Daniel W. Trone

Gender differences in musculoskeletal injury rates: a function of symptom reporting?

PURPOSE This study determined gender differences in voluntary reporting of lower extremity musculoskeletal injuries among U.S, Marine Corps (USMC) recruits, and it examined the association between these differences and the higher injury rates typically found among women trainees. METHODS Subjects were 176 male and 241 female enlisted USMC recruits who were followed prospectively through 11 wk (men) and 12 wk (women) of boot camp training. Reported injuries were measured by medical record reviews. Unreported injuries were determined by a questionnaire and a medical examination administered at the completion of training. RESULTS Among female recruits the most commonly reported injuries were patellofemoral syndrome (10.0% of subjects), ankle sprain (9.1%), and iliotibial band syndrome (5.8%); the most common unreported injuries were patellofemoral syndrome (2.1%), metatarsalgia (1.7%), and unspecified knee pain (1.7%). Among male recruits iliotibial band syndrome (4.0% of subjects), ankle sprain (2.8%), and Achilles tendinitis/bursitis (2.8%) were the most frequently reported injuries; shin splints (4.6%), iliotibial band syndrome (4.0%), and ankle sprain (2.8%) were the most common unreported diagnoses. Female recruits were more likely to have a reported injury than male recruits (44.0% vs 25.6%, relative risk (RR) = 1.72, 95% confidence interval (CI) 1.29-2.30), but they were less likely to have an unreported injury (11.6% vs 23.9%, RR = 0.49, 95% CI 0.31-0.75). When both reported and unreported injuries were measured, total injury rates were high for both sexes (53.5% women, 45.5% men, RR = 1.18, 95% CI 0.96-1.44), but the difference between the rates was not statistically significant. CONCLUSIONS Our results indicate that the higher injury rates often found in female military trainees may be explained by gender differences in symptom reporting.

Factors associated with discharge during marine corps basic training.

This prospective study assessed risk factors for discharge from basic training (BT) among 2,137 male Marine Corps recruits between February and April 2003. Physical and demographic characteristics, exercise, and previous lower extremity injuries before arrival at Marine Corps Recruit Depot were assessed by questionnaire during intake processing. Stress fractures were confirmed by x-ray, triple-phase bone scan, or magnetic resonance imaging. Overall, 223 (10.4%) participants were discharged from training. In addition to the occurrence of a stress fracture during BT, older age (>23 years), non-Hispanic race, poor incoming self-rated physical fitness, no history of competitive exercise, and an incoming lower extremity injury with incomplete recovery were independent risk factors for discharge. Strategies to identify and allow the proper healing time for pre-BT lower extremity injuries, including interventions to improve the physical fitness of recruits before BT and reduce stress fractures during BT, may be indicated to lower attrition.

Injury-Reduction Effectiveness of Prescribing Running Shoes on the Basis of Foot Arch Height: Summary of Military Investigations

STUDY DESIGN Secondary analysis of 3 randomized controlled trials. Objective Analysis of studies that examined whether prescribing running shoes on the basis of foot arch height influenced injury risk during military basic training. BACKGROUND Prior to 2007, running magazines and running-shoe companies suggested that imprints of the bottom of the feet (plantar shape) could be used as an indication of foot arch height and that this could be used to select individually appropriate types of running shoes. METHODS Similar studies were conducted in US Army (2168 men, 951 women), Air Force (1955 men, 718 women), and Marine Corps (840 men, 571 women) basic training. After foot examinations, recruits were randomized to either an experimental or a control group. Recruits in the experimental group selected or were assigned motion-control, stability, or cushioned shoes to match their plantar shape, which represented a low, medium, or high foot arch, respectively. The control group received a stability shoe regardless of plantar shape. Injuries during basic training were assessed from outpatient medical records. RESULTS Meta-analyses that pooled results of the 3 investigations showed little difference between the experimental and control groups in the injury rate (injuries per 1000 person-days) for either men (summary rate ratio = 0.97; 95% confidence interval [CI]: 0.88, 1.06) or women (summary rate ratio = 0.97; 95% CI: 0.85, 1.08). When injury rates for specific types of running shoes were compared, there were no differences. CONCLUSION Selecting running shoes based on arch height had little influence on injury risk in military basic training. LEVEL OF EVIDENCE Prevention, level 1b.

