Daily Naltrexone Use Does Not Adversely Affect Physical, Cognitive or Marksmanship Performance in U.S. Army Soldiers.

INTRODUCTION: Considering the potential of weaponized opioids, evaluating how prophylactic countermeasures affect military-relevant performance is necessary. Naltrexone is a commercially available Food and Drug Administration-approved medication that blocks the effects of opioids with minimal side effects. However, the effects of naltrexone on the health and performance of non-substance abusing military personnel are not well described in the existing literature. METHODS: Active duty U.S. Army Soldiers (n = 16, mean ± SD, age: 23.1 ± 5.3 y) completed a series of physical, cognitive, and marksmanship tasks during a 4-day pretrial, a 7-day active trial, and a 4-day post-trial phase. During the active trial, participants were administered 50 mg of oral naltrexone daily. Physiological and biological processes were monitored with a daily review of systems, sleep monitoring, biochemistry, and hematology blood panels. RESULTS: Naltrexone did not negatively affect physical performance, cognitive functioning, marksmanship, or sleep duration (P > 0.05). Improvements were observed during the active trial compared to the pretrial phase in cognitive tasks measuring logical relations (P = 0.05), matching to sample (P = 0.04), math speed (P < 0.01), math percent correct (P = 0.04), and spatial processing (P < 0.01). Results from biochemistry and hematology blood panels remained within clinically normative ranges throughout all phases of the study. No participants were medically withdrawn; however, one participant voluntarily withdrew due to nausea and reduced appetite. CONCLUSIONS: Temporary (7-day) daily use of naltrexone was safe and did not negatively affect physical performance, cognitive functioning, marksmanship ability, or sleep in a healthy cohort of U.S. Army Soldiers.

Predicting Postoperative Injury and Military Discharge Status After Knee Surgery in the US Army.

BACKGROUND: Researchers have assessed postoperative injury or disability predictors in the military setting but typically focused on 1 type of surgical procedure at a time, used relatively small sample sizes, or investigated mixed cohorts with civilian populations. PURPOSE: To identify the relationship between baseline variables and injury incidence or military discharge status in US Army soldiers after knee surgery. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: Data were obtained from a repository containing personnel, performance, and medical records for all active-duty US Army soldiers. Multivariate logistic regressions were used to estimate the effects of numerous variables on postoperative injury or on medical discharge. Variable selection and model validation were conducted using the k-fold method. RESULTS: A total of 7567 soldiers underwent knee surgery between 2017 and 2019. Meniscal procedures were the most common type of surgery (39%), and approximately 71% of the cohort had a postoperative injury. Significant predictors for sustaining a postoperative injury included having a previous nonknee injury (odds ratio [OR], 1.5), female sex (OR, 1.3), and Black race (OR, 1.2). Within 4 years after surgery, 17% of soldiers were discharged from the military because of knee-related disability. Significant predictors for discharge from duty included enlisted rank (OR, 2.3), recent fitness test failure (OR, 1.9), number of previous knee surgeries (OR, 1.7), and having a previous nonknee injury (OR, 1.6). CONCLUSION: After knee surgery, nearly three-fourths of the soldiers in this cohort sustained a postoperative injury and almost one-fifth of soldiers were medically discharged from the military within 4 years. This study identified variables that indicate statistically increased risk for these postoperative outcomes and highlighted potentially modifiable factors.

A Narrative Review of Performance and Health Research in US Army Rangers.

