Insulin-like growth factor-I biocompartmentalization across blood, interstitial fluid and muscle, before and after 3 months of chronic resistance exercise.

This investigation examined the influence of 12-week ballistic resistance training programs on the IGF-I system in circulation, interstitial fluid, and skeletal muscle, at rest and in response to acute exercise. Seventeen college-aged subjects (11 women/6 men; 21.7 ± 3.7 yr) completed an acute ballistic exercise bout before and after the training program. Blood samples were collected pre-, mid-, and postexercise and analyzed for serum total IGF-I, free IGF-I, and IGF binding proteins (IGFBPs) 1-4. Dialysate and interstitial free IGF-I were analyzed in vastus lateralis (VL) interstitial fluid collected pre- and postexercise via microdialysis. Pre- and postexercise VL muscle biopsies were analyzed for IGF-I protein expression, IGF-I receptor phosphorylation (p-IGF-IR), and AKT phosphorylation (p-AKT). Following training, basal serum IGF-I, free IGF-I, IGFBP-2, and IGFBP-3 decreased whereas IGFBP-1 and IGFBP-4 increased. Training reduced basal dialysate and interstitial free IGF-I but had no effect on basal skeletal muscle IGF-I, p-IGF-IR, or p-AKT. Acute exercise elicited transient changes in IGF-I system concentrations and downstream anabolic signaling both pre- and posttraining; training did not affect this acute exercise response. Posttraining, acute exercise-induced changes in dialysate/interstitial free IGF-I were strongly correlated with the changes in intramuscular IGF-I expression, p-IGF-IR, and p-AKT. The divergent influence of resistance training on circulating/interstitial and skeletal muscle IGF-I demonstrates the importance of concurrent, multiple biocompartment analysis when examining the IGF-I system. As training elicited muscle hypertrophy, these findings indicate that IGF-I's anabolic effects on skeletal muscle are mediated by local, rather than systemic mechanisms.NEW & NOTEWORTHY In the first investigation to assess resistance training's effects on the IGF-I system in serum, interstitial fluid, and skeletal muscle, training decreased basal circulating and interstitial IGF-I but did not alter basal intramuscular IGF-I protein activity. Posttraining, acute exercise-induced interstitial IGF-I increases were strongly correlated with intramuscular IGF-I expression and signaling. These findings highlight the importance of multibiocompartment measurement when analyzing IGF-I and suggest that IGF-I's role in hypertrophic adaptations is locally mediated.

Models to predict injury, physical fitness failure and attrition in recruit training: a retrospective cohort study.

BACKGROUND: Attrition rate in new army recruits is higher than in incumbent troops. In the current study, we identified the risk factors for attrition due to injuries and physical fitness failure in recruit training. A variety of predictive models were attempted. METHODS: This retrospective cohort included 19,769 Army soldiers of the Australian Defence Force receiving recruit training during a period from 2006 to 2011. Among them, 7692 reserve soldiers received a 28-day training course, and the remaining 12,077 full-time soldiers received an 80-day training course. Retrieved data included anthropometric measures, course-specific variables, injury, and physical fitness failure. Multivariate regression was used to develop a variety of models to predict the rate of attrition due to injuries and physical fitness failure. The area under the receiver operating characteristic curve was used to compare the performance of the models. RESULTS: In the overall analysis that included both the 28-day and 80-day courses, the incidence of injury of any type was 27.8%. The 80-day course had a higher rate of injury if calculated per course (34.3% vs. 17.6% in the 28-day course), but lower number of injuries per person-year (1.56 vs. 2.29). Fitness test failure rate was significantly higher in the 28-day course (30.0% vs. 12.1%). The overall attrition rate was 5.2 and 5.0% in the 28-day and 80-day courses, respectively. Stress fracture was common in the 80-day course (n = 44) and rare in the 28-day course (n = 1). The areas under the receiver operating characteristic curves for the course-specific predictive models were relatively low (ranging from 0.51 to 0.69), consistent with "failed" to "poor" predictive accuracy. The course-combined models performed somewhat better than the course-specific models, with two models having AUC of 0.70 and 0.78, which are considered "fair" predictive accuracy. CONCLUSION: Attrition rate was similar between 28-day and 80-day courses. In comparison to the 80-day full course, the 28-day course had a lower rate of injury but a higher number of injuries per person-year and of fitness test failure. These findings suggest fitness level at the commencement of training is a critically important factor to consider when designing the course curriculum, particularly short courses.

