Ryan Steelman

A systematic review of the effects of physical training on load carriage performance.

Knapik, JJ, Harman, EA, Steelman, RA, and Graham, BS. A systematic review of the effects of physical training on load carriage performance. J Strength Cond Res 26(2): 585–597, 2012—Soldiers are often required to carry heavy loads during military operations. This article reports on a systematic literature review examining the influence of physical training on load carriage performance. Several literature databases, reference lists, and other sources were explored to find studies that quantitatively examined the effects of physical training on the time taken for individuals to complete a set distance carrying an external load, with the majority of the load contained in a backpack. Effect sizes (Cohens d statistic) were used in meta-analyses to examine the changes in load carriage performance after various modes of physical training. Effect sizes quantified training-related changes in terms of SD units. Ten original research studies met the review criteria. Meta-analysis indicated that large training effects (≥0.8SD units) were apparent when progressive resistance training was combined with aerobic training and when that training was conducted at least 3 times per week, over at least 4 weeks. When progressive load-carriage exercise was part of the training program, much larger training effects were evident (summary effect size [SES] = 1.7SD units). Field-based training that combined a wide variety of training modes and included progressive load-carriage exercise was also very effective in improving load carriage performance (SES = 1.1SD units). Aerobic training alone or resistance training alone had smaller and more variable effects, depending on the study. This review indicates that combinations of specific modes of physical training can substantially improve load carriage performance.

A systematic review and meta-analysis on the prevalence of dietary supplement use by military personnel

BackgroundAlthough a number of studies have been conducted on the prevalence of dietary supplement (DS) use in military personnel, these investigations have not been previously summarized. This article provides a systematic literature review of this topic.MethodsLiterature databases, reference lists, and other sources were searched to find studies that quantitatively examined the prevalence of DS use in uniformed military groups. Prevalence data were summarized by gender and military service. Where there were at least two investigations, meta-analysis was performed using a random model and homogeneity of the prevalence values was assessed.ResultsThe prevalence of any DS use for Army, Navy, Air Force, and Marine Corps men was 55%, 60%, 60%, and 61%, respectively; for women corresponding values were 65%, 71%, 76%, and 71%, respectively. Prevalence of multivitamin and/or multimineral (MVM) use for Army, Navy, Air Force, and Marine Corps men was 32%, 46%, 47%, and 41%, respectively; for women corresponding values were 40%, 55%, 63%, and 53%, respectively. Use prevalence of any individual vitamin or mineral supplement for Army, Navy, Air Force, and Marine Corps men was 18%, 27%, 25%, and 24%, respectively; for women corresponding values were 29%, 36%, 40%, and 33%, respectively. Men in elite military groups (Navy Special Operations, Army Rangers, and Army Special Forces) had a use prevalence of 76% for any DS and 37% for MVM, although individual studies were not homogenous. Among Army men, Army women, and elite military men, use prevalence of Vitamin C was 15% for all three groups; for Vitamin E, use prevalence was 8%, 7%, and 9%, respectively; for sport drinks, use prevalence was 22%, 25% and 39%, respectively. Use prevalence of herbal supplements was generally low compared to vitamins, minerals, and sport drinks, ≤5% in most investigations.ConclusionsCompared to men, military women had a higher use prevalence of any DS and MVM. Army men and women tended to use DSs and MVM less than other service members. Elite military men appeared to use DSs and sport drinks more than other service members.

A prospective investigation of injury incidence and injury risk factors among army recruits in military police training

BackgroundUnited States Army military police (MP) training is a 19-week course designed to introduce new recruits to basic soldiering skills, Army values and lifestyle, and law enforcement skills and knowledge. The present investigation examined injury rates and injury risk factors in MP training.MethodsAt the start of training, 1,838 male and 553 female MP recruits were administered a questionnaire containing items on date of birth, height, weight, tobacco use, prior physical activity, injury history, and menstrual history. Injuries during training were obtained from electronic medical records and the training units provided data on student graduation and attrition.ResultsSuccessfully graduating from the course were 94.3% of the men and 83.7% of the women. Experiencing at least one injury during training were 34.2% of the men and 66.7% of the women (risk ratio (women/men) = 1.95, 95% confidence interval = 1.79-2.13). Recruits were at higher injury risk if they reported that they were older, had smoked in the past, or had performed less frequent exercise or sports prior to MP training. Men were at higher injury risk if they reported a prior injury and women were at higher risk if they reported missing at least six menstrual cycles in the last year or had previously been pregnant.ConclusionThe present investigation was the first to identify injury rates and identify specific factors increasing injury risk during MP training.

