Warm-ups for military fitness testing: rapid evidence assessment of the literature

INTRODUCTION

Warm-up exercises are commonly used before exercise as a method to physiologically prepare for strenuous physical activity. Various warm-up exercises are often implemented but without scientific merit and, at times, may be detrimental to performance.

PURPOSE/OBJECTIVE

To date, no systematic reviews have examined the effectiveness of warm-up exercises for military physical fitness test (PFT) or combat fitness test (CFT). The purpose of this rapid evidence assessment of the literature was to examine the quantity, quality, and effectiveness of warm-up exercises for PFT and identify those that might increase PFT and/or CFT scores, as reported in the literature.

METHODS

Literature searches of randomized controlled trials were performed across various databases from database inception to May 2011. Methodological quality of included studies was assessed using the Scottish Intercollegiate Guidelines Network (SIGN) 50 criteria for randomized controlled trial designs, and studies were individually described. Subject matter experts summarized the results applicable or generalizable to military testing.

RESULTS

The search yielded a total of 1177 citations, with 37 fitting our inclusion criteria. Cardiovascular warm-ups increased sprint/running time, but dynamic stretching and dynamic warm-ups had the most positive outcome for the various exercise tests examined. Systematically, static stretching had no beneficial or detrimental effect on exercise performance but did improve range of movement exercises.

CONCLUSIONS

Selected warm-up exercise may increase PFT and possibly CFT scores. Further research is needed to investigate the efficacy of dynamic stretching and dynamic warm-ups.

Performance psychology as a key component of human performance optimization

The degree of psychological fitness will ultimately impact mission outcomes, so approaches to enhancing it are critical. Performance psychology is one important aspect of psychological fitness that fits into the holistic model of human performance optimization. This article delves into one component of performance psychology: how mental skill training can be applied to improve performance on mission-related tasks. Mental skills training provides added internal resources to help meet the extraordinary external demands that Special Operations Forces personnel can face. Relevance in terms of the demand-resource model and the positive psychology concept of flow are explained. The application of two specific mental skills--executing a goal-setting process and using mental imagery to rehearse technical, tactical, and strategic tasks--will be discussed by using the example of how to enhance performance when entering and clearing rooms.

An integrated approach for special operations

The Department of Defense (DoD) faces unprecedented challenges as the Nation confronts balancing a strong military to confront threats with the realities of diminishing financial resources. That each warfighter is a critical resource was underscored the Special Operations principal tenet "humans are more important than hardware." These challenges have popularized the term "human performance optimization" (HPO), which became ingrained in DoD around 2005. This article is the first in a new series relating to HPO, and we define the term and concept of HPO, describe other phrases used (e.g., performance enhancement; performance sustainment, performance restoration; and human performance modification). Last, we introduce an integrated model for HPO.

The 10 commandments of nutrition: 2014

The US Special Operations Command requires sound recommendations on nutrition to ensure optimal performance of Special Operations personnel. New information continues to emerge, and previous recommendations need to be modified as the evidence base continues to grow. The first 10 Commandments of Nutrition were published in the SEAL professional journal Full Mission Profile in 1992, published for the second time in this journal in 2005, and now revised a second time to reflect the newest science. Whether you are part of the Special Operations Forces (SOF) community or an athlete seeking to improve your performance, these are simple and helpful nutrition guidelines to follow.

Strategies for optimizing military physical readiness and preventing musculoskeletal injuries in the 21st century

With downsizing of the military services and significant budget cuts, it will be more important than ever to optimize the health and performance of individual service members. Musculoskeletal injuries (MSIs) represent a major threat to the health and fitness of Soldiers and other service members that degrade our nation's ability to project military power. This affects both financial (such as the economic burden from medical, healthcare, and disability costs) and human manpower resources (Soldiers medically unable to optimally perform their duties and to deploy). For example, in 2012, MSIs represented the leading cause of medical care visits across the military services resulting in almost 2,200,000 medical encounters. They also result in more disability discharges than any other health condition. Nonbattle injuries (NBIs) have caused more medical evacuations (34%) from recent theaters of operation than any other cause including combat injuries. Physical training and sports are the main cause of these NBIs. The majority (56%) of these injuries are the direct result of physical training. Higher levels of physical fitness protect against such injuries; however, more physical training to improve fitness also causes higher injury rates. Thus, military physical training programs must balance the need for fitness with the risks of injuries. The Army has launched several initiatives that may potentially improve military physical readiness and reduce injuries. These include the US Army Training and Doctrine Command's Baseline Soldier Physical Readiness Requirements and Gender Neutral Physical Performance Standards studies, as well as the reimplementation of the Master Fitness Trainer program and the Army Medical Command's Soldier Medical Readiness and Performance Triad Campaigns. It is imperative for military leaders to understand that military physical readiness can be enhanced at the same time that MSIs are prevented. A strategic paradigm shift in the military's approach to physical readiness policies is needed to avoid further degradation of warfighting capability in an era of austerity. We believe this can be best accomplished through leveraging scientific, evidence-based best practices by Army senior leadership which supports, prioritizes, and implements innovative, synchronized, and integrated human performance optimization/injury prevention policy changes.