U.S. Army Physical Demands Study: Differences in Physical Fitness and Occupational Task Performance Between Trainees and Active Duty Soldiers.

Canino, MC, Foulis, SA, Zambraski, EJ, Cohen, BS, Redmond, JE, Hauret, KG, Frykman, PN, and Sharp, MA. U.S. Army Physical Demands Study: Differences in physical fitness and occupational task performance between trainees and active duty soldiers. J Strength Cond Res 33(7): 1864-1870, 2019-U.S. Army initial entry training (IET) is designed to prepare trainees for the military environment and subsequent training, including specific programs to increase physical fitness to perform job-specific tasks to the minimal acceptable performance standard (MAPS). The aim of this study was to compare physical fitness and occupational task performance of trainees at the end of IET to that of active duty soldiers. One hundred seventy-nine male combat arms trainees at the end of IET and 337 male combat arms active duty soldiers performed a sandbag carry (SBC), casualty drag (CD), and move under direct fire (MUF). Physical fitness was assessed using Army Physical Fitness Test scores. A questionnaire was administered to determine frequency of task performance. Active duty soldiers compared with trainees were older (p < 0.01) and performed more push-ups (p < 0.01) and sit-ups (p < 0.01). Trainees performed the 2-mile run faster (p < 0.01). Ninety-four percent of trainees and 99% of active duty soldiers performed the 3 tasks to the MAPSs. Active duty soldiers performed significantly faster on both the SBC (p < 0.01) and CD (p < 0.01) and reported a higher task frequency on the SBC (p = 0.03) and CD (p < 0.01). No difference in MUF performance (p = 0.16) and task frequency (p = 0.13) was detected. Initial entry training seems to provide sufficient physical training as most trainees were able to meet the MAPSs; however, performance differences were still apparent between trainees and active duty soldiers. Additional practice performing the physically demanding tasks may help maximize performance on the physically demanding job requirements.

International consensus on military research priorities and gaps - Survey results from the 4th International Congress on Soldiers' Physical Performance.

OBJECTIVES: The objectives of this study were to identify perceived priorities related to military personnel's health and physical performance, among attendees at the 4th International Congress on Soldiers' Physical Performance (ICSPP), and to determine if perceived priorities had changed between the 3rd ICSPP survey held in 2014 and the 4th ICSPP survey held in 2017. DESIGN: Electronic survey. METHODS: Respondents were asked to grade priority areas on a Likert scale, and average ratings were used to rank priority areas. Responses to free text questions were analyzed qualitatively. Responses to the 4th ICSPP survey were described and compared to responses to the 3rd ICSPP survey. RESULTS: The 4th ICSPP survey respondents were a diverse group (40.6% military, 58.9% civilian). The two most important priority areas identified were physical demands in operational environments (mean score=4.41/5) and measuring physical performance/fitness (4.38/5), which were also the top two areas in the 3rd ICSPP survey. There was remarkable overlap in the rankings of priority areas between the two surveys. Sleep and nutrition were emerging priority areas and were perceived as relatively more important in the 4th ICSPP survey compared to the 3rd ICSPP survey. The greatest perceived emerging threat was resilience/psychological fitness of recruits (4.16/5). Physiological status monitoring (2.79/4) was identified as the most important technology. CONCLUSIONS: Despite the diverse backgrounds of the respondents, there was a clear continuing consensus about perceived important priority areas influencing military personnel's health and physical performance. Soldier resiliency and assessment of physiological status were research topics identified as top priorities.

The Relationship Between Soldier Performance on the Two-Mile Run and the 20-m Shuttle Run Test.