ABSTRACT: Roberts, BM, Mantua, J, Naylor, JA, and Ritland, BM. A narrative review of performance and health research in US army rangers. J Strength Cond Res 37(5): 1157-1161, 2023-The 75th Ranger Regiment (75RR) is an elite airborne infantry unit that is prepared to deploy on short notice and is resourced to maintain exceptional proficiency and readiness through prolonged deployments. Soldiers must be airborne qualified and pass a number of physical and psychological tests during training to become a member of 75RR. Rangers must maintain a level of physical performance comparable to high-level athletes while also handling operational stressors that include a negative-energy balance, high-energy expenditure, sleep restriction, and completing missions in extreme environments, all of which increase their chance of illness or infection. There are also situations of heighted injury risk, such as parachuting and repelling, which are routinely required in combat operations. Thus far, only one screening tool to assess injury risk has been developed. There are also physical training programs to enhance performance for Rangers in 75RR. This narrative review aims to evaluate the body of literature surrounding performance and health-related research in US Army Rangers to understand how Rangers are impacted during training or operations, to inform future training recommendations, and to identify areas of future research that are warranted and could potentially optimize the health and performance of Rangers during future training or operation events.

The relationship between sleep, pain,and musculoskeletal injuries in US Army Soldiers.

INTRODUCTION: The purpose of this study was to investigate the relationship between sleep and pain in military personnel and to determine if metrics of sleep and pain intensity differ between the injured and uninjured in this population. METHODS: Active-duty US Army Soldiers (n=308; 26.8±6.5 years, 82% male) from the 2nd Infantry Division, Joint Base Lewis-McChord, Washington, and 101st Airborne Division, Fort Campbell, Kentucky, completed the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), and questionnaires about current musculoskeletal injuries and pain intensity (0=no pain to 10=worst imaginable pain). Pearson correlation coefficients were used to assess the association between pain and sleep. Differences in sleep and pain between injured and uninjured participants were determined using an analysis of covariance. RESULTS: Pain intensity was positively correlated with sleep quality (global PSQI score, r=0.337, p<0.001) and daytime sleepiness (ESS score, r=0.163, p=0.005), and negatively associated with sleep duration (r=-0.118, p=0.039). Injured participants accounted for 37.7% (n=116) of the study population. Injured participants reported greater pain intensity (3.7±2.5 vs 1.3±1.9, p<0.001), were older (28.5±7.4 years vs 25.8±5.7 years, p=0.001) and in the service longer (6.3±6.3 years vs 4.6±4.7 years, p=0.013) than uninjured participants. Injured participants had higher global PSQI scores (9.0±4.1 vs 6.4±3.4, p<0.001), including each of the seven PSQI components (all p<0.050), and reported sleeping less per night than uninjured participants (5.7±1.3 hours vs 6.1±1.2 hours, p=0.026). CONCLUSION: These data demonstrate that pain intensity is associated with sleep in active-duty US Army Soldiers and that those who report a musculoskeletal injury, regardless of age and time in service, report poorer sleep quality, shorter sleep durations, and greater levels of pain than uninjured Soldiers.

Short-term neurochemical effects of transcutaneous trigeminal nerve stimulation using 7T magnetic resonance spectroscopy.

BACKGROUND AND PURPOSE: The purpose was to explore the effects of transcutaneous trigeminal nerve stimulation (TNS) on neurochemical concentrations (brainstem, anterior cingulate cortex [ACC], dorsolateral prefrontal cortex [DLPFC], ventromedial prefrontal cortex [VMPFC], and the posterior cingulate cortex [PCC]) using ultrahigh-field magnetic resonance spectroscopy. METHODS: This double-blinded study tested 32 healthy males (age: 25.4 ± 7.3 years) on two separate occasions where participants received either a 20-minute TNS or sham session. Participants were scanned at baseline and twice post-TNS/sham administration. RESULTS: There were no group differences in concentration changes of glutamate, gamma-aminobutyric acid, glutamine, myoinositol (mI), total N-acetylaspartate, total creatine (tCr), and total choline between the baseline scan and the first post-TNS/sham scan and between the first and second post-TNS/sham scan in the brainstem, ACC, DLPFC, VMPFC, and PCC. Between the baseline scan and the second post-TNS/sham scan, changes in tCr (mean difference = 0.280 mM [0.075 to 0.485], p = .026) and mI (mean difference = 0.662 mM [0.203 to 1.122], p = .026) in the DLPFC differed between groups. Post hoc analyses indicated that there was a decrease in tCr (mean change = -0.201 mM [-0.335 to -0.067], p = .003) and no change in mI (mean change = -0.327 mM [-0.737 to 0.083], p = .118) in the TNS group; conversely, there was no change in tCr (mean change = -0.100 mM [-0.074 to 0.274], p = .259) and an increase in mI (mean change = 0.347 mM [0.106 to 0.588], p = .005) in the sham group. CONCLUSION: These data demonstrate that a single session of unilateral TNS slightly decreased tCr concentrations in the DLPFC region.