Sleep as a component of the performance triad: the importance of sleep in a military population

OBJECTIVE

Sleep habits among military populations are problematic. Poor sleep hygiene occurs in parallel with the global increase in obesity and metabolic syndrome and contributes to a decrease in performance. The extent of sleep issues needs to be quantified to provide feedback for optimizing warfighter performance and readiness. This study assessed various health behaviors and habits of US Army Soldiers and their relationship with poor sleep quality by introducing a set of new questions into the Comprehensive Soldier and Family Fitness (CSF2) Global Assessment Tool (GAT).

METHODS

Subjects included 14,148 US Army Active, Reserve, and National Guard members (83.4% male) who completed the GAT, a self-report questionnaire that measures 4 fitness dimensions: social, family, emotional, and spiritual. Approximately 60 new questions, including ones on sleep quality, within the fifth CSF2 dimension (physical) were also answered. A sleep score was calculated from 2 questions validated in the Pittsburgh Insomnia Rating Scale (0 to 6).

RESULTS

Poor sleepers (5-6) were significantly (P<.001) more likely than good sleepers (0-1) to consider themselves in fair or poor health, be overweight or obese, and score in the lowest quartile of the emotional, social, family, and spiritual fitness dimensions. Additionally, poor sleepers were significantly (P<.001) less likely to have a healthy body mass index and waist circumference, eat breakfast 6 or more times a week, meet aerobic exercise and resistance training recommendations, and pass their Army Physical Fitness Test in the top quartile.

CONCLUSION

This study examined sleep quality in a group of military personnel and indicated significant associations between quality of sleep and physical performance, nutritional habits, measures of obesity, lifestyle behaviors and measures of psychosocial status. Targeted educational interventions and resources are needed to improve sleep patterns based on behaviors that can be most easily modified.

Nutrition as a component of the performance triad: how healthy eating behaviors contribute to soldier performance and military readiness

OBJECTIVE

Nutrition is a critical element of Soldier health and performance. Food choices, meal timing, and dietary intake behaviors contribute to nutritional fitness. The objectives of this study were to describe Soldier dietary behaviors and quantify the association between healthy eating behaviors and demographic, lifestyle, and psychosocial factors.

METHODS

The Comprehensive Soldier and Family Fitness Global Assessment Tool (GAT) assesses emotional, social, family, and spiritual fitness. In 2012, 57 pilot questions were added to the GAT to create a physical dimension that included nutrition assessments. Participants included 13,858 Active Duty, Reserve, and National Guard Soldiers: 83% male; 85% enlisted; a mean age of 28±9 years. A Healthy Eating Score (HES-5) was calculated from 5 questions assessing frequency of fruit, vegetable, whole grain, dairy, and fish intake (Cronbach α=0.81). Associations between HES-5 and other dietary habits, physical activity patterns, and GAT psychosocial dimension scores were examined.

RESULTS

Soldiers who ate breakfast regularly (6 times/week or more), drank 7 servings or more of water/day, and met weekly exercise recommendations were more likely to be in the highest HES-5 quartile than those who did not. Those who passed their Army Physical Fitness Test (APFT) in the top quartile were also more likely to report high HES-5 scores than those who failed (P<.001). Soldiers with healthy anthropometric measures and the highest emotional, social, family, and spiritual fitness scores were also more likely to be in the top HES-5 quartile than those with unhealthy measures and with the lowest fitness scores (P<.001).

CONCLUSION

The HES-5 may be a useful index for characterizing dietary intake behaviors. Healthy dietary intake behaviors are associated with all dimensions of health, physical fitness, and psychosocial status.

Physical fitness: a pathway to health and resilience

Various groups representing a number of different perspectives (for example, operational, architectural, community, institutional, and individual resilience) use the term resilience. We define resilience as the ability to withstand, recover, and grow in the face of stressors and changing demands. Physical fitness is one pathway toward resilience because it is associated with many traits and attributes required for resilience. In addition, physical fitness confers resilience because regular exercise and/or physical activity induces positive physiologic and psychological benefits, protects against the potential consequences of stressful events, and prevents many chronic diseases. This article presents a brief historical overview of the health-promoting effects of exercise and physical activity, followed by a discussion on the concept of hardiness and mental toughness and how they relate to resilience and physical fitness; how physical fitness promotes resilience; the clinical implications of a sedentary lifestyle; and the relevance of physical fitness and resilience to Army Medicine's Performance Triad.