Background: The 20-m shuttle run test (MSRT) is a common field test used to measure aerobic fitness in controlled environments. The U.S. Army currently assesses aerobic fitness with the two-mile run (TMR), but external factors may impact test performance. The aim of this study is to examine the relationship between the Army Physical Fitness Test TMR performance and the MSRT in military personnel. Methods: A group of 531 (403 males and 128 females) active duty soldiers (age: 24.0 ± 4.1 years) performed the MSRT in an indoor facility. Heart rate was monitored for the duration of the test. Post-heart rate and age-predicted maximal heart rate were utilized to determine near-maximal performance on the MSRT. The soldiers provided their most recent Army Physical Fitness Test TMR time (min). A Pearson correlation and multiple linear regression analyses were performed to examine the relationship between TMR time (min) and MSRT score (total number of shuttles completed). The study was approved by the Human Use Review Committee at the U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts. Findings: A significant, negative correlation exists between TMR time and MSRT score (r = -0.75, p < 0.001). Sex and MSRT score significantly predicted TMR time (adjusted R2 = 0.65, standard error of estimate = 0.97, p < 0.001) with a 95% ratio limits of agreement of ±12.6%. The resulting equation is: TMR = 17.736-2.464 × (sex) - 0.050 × (MSRT) - 0.026 × (MSRT × sex) for predicted TMR time. Males equal zero, females equal one, and MSRT score is the total number of shuttles completed. Discussion: The MSRT is a strong predictor of the TMR and should be considered as a diagnostic tool when assessing aerobic fitness in active duty soldiers.

U.S. Army physical demands study: Identification and validation of the physically demanding tasks of combat arms occupations.

OBJECTIVES: In 2013, the U.S. Army began developing physical tests to predict a recruit's ability to perform the critical, physically demanding tasks (CPDTs) of combat arms jobs previously not open to women. The purpose of this paper is to describe the methodology and results of analyses of the accuracy and inclusiveness of the critical physically demanding task list. While the job analysis included seven combat arms jobs, only data from the 19D Cavalry Scout occupation are presented as the process was similar for all seven jobs. DESIGN: Job analysis METHODS: As the foundation, senior subject matter experts from each job reviewed materials and reached consensus on the CPDTs and performance standards for each job. The list was reviewed by Army leadership and provided to the researchers. The job analysis consisted of reviewing job and task related documents and field manuals, observing >900 soldiers performing the 32 CPDTs, conducting two focus groups for each job, and analyzing responses to widely distributed job analysis questionnaires. RESULTS: Of the 32 CPDTs identified for seven combat jobs, nine were relevant to 19D soldiers. Focus group discussions and job analysis questionnaire results supported the tasks and standards identified by subject matter experts while also identifying additional tasks. CONCLUSIONS: The tasks identified by subject matter experts were representative of the physically demanding aspects of the 19D occupation.

U.S. Army Physical Demands Study: Development of the Occupational Physical Assessment Test for Combat Arms soldiers.

OBJECTIVES: The United States Army sought to create a legally defensible, scientifically validated physical pre-employment screening test. The purpose of this study was to identify a single combination of predictor tests that would predict physical performance on all of the criterion measure task simulations relevant to the Combat Arms military occupational specialties. DESIGN: Concurrent validation. METHODS: Data from 838 (608 males, 230 females) soldiers who completed both the criterion measure task simulations of a military occupational specialty and up to 14 predictor tests were used in the development of the test batteries. Stepwise regressions were used to identify test batteries that significantly predicted performance on the criterion measure task simulations of the military occupational specialties. RESULTS: Three test batteries were developed based on different subsets of the predictor tests: Test Battery 1 consisted of the medicine ball put, squat lift, beep test, standing long jump, and arm ergometer (adjusted R2=0.80-0.85, p<0.01); Test Battery 2 consisted of the medicine ball put, squat lift, beep test, and standing long jump (adjusted R2=0.79-0.80, p<0.01); and Test Battery 3 consisted of the standing long jump, 1-minute push-ups, 1-minute sit-ups, 300m sprint, and Illinois agility test (adjusted R2=0.55-0.71, p<0.01). CONCLUSIONS: Test Battery 2 was selected as the Army's Occupational Physical Assessment Test. It was highly predictive of performance of the Combat Arms military occupational specialties, required no complex equipment, and covered a range of physical fitness domains.