Sleep and Injuries in Military Personnel With Suggestions for Improving Sleep and Mitigating Effects of Sleep Loss.

Sleep professionals suggest adults should sleep at least seven hours per night and define good sleep quality as 1) sleep onset =15 minutes, 2) one or fewer awakenings per night, 3) awake after sleep onset =20 minutes, and 4) sleep efficiency (ratio of sleep time to time in bed) =85%. This paper focuses on associations between injuries and sleep quality/duration among military personnel and strategies to optimize sleep and mitigate effects of sleep loss. Investigations among military personnel generally used convenience samples who self-reported their injury and sleep quality/quantity. Despite these limitations, data suggest that lower sleep quality or duration is associated with higher risk of musculoskeletal injury (MSI). Possible mechanisms whereby poor sleep quality/duration may influence MSI include hormonal changes increasing muscle catabolism, increases in inflammatory processes affecting post-exercise muscle damage, and effects on new bone formation. Sleep can be optimized by a slightly cool sleeping environment, bedding that maintains a stable thermal microclimate around the body, not using media devices near bedtime or in the sleeping environment, minimizing noise, and having regular bed and awaking times. Sleep loss mitigation strategies include napping (<30 to 90 minutes), sleep banking (extended time in bed), and judicious use of caffeine or modafinil.

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

INTRODUCTION: Musculoskeletal injuries (MSKIs) are a significant health problem in the military. Accordingly, identifying risk factors associated with MSKI to develop targeted strategies that attenuate injury risk remains a top priority within the military. Insufficient sleep has garnered increased attention as a potential risk factor for MSKI in both civilians and military personnel. Yet, there are no systematic evaluations of the potential association between sleep and MSKI in the military. The purpose of this review is to examine the relationship between sleep and injury in military personnel. MATERIALS AND METHODS: Literature searches were performed in multiple electronic databases using keywords relevant to sleep quantity and quality, MSKI, and military populations. Two investigators independently assessed the methodological quality of each study using the Newcastle-Ottawa Scale for cohort studies or an adapted form of this scale for cross-sectional studies. RESULTS: The search yielded 2402 total citations, with 8 studies (3 cohort and 5 cross-sectional) fitting the inclusion criteria. Overall, the systematic review found 5 of the 8 reviewed studies supporting an association between sleep (quality and duration) and MSKI in military personnel. Specifically, poor sleep was associated with increased injury incidence in 2 cohort and 3 cross-sectional studies. CONCLUSION: This is the first systematic review to evaluate the published literature on the association between sleep and MSKI risk in military populations. Although there is currently limited research on this topic, findings suggest that sleep is associated with MSKI and should be considered when designing strategies aimed at reducing MSKI risk in military personnel.

The Occupational Military Neuromusculoskeletal Injury Matrix.