An exploration of heat tolerance in mice utilizing mRNA and microRNA expression analysis

BACKGROUND

Individuals who rapidly develop hyperthermia during heat exposure (heat-intolerant) are vulnerable to heat associated illness and injury. We recently reported that heat intolerant mice exhibit complex alterations in stress proteins in response to heat exposure. In the present study, we further explored the role of genes and molecular networks associated with heat tolerance in mice.

METHODOLOGY

Heat-induced physiological and biochemical changes were assessed to determine heat tolerance levels in mice. We performed RNA and microRNA expression profiling on mouse gastrocnemius muscle tissue samples to determine novel biological pathways associated with heat tolerance.

PRINCIPAL FINDINGS

Mice (n = 18) were assigned to heat-tolerant (TOL) and heat-intolerant (INT) groups based on peak core temperatures during heat exposures. This was followed by biochemical assessments (Hsp40, Hsp72, Hsp90 and Hsf1 protein levels). Microarray analysis identified a total of 3,081 mRNA transcripts that were significantly misregulated in INT compared to TOL mice (p<0.05). Among them, Hspa1a, Dnajb1 and Hspb7 were differentially expressed by more than two-fold under these conditions. Furthermore, we identified 61 distinct microRNA (miRNA) sequences significantly associated with TOL compared to INT mice; eight miRNAs corresponded to target sites in seven genes identified as being associated with heat tolerance pathways (Hspa1a, Dnajb1, Dnajb4, Dnajb6, Hspa2, Hspb3 and Hspb7).

CONCLUSIONS

The combination of mRNA and miRNA data from the skeletal muscle of adult mice following heat stress provides new insights into the pathophysiology of thermoregulatory disturbances of heat intolerance.

Dietary supplements: physician knowledge and adverse event reporting

PURPOSE

Dietary supplement (DS) use among US military personnel is widespread. Many consume several different DS with multiple ingredients one or more times each week, representing a potential public health concern. The overall purpose of the study was to assess the knowledge and behaviors of health professionals and physicians regarding patterns of DS use and possible adverse events (AE) associated with DS use. We also determined how providers address the issue of DS with patients and evaluated provider knowledge regarding reporting systems.

METHODS

Two prospective, cross-sectional, web-based questionnaires were administered. First, health care providers who accessed the Natural Medicines Comprehensive Database to gather evidenced-based information on DS and herbal products were queried. Second, physicians who had graduated from the Uniformed Services University were sent a web-based questionnaire regarding DS knowledge, AE knowledge and reporting, and communication with patients about DS. The frequencies of responses were evaluated.

RESULTS

Although 60% of the military physicians who responded to the questionnaires believed they had observed AE in association with a DS, only 18% actually reported them. Three of four physician respondents (approximately 73%) did not know how or where to report AE associated with DS. The majority of physicians (66%) routinely asked most of their patients about DS use, and 65% did not have a reliable source of information for herbal and DS products.

CONCLUSIONS

Information gaps in DS information and AE reporting were identified. A centralized AE reporting system could serve to identify potentially harmful DS for further evaluation. Health professionals need to remain vigilant for AE associated with DS use and better informed on how to report these events.

Third-party certification of dietary supplements: prevalence and concerns

According to recent studies, over 50% of the general population (and nearly 70% of military personnel) report regular use of dietary supplements (DS). Military personnel may be at greater risk for adverse reactions to DS because of operational environments and stressors (extreme heat, altitude, or sleep deprivation) associated with military deployments and training. As a recent example, the Department of Defense placed a medical hold on all DS containing the ingredient 1,3-dimethylamylamine in response to several fatalities linked to the use of this product. This study investigated product certification for DS in military commissaries (grocery stores), exchanges (department stores), and civilian retail stores. Overall, only 12% of the available products were certified by an independent scientific agency. Consumers should be aware that most over-the-counter DS do not have independent certification of product integrity. Although "third-party certification" does not ensure DS safety or effectiveness, it is important that consumers and health care providers are made aware that such product screening takes place, to help patients make more informed decisions about the purchase and use of DS.