U.S. Army Physical Demands Study: Reliability of Simulations of Physically Demanding Tasks Performed by Combat Arms Soldiers.

Foulis, SA, Redmond, JE, Frykman, PN, Warr, BJ, Zambraski, EJ, and Sharp, MA. U.S. Army physical demands study: reliability of simulations of physically demanding tasks performed by combat arms soldiers. J Strength Cond Res 31(12): 3245-3252, 2017-Recently, the U.S. Army has mandated that soldiers must successfully complete the physically demanding tasks of their job to graduate from their Initial Military Training. Evaluating individual soldiers in the field is difficult; however, simulations of these tasks may aid in the assessment of soldiers' abilities. The purpose of this study was to determine the reliability of simulated physical soldiering tasks relevant to combat arms soldiers. Three cohorts of ∼50 soldiers repeated a subset of 8 simulated tasks 4 times over 2 weeks. Simulations included: sandbag carry, casualty drag, and casualty evacuation from a vehicle turret, move under direct fire, stow ammunition on a tank, load the main gun of a tank, transferring ammunition with a field artillery supply vehicle, and a 4-mile foot march. Reliability was assessed using intraclass correlation coefficients (ICCs), standard errors of measurement (SEMs), and 95% limits of agreement. Performance of the casualty drag and foot march did not improve across trials (p > 0.05), whereas improvements, suggestive of learning effects, were observed on the remaining 6 tasks (p ≤ 0.05). The ICCs ranged from 0.76 to 0.96, and the SEMs ranged from 3 to 16% of the mean. These 8 simulated tasks show high reliability. Given proper practice, they are suitable for evaluating the ability of Combat Arms Soldiers to complete the physical requirements of their jobs.

Widespread Use of Prescription Nonsteroidal Anti-Inflammatory Drugs Among U.S. Army Active Duty Soldiers.

INTRODUCTION: Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used to treat pain and inflammation by inhibiting prostaglandin synthesis. There is a high incidence of musculoskeletal injuries in the military, which would validate the widespread use of NSAIDs. This study determined the amount and specific types of NSAIDs being prescribed to U.S. Army active duty soldiers. METHODS AND MATERIALS: This study was a quantitative study which utilized an existing database of de-identified data; therefore, institutional review board approval was not required. Data pertaining to NSAID prescriptions issued to active duty soldiers for fiscal years 2006, 2011, and 2014 were obtained from the Department of Defense Pharmacy Data Transactions Service data warehouse, which contains all outpatient prescriptions. The data include the number of soldiers receiving NSAID prescriptions (i.e., utilizers) as well as the number of prescriptions given for each specific NSAID. RESULTS: In 2006, 2011, and 2014, the numbers of active duty utilizers were 348,031, 435,364, and 418,579, respectively. For the entire active duty Army, the percentage of soldiers who were receiving NSAID prescriptions was approximately 69% in 2006, 77% in 2011, and 82% in 2014. The number of NSAIDs prescribed was 740,090 in 2006; 898,291 in 2011; and 857,964 in 2014. Celecoxib, the only cyclooxygenase-2 inhibitor prescribed in the United States accounted for 2.4% of these NSAID prescriptions in 2006, 6.3% in 2011, and 7.1% in 2014. During all 3 years, the number of prescriptions filled was almost twice the number of utilizers, indicating that many individuals were receiving more than one prescription. Female soldiers received almost twice the number of prescriptions per individual as male soldiers. The use of over-the-counter NSAIDs, which are widely available, was not accounted for in this study; therefore, total NSAID use is likely higher than reported. CONCLUSION: The vast majority of U.S. Army active duty soldiers are being prescribed NSAIDs. These data raise concerns because of the potential adverse effects that NSAIDs have on gastrointestinal, renal, and cardiovascular function, as well as bone health. Additional studies are warranted to determine the actual amounts of NSAIDs being used and the specific conditions for which they are being prescribed.

Does high muscle temperature accentuate skeletal muscle injury from eccentric exercise?