INTRODUCTION: Neuromusculoskeletal injuries (NMSKIs) are the primary cause of ambulatory visits, lost duty days, and disability discharges in the U.S. Military. Methods for accurately grouping injury diagnoses are required to allow for surveillance and research identifying risk factors and prevention strategies. The CDC method of grouping these diagnoses includes only the S and T codes (Injury, poisoning, and certain other consequences of external causes) from the ICD-10-CM. However, this does not include the majority of the NMSKI depleting soldier readiness; the M (Disease of the musculoskeletal system and connective tissue) and G (Diseases of the nervous system) codes should be included as these also contain injuries. The goal was to develop a new matrix that would comprehensively capture all NMSKIs experienced by military personnel. This paper details the development of the Occupational Military Neuromusculoskeletal Injury (OMNI) Matrix and characterizes the number and rates of active duty U.S. Army injuries as measured by the OMNI compared to other matrices. MATERIALS AND METHODS: A team of researchers including physical therapists, physician assistants, occupational therapists, physicians, and epidemiologists developed the OMNI. The OMNI utilizes the commonly accepted injury definition inclusive of any anatomical complaint resulting in pain or dysfunction and categorizes injuries from the G, M, S, and T codes. The OMNI follows the CDC's matrix structure with three body region levels, each becoming more specific, and adds two levels called Description of the Injury. Additionally, the OMNI categorizes injuries as Injury Type (Acute, Overuse, Either, or Not Applicable), NMSKI-Type (NMSKI, NMSKI that could be caused by occupational/training tasks, and not an NMSKI), and a miscellaneous category that demarks injuries as Superficial, Blood Vessels, and/or Internal Organs. The different grouping methods in the OMNI provide standardization for many possible injury case definitions. The OMNI allows these injury categories to be included/excluded in a standardized fashion to meet the researchers' scientific questions. To enumerate the number of NMSKI that would be captured by the available matrices, the OMNI, the CDC's matrix, and the U.S. Army Public Health Center's (APHC) Taxonomy of Injuries were applied to active duty Army outpatient population data and all incident NMSKI diagnostic codes entered in electronic medical provider encounters for calendar years 2017 and 2018. RESULTS: Using the OMNI resulted in the capture of over 800,000 more injuries than the CDC's matrix and over 200,000 more than the APHC Taxonomy. The NMSKI rate utilizing the OMNI was 193 per 100 soldier-years in 2017 (892,780 NMSKI) compared to 23 per 100 soldier-years for the CDC's matrix, and 141 per 100 soldier-years for the APHC Taxonomy. CONCLUSION: The OMNI provides an updated standardized method of assessing injuries, particularly in occupational military injury research, that can be utilized for Military Performance Division of injury across many countries and still allow for replication of methods and comparison of results. Additionally, the OMNI has the capacity to capture a greater burden of injury beyond what is captured by other available matrices.

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

INTRODUCTION: Musculoskeletal injuries and insufficient sleep are common among U.S. Army Rangers. There has been limited research into whether indices of sleep differ between injured and uninjured Rangers. The purpose of this study was to investigate the association between self-reported sleep and musculoskeletal injury in Rangers. MATERIALS AND METHODS: A total of 82 Army Rangers (male, 25.4 ± 4.0 years) were asked if they currently have any musculoskeletal injuries; completed the Pittsburgh Sleep Quality Index (PSQI), the Insomnia Severity Index (ISI), and the Stanford Sleepiness Scale; and were asked about their average sleep quality/sleep duration over the preceding week. Rangers were then dichotomized into groups, one that reported a current musculoskeletal injury and another that did not. RESULTS: The reported musculoskeletal injury prevalence was 15.9% (n = 13). The Rangers that reported an injury, compared to those that did not, had a significantly higher Global PSQI score (6.7 ± 3.7 versus 4.5 ± 2.7, P = .012) and ISI score (10.9 ± 3.7 versus 7.2 ± 4.1, P = .003), both indicative of poorer sleep. The group reporting an injury rated their average sleep quality over the preceding week significantly lower compared to those that did not report an injury (50.8 ± 17.5 versus 68.9 ± 18.3, P = .001). There was no significant group difference in the average nightly sleep duration (6.1 ± 1.0 hours versus 6.5 ± 0.9 hours, P = .099). CONCLUSION: In this cohort of male Army Rangers, In this cohort of male Army Rangers, those with a musculoskeletal injury reported poorer sleep quality than uninjured Rangers. Sleep duration was not associated with reported injuries; however, both the injured group and uninjured group averaged less than the recommended amounts of sleep. Further investigation into the relationship between musculoskeletal injury and sleep in military personnel is warranted.

