative of pain during movement, could serve as a warning sign for potential injury.%BF, SLTH, 10 meter sprint, 2K run and number of zero scores in FMS appear to differentiate between injured and non-injured soldiersSLTH, 2K run and body fat % are each separate predictors of injury for female soldiers in the CFIC.

The Influence of a 14-Week Infantry Commanders Courses on the Achilles Tendon and Patellar Tendon Structure.

INTRODUCTION: Alternated tendon structure may raise stress to the musculoskeletal structures and may increase the potential for overuse injury. Screening the tendon structure of soldiers pre- and post-participation in a strenuous combat course is essential. The aim of the present study was to investigate the influence of a 14-week infantry commanders courses on the Achilles tendon (AT) structure and patellar tendon (PT) structure in combat soldiers. MATERIALS AND METHODS: Ninety-eight participants from an infantry commanders course were screened pre- and post-course for the AT and PT structures, using ultrasonographic tissue characterizaton (UTC) imaging to capture a 3D structure of four echo-type fibers (I-IV). RESULTS: In both tendons, the mean relative frequency of echo-type I fibers significantly decreased from pre- to post-testing, with a significant increase in the relative frequency of echo-types II, III, and IV fibers. In the AT, 60.2% of the subjects showed positive differences (between pre- and post-testing in the echo-type III + IV fiber ("worsened" tendon structure), whereas in the PT, 92.2% of the subject showed an increased frequency. No significant correlation (r = 0.108; P = .324) was found between the differences of echo-type III + IV fibers of the AT and that of the PT. CONCLUSIONS: Loads to the musculoskeletal structures along the combat course increased the mean relative frequency of the "reduced" echo-type fibers (III + IV) in both the AT structure and the PT structure. Yet, whereas in the AT around 40% of the soldiers showed an improved tendon structure along the course, in the PT less than 10% of the soldiers showed that improvement. Soldiers and commanders should be aware of the different influence of the loading exercises along the course on the AT and on the PT structure, as "reduced" tendons structure might put the soldiers at higher risk for injury in the future.

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

OBJECTIVES: The aims of the study were to compare the prevalence of soldiers with musculoskeletal symptoms between soldiers that participated in a prevention program (INT) and a control group (CONT); and, to assess whether 'high risk' for a symptom indicator [participants with patellar tendon (PT) echo-type III+IV >10% or Achilles tendon (AT) echo-type III >8.5%] applies when a prevention intervention is used. METHODS: Soldiers from two consecutive infantry commanders courses (year 1-CONT, n = 165; year 2-INT, n = 196) were examined pre-course for AT and PT structure using ultrasound tissue characterization (UTC), and their musculoskeletal overuse symptoms were assessed and recorded by military physicians throughout the course. A prevention program was provided to the INT group (year 2) during the 14-week course. RESULTS: No significant differences were found in the prevalence of soldiers with symptoms between the two groups [INT: 39 (19.9%), CONT: 40 (24.2%); p = .32]. Using the indicator at baseline, 20 soldiers (10.2%) were suggested to be at 'high risk.' Of those 20 soldiers, 17 actually had symptoms during the course (positive predictive value-85%). The prevalence of soldiers with a suggested 'high risk' according to our indicator who had no symptoms during the course was low (3/20, 15%). Twenty-two soldiers who had symptoms during the course had not been suggested to be at 'high risk' by our indicator. CONCLUSION: Our intervention did not reduce the prevalence of soldiers with symptoms. Our 'high risk' pre-course, AT and PT structure indicator is valid and can be used as a screening tool to reduce the prevalence of symptoms in combat soldiers; with the caution that soldiers that were not identified by the indicator, might also have symptoms along the course.

Factors associated with musculoskeletal injuries in an infantry commanders course.