Hyperthermia is suspected of accentuating skeletal muscle injury from novel exercise, but this has not been well studied. This study examined if high muscle temperatures alters skeletal muscle injury induced by eccentric exercise (ECC). Eight volunteers (age, 22.5 ± 4.1 year; height, 169.5 ± 10.8 cm; body mass, 76.2 ± 12.6 kg), serving as their own control, and who were not heat acclimatized, completed two elbow flexor ECC trials; in one trial the biceps were heated >40°C (HEAT) and in the other trial there was no heating (NON). HEAT was applied with shortwave diathermy (100 W) for 15 min immediately before the first ECC bout and for 2 min in between each bout. Individuals were followed for 10 days after each ECC session, with a 6-week washout period between arms. The maximal voluntary isometric contraction decreased by 41 ± 17% and 46 ± 20% in the NON and HEAT trials, respectively. Bicep circumference increased by 0.07 ± 0.08 mm (4%, P = 0.04) and relaxed range of motion decreased by 11.5 ± 8.2° (30%, P < 0.001) in both trials. Serum creatine kinase peaked 72-h following ECC (NON: 6289 ± 10407; HEAT: 5486 ± 6229 IU L(-1), 38-fold increase, P < 0.01) as did serum myoglobin (NON: 362 ± 483; HEAT: 355 ± 373 µg L(-1), 13-fold increase, P < 0.03). Plasma HSP 70 was higher (P < 0.02) in HEAT after 120-h of recovery. There were no differences between treatments for plasma HSP27 and interleukins 1ß, 6, and 10. The results indicate that >40°C muscle temperature does not alter skeletal muscle injury or functional impairments induced by novel ECC.

International Research Consensus: Identifying Military Research Priorities and Gaps.

A multidisciplinary survey was administered to military performance researchers attending the Third International Conference on Soldier Physical Performance to obtain their opinions of the priority levels and importance of research topics related to soldier health and determinants of soldier physical performance. Respondents included 140 individuals from 22 different countries, of which 96% had at least a graduate degree and 79% were associated with a military organization. The top 5 highest importance/priority research topics were (a) physical demands in operational environments, (b) measuring physical performance/fitness, (c) musculoskeletal injury mitigation programs, (d) physical employment standards, and (e) physical strength-training programs. Of what individuals thought were their most important topics, 50% reported these were not currently being researched because of higher priorities, insufficient funding, or the lack of scientific expertise. A theme analysis of research-topic areas that were important and not being researched indicated that physical employment standards and physical training studies related to soldiers' health and performance are knowledge gaps. Although these experienced researchers had diverse backgrounds and were working on a wide array of research topics, there was a surprisingly clear consensus on what they thought were important topics that needed to be addressed in common between countries or militaries.

Spot Urine Concentrations Should Not be Used for Hydration Assessment: A Methodology Review.

A common practice in sports science is to assess hydration status using the concentration of a single spot urine collection taken at any time of day for comparison against concentration (specific gravity, osmolality, color) thresholds established from first morning voids. There is strong evidence that this practice can be confounded by fluid intake, diet, and exercise, among other factors, leading to false positive/negative assessments. Thus, the purpose of this paper is to provide a simple explanation as to why this practice leads to erroneous conclusions and should be curtailed in favor of consensus hydration assessment recommendations.

IGF-I measurement across blood, interstitial fluid, and muscle biocompartments following explosive, high-power exercise.

Insulin-like growth factor-I (IGF-I) resides across different biocompartments [blood, interstitial fluid (ISF), and muscle]. Whether circulating IGF-I responses to exercise reflect local events remains uncertain. We measured the IGF-I response to plyometric exercise across blood, ISF, and muscle biopsy from the vastus lateralis. Twenty volunteers (8 men, 12 women, 22 ± 1 yr) performed 10 sets of 10 plyometric jump repetitions at a 40% 1-repetition maximum. Blood, ISF, and muscle samples were taken pre- and postexercise. Circulating IGF-I increased postexercise: total IGF-I (preexercise = 546 ± 42, midexercise = 585 ± 43, postexercise = 597 ± 45, +30 = 557 ± 42, +60 = 536 ± 40, +120 = 567 ± 42 ng/ml; midexercise, postexercise, and +120 greater than preexercise, P < 0.05); Free IGF-I (preexercise = 0.83 ± 0.09, midexercise = 0.78 ± 0.10, postexercise = 0.79 ± 0.11, +30 = 0.93 ± 0.10, +60 = 0.88 ± 0.10, + 120 = 0.91 ± 0.11 ng/ml; +30 greater than all other preceding time points, P < 0.05). No exercise-induced changes were observed for ISF IGF-I (preexercise = 2.35 ± 0.29, postexercise = 2.46 ± 0.35 ng/ml). No changes were observed for skeletal muscle IGF-I protein, although IGF-I mRNA content increased ∼40% postexercise. The increase in circulating total and free IGF-I was not correlated with increases in ISF IGF-I or muscle IGF-I protein content. Our data indicate that exercise-induced increases in circulating IGF-I are not reflective of local IGF-I signaling.