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

OBJECTIVES: Explore the impact transitioning from daytime to nighttime operations has on performance in U.S. Army Rangers. METHODS: Fifty-four male Rangers (age 26.1±4.0 years) completed the Y-Balance Test (YBT), a vertical jump assessment, and a grip strength test at three time points. Baseline testing occurred while the Rangers were on daytime operations; post-test occurred after the first night into the nighttime operation training (after full night of sleep loss), and follow-up testing occurred six days later (end of nighttime training). RESULTS: On the YBT, performance was significantly worse at post-test compared to baseline during right posteromedial reach (104.1±7.2cm vs 106.5±6.7cm, p=.014), left posteromedial reach (105.4±7.5cm vs 108.5±6.6cm, p=.003), right composite score (274.8±19.3cm vs 279.7±18.1cm, p=.043), left composite score (277.9±18.1cm vs 283.3±16.7cm, p=.016), and leg asymmetry was significantly worse in the posterolateral direction (4.8±4.0cm vs 3.7±3.1cm, p=.030) and the anterior direction (5.0±4.0cm vs 3.6±2.6cm, p=.040). The average vertical jump height was significantly lower at post-test compared to baseline (20.6±3.4 in vs 21.8±3.0 in, p=.004). Baseline performance on YBT and vertical jump did not differ from follow-up. CONCLUSIONS: Army Rangers experienced an immediate, but temporary, drop in dynamic balance and vertical jump performance when transitioning from daytime to nighttime operations. When feasible, Rangers should consider adjusting their sleep cycles prior to anticipating nighttime operations in order to maintain their performance levels. Investigating strategies that may limit impairments during this transition is warranted.

Sleep and occupational well-being in active duty special operations soldiers: A replication and expansion.

OBJECTIVE: To assess the relationship between sleep quality and occupational well-being in active duty military Service Members. DESIGN: Longitudinal prospective analysis. SETTING: An annual military training event. PARTICIPANTS: US Army special operations Soldiers (n = 60; 100% male; age 25.41 ± 3.74). INTERVENTION: None. MEASUREMENTS: The Pittsburgh Sleep Quality Index (PSQI) was administered prior to the training event, and the Emotional Exhaustion Scale, the Role Overload Scale, the Walter Reed Army Institute of Research Soldier-Specific Functional Impairment Scale, and the Perceived Stress Scale were administered after the event. Linear regression models were used to assess the relationship between sleep and occupational wellness measures, and the outcome measures of "good" and "poor" sleepers (per the PSQI scoring criteria) were compared with Student's t tests. RESULTS: Higher (poorer) PSQI Global Scores predicted poorer occupational wellness of all measures (emotional exhaustion: B = 1.60, P < .001, R2 = 0.25; functional impairment: B = 0.29, P = .03, R2 = 0.14; role overload: B = 0.28, P = .008, R2 = 0.12; and perceived stress: B = 0.34, P = .004, R2 = 0.20). There were additional relationships between specific PSQI component scores and occupational wellness measures, which is a replication of This team's previous work. Furthermore, emotional exhaustion (t(58) = -4.18, P < .001), functional impairment (t(59)= -3.68, P = .001), role overload (t(58) = -3.20, P = .002), and perceived stress (t(58) = -2.43, P = .02) were all higher in poor sleepers. CONCLUSIONS: The findings of this study suggest that US Army special operations Soldiers who have poorer sleep quality may be at increased risk for having poorer occupational well-being.

Effect of Self-Controlled Practice on Neuro-Cortical Dynamics During the Processing of Visual Performance Feedback.