Tissue-specific upregulation of HSP72 in mice following short-term administration of alcohol

Oxidative stress and cellular injury have been implicated in induction of HSP72 by alcohol. We investigated the association between HSP72 induction and oxidative stress in mouse tissues following short-term administration of high doses of alcohol and caffeine alone or in combination. Adult male C57BL/6J mice were gavaged with vehicle, alcohol (∼1.7 g/kg/day), caffeine (∼44 mg/kg/day), or alcohol plus caffeine once daily for ten consecutive days. Upon completion of the treatments, tissues were collected for structural and biochemical analyses. Alcohol alone caused mild to moderate lesions in heart, liver, and gastrocnemius muscle. Similar structural changes were observed following administration of alcohol and caffeine combined. Alcohol administration also led to decreased glutathione levels in all three tissues and reduced plasma superoxide dismutase capacity. In contrast, alcohol and caffeine in combination reduced glutathione levels only in liver and gastrocnemius muscle and had no effect on plasma superoxide dismutase. Significant elevations in HSP72 protein and mRNA and in HSF1 protein levels were noted only in liver by alcohol alone or in combination with caffeine. No significant changes in morphology and HSP72 were detected in any tissues tested following administration of caffeine alone. These results suggest that a redox mechanism is involved in the structural impairment caused by short-term high-dose alcohol. Oxidative tissue injury by alcohol may not be associated with tissue HSP72 induction. Induction of HSP72 in liver by alcohol is mediated at both the transcriptional and translational levels.

ACSM and CHAMP summit on sickle cell trait: mitigating risks for warfighters and athletes

INTRODUCTION

An estimated 300 million people worldwide have sickle cell trait (SCT). Although largely benign, SCT has been associated with exertional rhabdomyolysis and exercise-related sudden death in warfighters/athletes (WA). The National Collegiate Athletic Association's policy to confirm a student athlete's SCT status during their preparticipation medical examination prompted reaction from some organizations regarding the rationale and ethical justification of the policy.

METHODS

On September 26 and 27, 2011, a summit, composed of military and civilian experts in sports medicine and SCT, was convened at the Uniformed Services University in Bethesda, MD. The expert panel was charged with two objectives: 1) to provide specific recommendations to further mitigate the apparent risk with strenuous exercise in WA with SCT and 2) to develop clinical guidelines to identify, treat, and return to duty/play WA suspected to have incurred nonfatal sickle cell collapse.

RESULTS

New terminology is introduced, areas of current controversy are explored, consensus recommendations for mitigating risk and managing the WA with SCT are reviewed, and important areas for future research are identified.

CONCLUSION

Further research is needed before conclusions can be drawn regarding the etiology of the increased death rate observed in WA with SCT, and the possibility exists that SCT is a surrogate for as yet another contributing factor for the unexplained deaths.

Consortium for Health and Military Performance and American College of Sports Medicine consensus paper on extreme conditioning programs in military personnel

A potential emerging problem associated with increasingly popularized extreme conditioning programs (ECPs) has been identified by the military and civilian communities. That is, there is an apparent disproportionate musculoskeletal injury risk from these demanding programs, particularly for novice participants, resulting in lost duty time, medical treatment, and extensive rehabilitation. This is a significant and costly concern for the military with regard to effectively maintaining operational readiness of the Force. While there are certain recognized positive aspects of ECPs that address a perceived and/or actual unfulfilled conditioning need for many individuals and military units, these programs have limitations and should be considered carefully. Moreover, certain distinctive characteristics of ECPs appear to violate recognized accepted standards for safely and appropriately developing muscular fitness and are not uniformly aligned with established and accepted training doctrine. Accordingly, practical solutions to improve ECP prescription and implementation and reduce injury risk are of paramount importance.

Functional movement screening: predicting injuries in officer candidates

PURPOSE

Functional movement screening (FMS) is a musculoskeletal assessment method that incorporates seven movements and yields an overall score based on movement quality. The objectives of this study were to document the distribution of scores and to determine whether FMS scores could predict injury in a large military cohort.

METHODS

A cohort of 874 Marine officer candidates were recruited, consented, completed demographic questionnaires, and had FMS performed during medical in-processing. Candidates were enrolled in either long-cycle (LC: 68 d; n = 427) or short-cycle (SC: 38 d; n = 447) training and followed up for injuries occurring in training.

RESULTS

The mean FMS score (score range = 0-21) among all candidates was 16.6 ± 1.7; approximately 10% of candidates had FMS scores ≤14. A score of ≤14 on the FMS predicted any injury with a sensitivity of 0.45 and a specificity of 0.71 and serious injury with a sensitivity of 0.12 and a specificity of 0.94. Both LC and SC cohorts demonstrated higher injury risk among candidates who had scores ≤14 compared with those with scores >14 (LC: risk ratio (RR) = 1.65, 95% confidence interval = 1.05-2.59, P = 0.03; SC: RR = 1.91, 95% confidence interval = 1.21-3.01, P < 0.01). Overall, 79.8% of persons with scores ≤14 were in the group with fitness scores <280 (/300), whereas only 6.6% of candidates in the group with fitness scores ≥280 had scores ≤14.

CONCLUSIONS

This was the first large-scale study performed in an active-duty military cohort to examine the utility of FMS during medical in-processing. Further work is warranted to evaluate FMS and the potential for injury prediction and prevention.