Effects of quercetin supplementation on markers of muscle damage and inflammation after eccentric exercise.

The flavonoid quercetin is purported to have potent antioxidant and anti-inflammatory properties. This study examined if quercetin supplementation attenuates indicators of exercise-induced muscle damage in a double-blind laboratory study. Thirty healthy subjects were randomized to quercetin (QU) or placebo (PL) supplementation and performed 2 separate sessions of 24 eccentric contractions of the elbow flexors. Muscle strength, soreness, resting arm angle, upper arm swelling, serum creatine kinase (CK) activity, plasma quercetin (PQ), interleukin-6 (IL-6), and C-reactive protein (CRP) were assessed before and for 5 d after exercise. Subjects then ingested nutrition bars containing 1,000 mg/d QU or PL for 7 d before and 5 d after the second exercise session, using the opposite arm. PQ reached 202 ± 52 ng/ml after 7 d of supplementation and remained elevated during the 5-d postexercise recovery period (p < .05). Subjects experienced strength loss (peak = 47%), muscle soreness (peak = 39 ± 6 mm), reduced arm angle (-7° ± 1°), CK elevations (peak = 3,307 ± 1,481 U/L), and arm swelling (peak = 11 ± 2 mm; p < .0001), indicating muscle damage and inflammation; however, differences between treatments were not detected. Eccentric exercise did not alter plasma IL-6 (peak = 1.9 pg/ml) or CRP (peak = 1.6 mg/L) relative to baseline or by treatment. QU supplementation had no effect on markers of muscle damage or inflammation after eccentric exercise of the elbow flexors.

Prevention and rehabilitation of musculoskeletal injuries during military operations and training.

Injuries are a major impacting factor for a military organization. Injuries may be the result of direct combat, or noncombat, and may be incurred during deployment, other military operations and training. The impact of injuries is the loss of manpower (e.g., lost duty days), medical costs for treatment, and the influence that an injury may have on an individual's quality of life. To address this issue, it is essential to understand the types of injuries that are occurring, and the mechanisms responsible for those injuries, to develop strategies to reduce injury incidence and to allocate the resources required for rehabilitation to return the individual to duty. This article will review the most common medical injury being incurred by our present warfighter; namely, musculoskeletal injuries (MSIs). The number, types, and causal mechanisms of MSIs will be reviewed. Risk factors for MSIs will be identified and the various interventions being used to prevent or mitigate the severity of MSIs will be discussed. Lastly, the programs that have been developed within the U.S. Department of Defense and the U.S. Army for the assessment, care, and rehabilitation of the most severe MSIs incurred while deployed will be described.

Adenosine A3 receptor stimulation reduces muscle injury following physical trauma and is associated with alterations in the MMP/TIMP response.