Evidence has accumulated that learners participating in self-controlled practice can both acquire skills and process task-relevant information more effectively than those participating in externally controlled practice. However, the impact of self-controlled practice on neuro-cognitive information processing during visual performance-related feedback has received limited investigation. We expected that individuals participating in self-controlled practice would exhibit elevated neuro-cognitive information processing, as assessed via electroencephalography (EEG), compared with those engaged with externally controlled practice. Participants practiced a golf-putting task under self-controlled or externally controlled (yoked) conditions while EEG data were recorded. Results indicated that EEG theta power was maintained at an elevated level during the feedback period in the self-controlled group relative to the yoked group. The yoked group did not display increases in theta power until the time at which the ball stopped. Both groups displayed similar improvement over the course of the experiment. Correlational analyses revealed that performance improvement within each group was related differently to EEG theta power. Specifically, the self-controlled group displayed positive relationships between theta power and performance improvement, while the yoked group displayed negative relationships. These results have implications regarding the relative effectiveness of self-controlled and externally controlled practice and the instances in which they may provide the most benefit.

Sleep health of incoming army trainees and how it changes during basic combat training.

OBJECTIVE: To examine the sleep health of incoming Army trainees and how it is impacted during basic combat training (BCT). DESIGN: Prospective. SETTING: BCT site (Fort Jackson, SC). PARTICIPANTS: A total of 1349 trainees (936 = male, 413 = female, 20.73 ± 3.67 years). MEASUREMENTS: Participants completed the Pittsburgh Sleep Quality Index (PSQI), the Morningness/Eveningness Questionnaire, and the Epworth Sleepiness Scale at the start of BCT and a modified PSQI at the end of BCT. RESULTS: At baseline, trainees reported an average sleep duration of 7.65 ± 1.68 hours per night, with 81.8% rating their sleep quality as "Very Good or Fairly Good." The mean reported Morningness/Eveningness Questionnaire score was 50.63 ± 8.11 and the mean Epworth Sleepiness Scale was 8.60 ± 4.02. Reported sleep duration was significantly less during BCT (6.73 ± 0.90 hours) compared to baseline (P< .001). There was no significant difference in the mean PSQI Global score at the end of BCT compared to the start (5.33 ± 3.00 vs. 5.42 ± 2.85, P = .440), however, 6 of the 7 component scores were significantly different (with Sleep Quality, Sleep Duration, and Daytime Dysfunction scores being higher/worse and Sleep Latency, Sleep Efficiency, and Sleep Medication Use scores being lower/improved [all P < .01]). CONCLUSIONS: Army BCT trainees in this large sample reported good sleep health characteristics at entry to training, including achieving recommended sleep amounts (>7 hours per night) and reporting good sleep quality. During BCT, negative changes were observed in reported sleep duration and quality in trainees. Further investigation into the factors contributing to changes in trainees' sleep health during BCT and the implications on subsequent readiness, injury risk, and performance is warranted.

Geographically based risk assessment of sleep disorders and disease states impacting medical readiness across active duty army installations from military medical databases in fiscal year 2017.