OBJECTIVES: To evaluate the prevalence of injuries among young combat soldiers as assessed and reported by the military physicians, and to investigate whether parameters such as anthropometric measures, postural balance, proprioceptive ability, and chronic ankle instability are related to injuries during and following an infantry commanders course. METHODS: In this cross-sectional study, 165 soldiers were tested for anthropometric measurements, proprioceptive ability, and dynamic postural balance (DPB), as well as for their responses to an ankle stability questionnaire (CAIT), on three occasions: pre-course, middle-course, and end-course testing. All musculoskeletal injuries were assessed and recorded in the digital medical file of each participant by specialist military physicians before and during/following the course. RESULTS: Ninety-eight soldiers (59.4%) were injured before the course. Forty soldiers (24.2%) incurred an injury during/following the course (with 33 out of the 40 [82.5%] soldiers that were injured during/following the course having also been injured before the course). Sixty soldiers had no injury before/during/following the course. A survival curve showed that half of the soldiers who were injured during/following the course (20 soldiers) were recorded as injured in the first half of the course (during the first 46 days of the 92-day course). Logistic regression showed that the pre-course parameters that were significant among injured soldiers compared with the non-injured soldiers were: low CAIT results (OR = 2.736, 95% CI = 1.178-6.354), high BMI (OR = 1.234, 95% CI = 1.082-1.406) and reduced proprioceptive ability (OR =.858, 95% CI =.797-.924). CONCLUSION: With a high prevalence of soldiers injured during and following a commanders course, a somatosensory intervention program should be generalized into the practical daily preparation and training routines of the soldiers for improving somatosensory abilities, optimizing military physical readiness, and for preventing future musculoskeletal injuries.

Self-reported chronic ankle instability effects on the development of fitness during an Infantry Commanders Course.

OBJECTIVES: To determine whether self-reported chronic ankle instability (CAI) affects the physical performance of soldiers during army training, in routine army fitness tests and other sensorimotor tests. DESIGN: Prospective cohort comparison. METHODS: Soldiers enrolled on the Infantry Commanders Course (ICCourse) of the Israeli Defense Force were tested in weeks one and fourteen of the course, including a 3000 m timed run, an agility test over an X-shaped course, the Y Balance Test (YBT) and the Active Movement Extent Discrimination Assessment (AMEDA) somatosensory test. Soldiers were trained using routine ICCourse physical training throughout the course. Changes in physical performance were analysed using a two-way ANOVA, for soldier groups categorised as having healthy ankles or CAI. RESULTS: Soldiers improved their scores on all 4 tests (3000 m run, X-agility test, YBT and AMEDA) during the course. However, soldiers with CAI did not improve on the X-agility test, whilst those with healthy ankles did. Soldiers with CAI performed worse on the YBT-PM (postero-medial direction) at the start of the course, but this difference was no longer present at 14 weeks. Soldiers with CAI performed better on the AMEDA at the start and 14-week testing points. CONCLUSIONS: Self-reported CAI restricts agility performance gains in soldiers during 14-weeks of physical training but has no effect on 3000 m running performance. Soldiers with CAI perform worse in YBT balance tests. Soldiers with CAI have better proprioceptive acuity than those with stable ankles. These findings indicate possible sensorimotor factors for training of soldiers with known CAI.

The Physiology and Biomechanics of Load Carriage Performance.

Introduction: The weight that soldiers are required to carry in training and in combat has continually increased over the years. Changes in load carried or pace of activity will alter the physiological and biomechanical stress associated with the activity. Whether it is part of the soldier's training or an actual operation, managing the proper load and speed to minimize fatigue can be integral to the soldier's success. Without a proper understanding of the multitude of factors that may affect load carriage performance, mission success may be jeopardized. The purpose of this review is to summarize and clarify the findings of load carriage research and to propose a new method for analyzing the intensity of load carriage tasks, the Load-Speed Index. Materials and Methods: We reviewed studies that examined military load carriage at walking speeds and included articles that featured non-military participants as deemed necessary. Results: Major factors that can affect load carriage performance, such as speed of movement, load carried, load placement, body armor, and environmental extremes all influence the soldier's energy expenditure. A critical aspect of load carriage performance is determining the appropriate combination of speed and load that will maximize efficiency of the activity. At the higher end of walking speeds, the walk-to-run transition represents a potential problem of efficiency, as it may vary on an individual or population basis. Conclusions: This review provides a comprehensive overview of these factors and suggests a new Load-Speed Index, which can be utilized to define thresholds for load and speed combinations and contribute to the understanding of the physiological and biomechanical demands of load carriage marches. The literature recommends that load and speed should be managed in order to maintain an exercise intensity ~45% VO2 max to delay time to fatigue during prolonged marches, and the Load-Speed Index corroborated this finding, identifying 47% VO2 max as a threshold above which intensity increases at a greater rate with increases in load and speed. The Load-Speed Index requires validation as a predictive tool. There are no definitive findings as to how load affects the speed at which the walk-to-run transition occurs, as no investigations have specifically examined this interaction. Additional research is clearly needed by examining a wide range of loads that will facilitate a clearer understanding of speed and load combinations that optimize marching pace and reduce energy expenditure.