A prospective investigation of injury incidence and risk factors among army recruits in combat engineer training

BackgroundUnited States Army combat engineer (ENG) training is an intense 14-week course designed to introduce new recruits to basic soldiering activities, Army values and lifestyle, and engineering skills and knowledge. The present investigation examined injury rates and injury risk factors in ENG training.MethodsAt the start of their training, 1,633 male ENG recruits were administered a questionnaire containing items on date of birth, height, weight, tobacco use, prior physical activity, and injury history. Injuries during training were obtained from electronic medical records and the training units provided data on student graduation and attrition. Risk factors were identified using Cox regression.ResultsNinety-two percent of the recruits successfully graduated from the course and 47% of the recruits experienced one or more injuries during training. Univariate Cox regression demonstrated that recruits were at higher injury risk if they reported that they were older, had a higher or lower body mass index, had smoked in the past, had performed less exercise (aerobic or muscle strength) or sports prior to ENG training, had experienced a previous time-loss lower limb injury (especially if they had not totally recovered from that injury), or had a lower educational level.ConclusionsThe present investigation was the first to identify injury rates and identify specific factors increasing injury risk during ENG training. The identified risk factors provide a basis for recommending future prevention strategies.

Prevalence, Adverse Events, and Factors Associated with Dietary Supplement and Nutritional Supplement Use by US Navy and Marine Corps Personnel

BACKGROUND About 50% of Americans and 60% to 70% of US military personnel use dietary supplements, some of which have been associated with adverse events (AEs). Nutritional supplements like sport drinks and sport bars/gels are also commonly used by athletes and service members. Previous dietary supplement and nutritional supplement surveys were conducted on Army, Air Force, and Coast Guard personnel. OBJECTIVE The aim of this cross-sectional study was to investigate dietary and nutritional supplement use in Navy and Marine Corps personnel, including the prevalence, types, factors associated with use, and AEs. DESIGN A random sample of 10,000 Navy and Marine Corps personnel were contacted. Service members were asked to complete a detailed questionnaire describing their personal characteristics, supplement use, and AEs experienced. RESULTS In total, 1,708 service members completed the questionnaire during August through December 2014, with 1,683 used for analysis. Overall, 73% reported using dietary supplements one or more times per week. The most commonly used dietary supplements (used one or more times per week) were multivitamins/multiminerals (48%), protein/amino acids (34%), combination products (33%), and individual vitamins and minerals (29%). About 31% of service members reported using five or more dietary supplements. Sport drinks and sport bars/gels were used by 45% and 23% of service members, respectively. Monthly expenditures on dietary supplements averaged

Activities Associated With Injuries in Initial Entry Training

39; 31% of service members spent ≥

Military parachuting injuries, associated events, and injury risk factors

50/mo. Multivariate logistic regression modeling indicated that female sex (women/men; odds ratio [OR]=1.76, 95% CI 1.32 to 2.36), higher educational level (college degree/no college degree; OR=2.23, 95% CI 1.62 to 3.30), higher body mass index (calculated as kg/m(2)) (≥30/<25; OR=1.67, 95% CI 1.06 to 2.63), and a greater amount of resistance training (≥271/0 to 45 min/week; OR=2.85, 95% CI 1.94 to 4.17) were associated with dietary supplement use. Twenty-two percent of dietary supplement users and 6% of nutritional supplement users reported one or more AEs. For combination products alone, 29% of users reported one or more AEs. CONCLUSIONS The prevalence of dietary supplement use in Navy and Marine Corps personnel was considerably higher than reported in civilian investigations for almost all types of dietary supplements, although similar to most other military services. Factors associated with dietary supplement use were similar to those reported in previous military and civilian investigations. Prevalence of self-reported AEs was very high, especially for combination products.