BACKGROUND: The impact of sleep disorders on active duty Soldiers' medical readiness is clinically significant. Sleep disorders often present high comorbidity with disease states impacting readiness ranging from obesity and drug dependence. Patient data generated from military health databases can be accessed to examine such relationships. The current study performed a risk assessment of sleep disorders, obesity, tobacco use, and substance abuse based on geographical distribution of active duty Army installations through a comprehensive analysis of the Office of the Army Surgeon General Health of the Force report, specifically for Fiscal Year 2017, which summarizes data collected during 2016. METHODS: Health incidences (percent active duty per installation) were queried from the Health of the Force Fiscal Year 2017 (n = 471,000; 85.5% male, >70% between 18 and 34). Nonparametric ranked tests identified active duty Army installations at low risk (green; <25% percentile relative to mean rank), moderate risk (amber; 25%-50% percentile relative to mean rank), and high risk (red; >75% percentile relative to mean rank). Pearson's correlations determined extent of generalized comorbidity of sleep disorders with obesity, tobacco use, and substance abuse across all installations. RESULTS: Large combat arms and training installations of the Southern U.S. were at highest risk for sleep disorder. Mean rank comparisons for sleep disorders versus obesity (P = .306), tobacco use (P = .378), and substance abuse (P = .591) did not differ for each installation. There was a high degree of generalized comorbidity of diagnosed sleep disorder with obesity (P < .001; r2 = 0.963), tobacco use (P < .001; r2 = 0.928), and substance abuse (P < .001; r2 = 0.968). CONCLUSIONS: These risk assessments mirror geographical risk data from civilian populations which is surprising because there is a large degree of inter-individual variability in geographical origin, race/ethnicity, and socioeconomic statuses within a single Army installation. Nevertheless, these data demonstrate strong geographical influences on medical readiness in active duty Soldiers comparable to civilian sectors.

Sleep loss is related to unstable stationary balance in U.S. Army soldiers in an operationally-relevant context.

BACKGROUND: Sleep loss negatively impacts stationary balance in a laboratory setting, but few studies have examined this link in a naturalistic environment. We tested this relationship in U.S. Army soldiers that often undergo mission-driven sleep loss and who conduct high-risk operations on precarious terrain. METHODS: Stationary balance was tested before and after a mission night. RESULTS: After mission-driven sleep loss, in more difficult conditions (but not easy conditions) balance was more unstable and more variable than a rested baseline condition. Furthermore, habitual sleep quality prior to sleep loss predicted the balance decrement after sleep loss. CONCLUSIONS: Therefore, mission-driven sleep loss may negatively impact soldier balance, but better sleep prior to the mission may mitigate these negative effects.

Sleep health and its association with performance and motivation in tactical athletes enrolled in the Reserve Officers' Training Corps.

OBJECTIVE: To examine habitual sleep health and investigate how habitual sleep duration impacts performance and motivation in Reserve Officers' Training Corps (ROTC) tactical athletes. DESIGN: Observational. SETTING: A large, state university. PARTICIPANTS: Fifty-four young tactical athletes enrolled in ROTC. MEASUREMENTS: Participants wore wrist actigraph devices and completed sleep diaries for 7 days prior to completing a cognitive/motor test battery. RESULTS: The mean objective total sleep time of the participants was 6.17 ±â€¯0.69 hours, with only 7.4% of participants averaging ≥7 hours of sleep per day. A mean sleep quality rating between "Poor" and "Fair" was reported by 22.2% of participants. The mean Epworth Sleepiness Scale rating was 8.80 ±â€¯3.24, with 27.8% of participants reporting scores >10. Controlling for age and gender, the average objective total sleep duration was significantly associated with performance on the Symbol Digit Modalities Test (P = .026) and with motivation levels to perform the cognitive/motor battery (P = .016), but not with performance on the Psychomotor Vigilance Test, Flanker task, Trail Making Test, or Standing Broad Jump. CONCLUSIONS: ROTC tactical athletes habitually sleep less than the recommended 7 hours per day with roughly one-fourth reporting excessive daytime sleepiness and one-fifth reporting poor sleep quality, which may increase their risk for future adverse health outcomes. Longer sleep durations were associated with higher motivation levels and better cognitive processing speed performance; however, they were not associated with executive function, psychomotor vigilance, or broad jump performance.

Effects of sleep extension on cognitive/motor performance and motivation in military tactical athletes.