Prevalence and Patterns of Injury Sustained During Military Hand-to-Hand Combat Training (Krav-Maga).

BACKGROUND: Krav-Maga (KM) is a unique Israeli hand-to-hand combat system, designed to teach soldiers self-defense in true-to-life situations. With the increase in military Israel Defense Force (IDF) units participating in KM training in recent years, the number of injuries incurred in KM has also increased. The purpose of our report is to describe the prevalence and pattern of these injuries. METHODS: Instances of KM injury were taken from IDF patients' computerized clinical records over a 1-year period. Data pertaining to the type, location, and severity of the injury, as well as data relating to soldier's gender and age were collected from the charts. "Moderate" injury was defined as injury necessitating absence from military activity for more than 1 week; "major" injury was defined as injury necessitating surgical intervention. FINDINGS: During the year 2014, 916 soldiers complaining of 946 traumatic injuries sustained during KM training were evaluated in IDF clinics. The vast majority of injuries (95%) occurred in male soldiers, and most injured soldiers (92%) were between the ages of 18 and 22. The upper limbs were the most frequently injured body parts, with the fingers, hands, and wrists being the most involved regions (31%) followed by the shoulder (16%). Injury severity was mild in most cases. However, 64 soldiers (6.7%) were moderately injured and major injuries necessitating surgical treatment occurred in 33 cases (3.5%). DISCUSSION: KM involves both striking and grappling elements, and we assume that injuries result from both fighting forms. With striking styles, such as boxing and kickboxing, hand and wrist are the prevalent injury locations; with grappling styles such as wrestling, strain and sprain injuries of large joints are most prevalent. Head and neck injuries, a major concern in martial arts sports, were not identified as significant problems in KM. To minimize participant injury, preventative measures should focus on improving protective equipment, especially of the hand, as well as warm up and training technique modifications, and shoulder strengthening exercises.

The effect of HMB ingestion on the IGF-I and IGF binding protein response to high intensity military training.

OBJECTIVE: Insulin-like growth factor-I (IGF-I) is a metabolic and anabolic biomarker that has been proposed to reflect physiological adaptations resulting from multistressor environments. The bioactivity of IGF-I is regulated by seven different insulin-like growth factor binding proteins (IGFBPs) which act not only as carriers of IGF-1, but also function as a modulator of IGF-I availability and activity. Supplementing with ß-hydroxy-ß-methylbutyrate (HMB) has been shown to enhance physiological outcomes associated with intense training, and has been reported to augment the IGF-1 response. The purpose of this study was to examine the effect of 23days of HMB supplementation on circulating levels of IGF-I and IGFBPs in combat soldiers during highly intense military training. METHODS: Thirteen male soldiers from an elite infantry unit volunteered to participate in this double-blind, parallel design study. Soldiers were provided 3g·day-1 of either HMB (n=6) or placebo (PL; n=7). During the study soldiers performed advanced military training with periods of restricted sleep and severe environmental stressors. Blood samples were obtained prior to (PRE) and approximately 18h following the final supplement consumption (POST). RESULTS: No significant differences were observed for circulating IGF-1 concentrations between HMB and PL (p=0.568). In addition, no differences were seen between the groups for IGFBP-1 (p=1.000), IGFBP-2 (p=0.855), IGFBP-3 (p=0.520), IGFBP-4 (p=0.103), IGFBP-5 (p=0.886), or IGFBP-6 (p=0.775). A significant difference was noted between HMB (169.9±23.0ng·ml-1) and PL (207.2±28.0ng·ml-1) for IGFBP-7 at POST (p=0.042). CONCLUSIONS: Although the results of this study do not support the influence of HMB supplementation on circulating concentrations of IGF-1 or IGFBPs1-6 during high intensity military training, it does present initial evidence that it may lower circulating IGFBP-7 concentrations. This may provide some indication of a reduced stress response, but further investigation on the physiological role of IGFBP-7 and military training is needed.