We have previously demonstrated that in response to traumatic injury in skeletal muscle, there is a dysregulation of the matrix metalloproteases (MMPs) and their inhibitors (TIMPs), a response hypothesized to interfere with proper skeletal muscle regeneration. Moreover, we have shown that pharmacological activation of the adenosine A(3) receptor by Cl-IBMECA in skeletal muscle can protect against ischemia-reperfusion and eccentric exercise injury. However, the mechanism by which Cl-IBMECA protects muscle tissue is poorly defined. This study evaluated the effects of Cl-IBMECA on MMP/TIMP expression in skeletal muscle and tested the hypothesis that adenosine A(3) receptor-stimulated protection of skeletal muscle following traumatic injury is associated with a blunting of MMPs involved in inflammatory processes and collagen degradation, and an increase in MMPs associated with extracellular matrix remodeling. Sixty C57BL/6J male mice were injected with Cl-IBMECA (n = 30) or a vehicle (n = 30), and Evans blue dye. Injury was induced by applying a cold steel probe (-79°C) to the tibialis anterior (TA) muscle for 10 s. TA muscles from uninjured and injured legs were collected 3, 10, and 24 h postinjury for analysis of muscle injury and MMP/TIMP mRNA and protein levels. Twenty-four hours postinjury, 56.8% of the fibers were damaged in vehicle-treated mice vs. 35.4% in Cl-IBMECA-treated mice (P = 0.02). Cl-IBMECA treatment reduced membrane type 1 (MT1)-MMP, MMP-3, MMP-9, and TIMP-1 mRNA expression 2- to 20-fold compared with vehicle-treated mice (P < 0.05). Cl-IBMECA decreased protein levels of latent/shed MT1-MMP 23-2,000%, respectively, 3-10 h postinjury. In Cl-IBMECA-treated mice, latent MMP-2 was decreased 20% 3 h postinjury, active MMP-3 was decreased 64% 3 h postinjury, and latent/active MMP-9 was decreased 417,631% 3 h postinjury and 20% 10 h postinjury. Protein levels of active MMP-2 and latent MMP-3 were increased 25% and 74% 3 h postinjury, respectively. The present study elucidates a new protective role of adenosine A(3) receptor stimulation in posttraumatic skeletal muscle injury.

United States Army Research Institute of Environmental Medicine: Warfighter research focusing on the past 25 years.

The United States Army Research Institute of Environmental Medicine (USARIEM) celebrated its 50th anniversary on July 1, 2011. This article reviews its history, evolution, and transition of its research programs as well as its scientific and military accomplishments, emphasizing the past 25 yr. During the 1990s, USARIEM published a series of pocket guides providing guidance for sustaining Warfighter health and performance in Southwest Asia, Somalia, the former Republic of Yugoslavia, Rwanda, and Haiti. Issues identified during Operation Desert Storm elicited research that improved nutritional guidelines for protracted desert operations; safer use of nuclear, chemical, and biological protective clothing; equipment, development, and fielding of efficient microclimate cooling systems; and effective evaluation of pharmaceuticals to protect soldiers from chemical and biological threats. During the first decade of the 21st century, USARIEM and the Department of the Army published official medical/performance doctrines for operations in the heat and cold and at high altitude. The current Global War on Terrorism focused research to improve doctrines for hot, cold, and high-altitude operations, reduce musculoskeletal training injuries, provide improved field nutrition, more efficient planning for operational water requirements, and improve both military clothing and materiel. This article also describes the critically important interactions and communications between USARIEM and deployed units and the benefits to Warfighters from this association. This report presents USARIEM's unique and world-class facilities, organizational changes, scientific and support personnel, and major research accomplishments, including the publication of 2,200 scientific papers over the past 25 yr.

Comparison of body fat estimates using 3D digital laser scans, direct manual anthropometry, and DXA in men.

OBJECTIVES: The purpose of this study was to assess the feasibility of utilizing three dimensional whole body laser surface scanning (3DS) to obtain specific anthropometric measurements to estimate percent body fat (BF). METHODS: Percent BF estimates from 37 male volunteers, of age 18-62 yr, were determined by inputting manual anthropometric (MA) and 3DS anthropometric measurements into the current Army BF prediction equation for males. The results were compared with each other and to BF values from Dual Energy X-ray Absorptiometry (DXA), employed as a reference method. RESULTS: Mean percent BF estimates (+/-SD) derived from MA, 3DS and from DXA were 18.4(+/-3.8), 18.8(+/-3.9), and 18.9(+/-4.7), respectively. Analysis of Variance tests revealed no statistical difference between the mean values. Correlation analysis comparing MA and 3DS derived percent BF estimates to each other and to those measured by DXA revealed moderate to strong Pearson correlation coefficients (r), small to moderate standard errors of the estimate (SEE), and were statistically significant (p < 0.05). CONCLUSIONS: Correlation coefficients and SEE results for this sample were: (1) DXA vs 3DS; r = 0.74, SEE = 3.2, (2) MA vs DXA; r = 0.82, SEE = 2.8, and (3) MA vs 3DS; r = 0.96, SEE = 1.0. Lin's concordance analysis, including Bland-Altman limits of agreement (LOA), revealed statistically significant measurement agreement among the three measurement modalities (p < 0.05). The application of 3DS scanning to estimate percent BF from commonly used anthropometric measurements are in close agreement with BF estimates derived from analogous MA measurements and from DXA scanning.