OBJECTIVE: Investigate the immediate and residual impacts of sleep extension in tactical athletes. METHODS: A randomized controlled trial (Sleep extension = EXT vs Control = CON) was conducted on 50 (EXT: 20.12 ± 2.01 years vs CON: 19.76 ± 1.09 years) tactical athletes enrolled in the Reserve Officers' Training Corps (ROTC). Participants wore actigraphs for 15 consecutive nights and completed a cognitive/motor battery after seven habitual sleep nights, after four sleep extension nights, and after the resumption of habitual sleep for four nights. The CON group remained on habitual sleep schedules for the entire study. RESULTS: During the intervention, the EXT group significantly increased mean sleep time (1.36 ± 0.71 h, p < 0.001). After sleep extension, there were significant between-group differences on the mean score change since baseline in Psychomotor Vigilance Test (PVT) reaction time (p = 0.026), Trail Making Test (TMT) - B time (p = 0.027), standing broad jump (SBJ) distance (p < 0.001), and motivation levels [to perform the cognitive tasks (p = 0.003) and the SBJ (p = 0.009)]; with the EXT group showing a greater enhancement in performance/motivation. After resuming habitual sleep schedules, significant between-group differences on the mean score change since baseline persisted on SBJ distance (p = 0.001) and motivation to perform the SBJ (p = 0.035), with the EXT showing greater enhancement in performance/motivation. CONCLUSION: Increasing sleep duration in military tactical athletes resulted in immediate performance benefits in psychomotor vigilance, executive functioning, standing broad jump distance, and motivation levels. Benefits on motor performance were evident four days after resumption of habitual sleep schedules. Military tactical athletes aiming to optimize their overall performance should consider the impact of longer sleep durations when feasible.

A description of injuries in men and women while serving in Afghanistan.

Musculoskeletal injuries (MSIs) are the most common cause of ambulatory visits in the deployed setting. Research done on deployed populations have focused mostly on men. The purpose of this retrospective cohort study was to describe physical demands and MSIs among male and female soldiers in a Brigade Combat Team during a 12-month deployment to Afghanistan. Data on occupational tasks and injuries were collected from the infantry and brigade support battalions. Out of 57 women, 22 had MSIs (39%) and for the 536 men, 120 (22%) had MSIs resulting in limited duty. The average limited duty was 7.5 and 13 days/injury for women and men, respectively. The most commonly injured body region for the men was the low back (32%) and the low back (22%) and foot and ankle (22%) for women. The activity associated with MSI for women was physical training (25%) and for men it was contact with the enemy (23%). Physically demanding duties, more distance walked, and heavier average load and objects lifted all increased the risk of injury in women. Only lifting heavier weights increased the risk in men. The women appear to have less tolerance to physically demanding work such than their male counterparts.

Risk factors for musculoskeletal injuries for soldiers deployed to Afghanistan.

PURPOSE: This study determined injury incidence and examined the association between musculoskeletal injuries and potential intrinsic and extrinsic risk factors. METHODS: This retrospective cohort study involved a survey of 593 volunteers from two battalions of a Stryker Brigade Combat Team upon completion of a 12-mo deployment to Afghanistan. The survey included questions on physical characteristics, work duties, equipment worn, fitness training, and injuries experienced during the deployment. RESULTS: Of the surveyed soldiers, 45% sustained an injury during the deployment. Total injuries resulted in 5049 d of limited duty, an average of 8.5 d per injury. The body regions with the largest numbers of injuries were the low back (17.4%), knee (12.7%), and shoulder (10.0%). The majority (65%) of injuries occurred while working. The most frequent activities soldiers reported as the cause of injury were lifting and carrying (9.8%), dismounted patrolling (9.6%), and physical training (8.0%). Older age, higher enlisted rank, female sex, months deployed, more time spent standing, longer strength training sessions, heaviest load worn, and heavier or more frequent lifting tasks were all associated with injury. DISCUSSION: Tasks requiring physical energy expenditure such as load carriage, lifting, or standing resulted in an increased risk of musculoskeletal injury in this study. Lifting/carrying, dismounted patrols, and physical training were associated with 26% of musculoskeletal injuries. The weight of loads carried and lifting may be exceeding the work capacity of the soldiers, resulting in injury. These injuries in turn limit available work days for military units, reducing combat power.