ß-Hydroxy-ß-methylbutyrate attenuates cytokine response during sustained military training.

This study tested the hypothesis that of 23 days of ß-hydroxy-ß-methylbutyrate (HMB) supplementation can maintain muscle mass and attenuate the immune and inflammatory response in combat soldiers during highly intense military training. Soldiers were randomly assigned to either a HMB (n = 6) or placebo (PL; n = 7) group and provided with 3 g · day(-1) of either HMB or PL. During the final week of supplementation soldiers participated in extreme physical training, which included night navigation of 6-8 hours across difficult terrain carrying heavy loads combined with sleep deprivation (3.8 ± 3.0 h per night). Blood draws were performed prior to and following the supplementation period. Magnetic resonance imaging, which included diffusion tensor imaging sequence, was used for muscle fiber tracking analysis. Data was analyzed using a two-way mixed factorial analysis of variance. Magnitude-based inferences were used to provide inferences on the true effects that HMB may have had on the dependent variables compared to PL, calculated from 90% confidence intervals. Changes in tumor necrosis factor-α for HMB (-3.9 ± 8.2 pg · mL(-1)) were significantly lower (P = .043) compared to the change in PL (+4.0 ± 3.7 pg · mL(-1)). HMB ingestion was also very likely (92%-95% Likelihood) to lower granulocyte colony-stimulating factor and interleukin 10 compared to PL. In addition, HMB supplementation was likely (78%-87% likelihood) to reduce interferon-γ, interleukin 8, CX3CL1, and increase muscle volume for the adductor magnus (77% likelihood) compared to PL. In summary, the results of this study provides evidence that HMB supplementation may attenuate the inflammatory response to high intense military training, and maintain muscle quality.

Femoroacetabular impingement syndrome is associated with alterations in hindfoot mechanics: A three-dimensional gait analysis study.

BACKGROUND: Gait analysis studies in patients with femoroacetabular impingement syndrome focused until today on alterations in pelvic and hip mechanics, but distal articulations in this syndrome were not explored. Viewing the inter-relationships between foot and hip mechanics and the importance of the subtalar joint in load attenuation at heel strike and during forward propulsion thereafter, alterations in hindfoot mechanics in this syndrome may have clinical significance. METHODS: Three-dimensional gait kinematics were explored with emphasis on hindfoot mechanics in a group of 15 men with cam-type femoroacetabular impingement and compared to 15 healthy men. FINDINGS: Subjects with femoroacetabular impingement had decreased pelvic internal rotation (effect size=0.70) and hip abduction (effect size=0.86) at heel strike, and increased sagittal pelvic range of motion during the stance (effect size=0.81), compared to controls. At the hindfoot level, subjects with femoroacetabular impingement had inverted position at heel strike compared to neutral position in controls (effect size=0.89), and reduced maximum hindfoot eversion during the stance (effect size=0.72). Range of motion from heel strike to maximum eversion was not different between the groups (effect size=0.21). INTERPRETATION: Young adult men with cam-type femoroacetabular impingement syndrome present excessively inverted hindfoot at the moment of heel strike and reduction in maximum eversion during the stance phase. Viewing the deleterious effects of hindfoot malalignment on load attenuation during the stance, custom-designed insoles may be a consideration in this population and this should be investigated further.