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

Negative first-term outcomes associated with lower extremity injury during recruit training among female Marine Corps graduates.

39; 31% of service members spent ≥

Caffeine Use among Active Duty Navy and Marine Corps Personnel

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.

Self-Reported Smoking and Musculoskeletal Overuse Injury Among Male and Female U.S. Marine Corps Recruits

This study assessed the impact of lower extremity injuries and stress fractures during recruit training on first-term outcomes among female Marine Corps graduates. Injury data were collected from women recruits at Parris Island, South Carolina (1995-1999) and negative first-term outcomes were obtained from the Career History Archival Medical and Personnel System. The three negative outcomes included (1) failure to complete first-term of service, (2) failure to achieve rank of corporal, and (3) failure to reenlist. Overall, 22% did not complete their first-term enlistment and 12% of those who did were not promoted to corporal. After adjustment for demographic characteristics, not completing first term and not being promoted to corporal were both associated with injuries or stress fracture during training. Reenlistment was not associated with training injuries. Our findings indicate lower extremity injuries among women undergoing Marine Corps recruit training are associated with poor first-term outcomes even among those who graduate.

The Association of Self-Reported Measures With Poor Training Outcomes Among Male and Female U.S. Navy Recruits

Data from the National Health and Nutrition Examination Survey (NHANES) indicate 89% of Americans regularly consume caffeine, but these data do not include military personnel. This cross-sectional study examined caffeine use in Navy and Marine Corps personnel, including prevalence, amount of daily consumption, and factors associated with use. A random sample of Navy and Marine Corps personnel was contacted and asked to complete a detailed questionnaire describing their use of caffeine-containing substances, in addition to their demographic, military, and lifestyle characteristics. A total of 1708 service members (SMs) completed the questionnaire. Overall, 87% reported using caffeinated beverages ≥1 time/week, with caffeine users consuming a mean ± standard error of 226 ± 5 mg/day (242 ± 7 mg/day for men, 183 ± 8 mg/day for women). The most commonly consumed caffeinated beverages (% users) were coffee (65%), colas (54%), teas (40%), and energy drinks (28%). Multivariable logistic regression modeling indicated that characteristics independently associated with caffeine use (≥1 time/week) included older age, white race/ethnicity, higher alcohol consumption, and participating in less resistance training. Prevalence of caffeine use in these SMs was similar to that reported in civilian investigations, but daily consumption (mg/day) was higher.

Epidemiology of Stress Fracture and Lower Extremity Overuse Injury in Female Recruits

The association between self-reported smoking and overuse injury in a cohort of young men (n = 900) and women (n = 597) undergoing 12 weeks of standardized military instruction, after adjustment for physical activity, health history, and incoming fitness tests was examined. The outcome includes all International Classification of Diseases, 9th Revision codes related to injuries resulting from cumulative microtrauma (overuse injuries). The short survey asked about the subjects demographics, smoking habits, prior injuries sustained, physical activity level, self-perceived fitness, and (for women) menstrual history. From the survey, 4 questions established smoking behavior: smoked at least 100 cigarettes in lifetime, age smoked a whole cigarette for the first time, how many cigarettes smoked during the last 30 days, and how many cigarettes smoked per day during the last 30 days. None of the adjusted hazard ratios for the smoking questions were associated with an increased risk of overuse injury for either sex. Furthermore, this study did not find a significant association with respect to smoking and all injuries in either men or women. In conclusion, smoking does not appear to be an independent risk factor for overuse injury in either young men or women during 12 weeks of standardized military instruction.

Running Mileage, Movement Mileage, and Fitness in Male U.S. Navy Recruits

This prospective study evaluated the association of self-reported health habits and behaviors in 2,930 Navy recruits with poor training outcomes, defined as graduating late or separating from training. Although 17% of the men and 21% of the women had a poor training outcome, results suggest that some self-reported measures were associated with poor training outcomes. Men who did not run or jog at least 1 month before basic training or had a previous lower limb injury without complete recovery and women reporting the same or less physical activity compared with their same-age counterparts were more likely to have a poor training outcome. An important first step in decreasing poor training outcomes is encouraging incoming recruits to participate in physical activity and taking steps to identify and rehabilitate recruits who are not completely healed from a lower limb musculoskeletal injury before reporting to basic training.