Adenosine A(3) receptor stimulation induces protection of skeletal muscle from eccentric exercise-mediated injury.

Effective therapy to reduce skeletal muscle injury associated with severe or eccentric exercise is needed. The purpose of this study was to determine whether adenosine receptor stimulation can mediate protection from eccentric exercise-induced muscle injury. Downhill treadmill exercise (-15 degrees ) was used to induce eccentric exercise-mediated skeletal muscle injury. Experiments were conducted in both normal wild-type (WT) mice and also in beta-sarcoglycan knockout dystrophic mice, animals that show an exaggerated muscle damage with the stress of exercise. In the vehicle-treated WT animals, eccentric exercise increased serum creatine kinase (CK) greater than 3-fold to 358.9 +/- 62.7 U/l (SE). This increase was totally abolished by stimulation of the A(3) receptor. In the dystrophic beta-sarcoglycan-null mice, eccentric exercise caused CK levels to reach 55,124 +/- 5,558 U/l. A(3) receptor stimulation in these animals reduced the CK response by nearly 50%. In the dystrophic mice at rest, 10% of the fibers were found to be damaged, as indicated by Evans blue dye staining. While this percentage was doubled after exercise, A(3) receptor stimulation eliminated this increase. Neither the A(1) receptor agonist 2-chloro-N(6)-cyclopentyladenosine (0.05 mg/kg) nor the A(2A) receptor agonist 2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxamidoadenosine (0.07 mg/kg) protected skeletal muscle from eccentric exercise injury in WT or dystrophic mice. The protective effect of adenosine A(3) receptor stimulation was absent in mice, in which genes for phospholipase C beta2/beta3 (PLCbeta2/beta3) and beta-sarcoglycan were deleted. The present study elucidates a new protective role of the A(3) receptor and PLCbeta2/beta3 and points to a potentially effective therapeutic strategy for eccentric exercise-induced skeletal muscle injury.

CCL2 and CCR2 polymorphisms are associated with markers of exercise-induced skeletal muscle damage.

Novel eccentric (lengthening contraction) exercise typically results in muscle damage, which manifests as prolonged muscle dysfunction, delayed onset muscle soreness, and leakage of muscle proteins into circulation. There is a large degree of variability in the damage response of individuals to eccentric exercise, with higher responders at risk for potentially fatal rhabdomyolysis. We hypothesized that single nucleotide polymorphisms (SNPs) in chemokine ligand 2 (CCL2) and its receptor chemokine receptor 2 (CCR2) associate with the high degrees of variability in the muscle damage response. We based this hypothesis on CCL2's roles in macrophage and satellite cell signaling in injured muscle. DNA was obtained from 157 untrained men and women following maximal eccentric exercise. Strength loss, soreness, serum creatine kinase (CK), and myoglobin levels before and during recovery from a single exercise bout were tested for association with 16 SNPs in CCL2 and CCR2. The rare alleles for rs768539 and rs3918358 (CCR2) were significantly (P<0.05) associated with lower preexercise strength in men, whereas CCL2 SNPs (rs13900, rs1024611, and rs1860189) and CCR2 (rs1799865) were associated with altered preexercise CK levels in women. During recovery, the rs3917878 genotype (CCL2) was associated with attenuated strength recovery in men and an elevated CK response in women. CCR2 variants were associated with slower strength recovery in women (rs3918358) and elevated soreness (rs1799865) across all subjects. In summary, we found that SNPs in CCL2 and CCR2 are associated with exercise-induced muscle damage and that the presence of certain variants may result in an exaggerated damage response to strenuous exercise.