Physical Training in Boots and Running Shoes: A Historical Comparison of Injury Incidence in Basic Combat Training

Previous studies have not reported activities associated with injuries in initial entry training (IET) because these data were seldom available in medical records and not contained in electronic databases. This investigation obtained activities associated with outpatient encounters in IET recorded by primary medical care providers at Fort Leonard Wood, Missouri. Data were entered into a standard database that included fields for diagnosis and activity associated with the injury. Fifty percent of the new injury encounters (i.e., exclusive of follow-ups) were not associated with a specific event but were reported as having a gradual onset. Other activities included physical training (16%), road marching (15%), confidence/obstacle courses (5%), and barracks activities (3%). Risks per unit of training time were estimated at 13, 62, and 97 injuries per hour for physical training, road marching, and the confidence/obstacle courses, respectively. The most frequently recorded diagnoses were joint pain (27%), strains (15%), blisters (14%), sprains (13%), and tendonitis (12%). The types of injuries and their anatomical locations were similar to those reported in other IET investigations, although blister-related encounters were higher. This investigation identifies activities with the highest risk of injury in IET and those that should be targeted for injury prevention efforts.

Caffeine Use among Active Duty Navy and Marine Corps Personnel

INTRODUCTION The purpose of this investigation was to examine injury incidence, events associated with injury, and injury risk factors during parachuting in an Army airborne infantry unit. METHODS Injury data were obtained by the investigators on the drop zone and confirmed by a physician. Operational data (potential injury risk factors) were obtained from routine reports published by the infantry unit. Weather data were obtained using a Kestrel Model 4500 pocket weather tracker. RESULTS There were a total of 23,031 jumps resulting in 242 injured soldiers for a crude injury incidence of 10.5 per 1000 jumps. Parachute entanglement incidence was 0.5 per 1000 jumps. Where an event associated with the injury could be determined (67% of cases), these included ground impact (75%), static line problems (11%), tree landings (4%), entanglements (4%), and aircraft exits (3%). Univariate analysis showed that higher injury risk was associated with night jumps (versus day jumps), combat loads (versus unloaded jumps), higher wind speeds, higher dry bulb temperatures, higher humidity, C17 Globemaster or C130 Hercules aircrafts (compared to the other aircraft), exits through aircraft side doors (versus tailgates), and entanglements. Multivariate analysis indicated that independent risk factors for injuries included night jumps, combat loads, higher wind speeds, higher dry bulb temperatures, and entanglements. DISCUSSION This investigation provided injury incidence, events associated with injury, and quantitative assessments of injury risk factors and their interactions during military parachuting. An appreciation of these subjects can assist medical and operational planners in further reducing the incidence of injury during airborne operations.

Secular Trends in the Physical Fitness of United States Army Recruits on Entry to Service, 1975–2013

For many years, U.S. Army soldiers performed physical training (PT) in a modified duty uniform and combat boots. The belief that PT in combat boots was associated with injuries lead to the introduction of running shoes for PT in 1982. A historical comparison was conducted examining injuries before and after the change to running shoes in Basic Combat Training (BCT). Searches in literature databases and other sources identified 16 studies with quantitative data on injury incidence during 8-week BCT cycles. Employing studies with similar injury definitions (n = 12), injury incidence was compared in the boot and running shoe periods using meta-analyses, χ(2) statistics, and risk ratios (RRs) with 95% confidence intervals (95% CIs). The boot and shoe periods demonstrated little difference in overall injury incidence (men: RR[boot/shoes] = 1.04, 95% CI = 0.91-1.18, p = 0.50; women: RR = 0.94, 95% CI = 0.85-1.05, p = 0.27) or in lower extremity injury incidence (men: RR[boot/shoes] = 0.91, 95% CI = 0.64-1.30, p = 0.66; women: RR = 1.06, 95% CI = 0.89-1.27, p = 0.51). These analyses provided little support for a reduction in injury risk after the switch from boots to running shoes for PT in BCT. A large randomized, prospective cohort study should be conducted to determine if injury rates are different when PT is conducted in running shoes versus boots.