Emily Schmied

Injury Reduction Effectiveness of Assigning Running Shoes Based on Plantar Shape in Marine Corps Basic Training

Background: Shoe manufacturers market motion control, stability, and cushioned shoes for plantar shapes defined as low, normal, and high, respectively. This assignment procedure is presumed to reduce injuries by compensating for differences in running mechanics. Hypothesis: Assigning running shoes based on plantar shape will not reduce injury risk in Marine Corps basic training. Study Design: Randomized controlled clinical trial; Level of evidence, 1. Methods: After foot examinations, Marine Corps recruits in an experimental group (E: 408 men, 314 women) were provided motion control, stability, or cushioned shoes for plantar shapes indicative of low, medium, or high arches, respectively. A control group (C: 432 men, 257 women) received a stability shoe regardless of plantar shape. Injuries during the 12 weeks of training were determined from outpatient visits obtained from the Defense Medical Surveillance System. Other known injury risk factors (eg, fitness, smoking, prior physical activity) were obtained from a questionnaire, existing databases, or the training units. Results: Cox regression indicated little difference in injury risk between the E and C groups among men (hazard ratio [E/C] = 1.01; 95% confidence interval, 0.82-1.24) or women (hazard ratio [E/C] = 0.88; 95% confidence interval, 0.70-1.10). Conclusion: This prospective study demonstrated that assigning shoes based on the shape of the plantar foot surface had little influence on injuries even after considering other injury risk factors.

Sex differences in cardiovascular and subjective stress reactions: prospective evidence in a realistic military setting

Abstract Evidence points to heightened physiological arousal in response to acute stress exposure as both a prospective indicator and a core characteristic of posttraumatic stress disorder (PTSD). Because females may be at higher risk for PTSD development, it is important to evaluate sex differences in acute stress reactions. This study characterized sex differences in cardiovascular and subjective stress reactions among military survival trainees. One hundred and eighty-five military members (78% males) were studied before, during, and 24 h after stressful mock captivity. Cardiovascular (heart rate [HR], systolic blood pressure [SBP], diastolic blood pressure [DBP]) and dissociative states were measured at all three time points. Psychological impact of mock captivity was assessed during recovery. General linear modeling with repeated measures evaluated sex differences for each cardiovascular endpoint, and causal steps modeling was used to explore interrelationships among sex, cardiovascular reactions and psychological impact of mock captivity. Although females had lower SBP than males at all three time points, the difference was most pronounced at baseline and during stress. Accordingly, females showed greater residual elevation in SBP during recovery. Females had lower DBP at all three time points. In addition, females reported greater psychological impact of mock captivity than males. Exploratory causal steps modeling suggested that stress-induced HR may partially mediate the effect of sex on psychological impact of mock captivity. In conclusion, this study demonstrated sex-specific cardiovascular stress reactions in military personnel, along with greater psychological impact of stress exposure in females. This research may elucidate sex differences in PTSD development.

Sex Differences in Coping Strategies in Military Survival School

A wealth of research has examined psychological responses to trauma among male military service members, but few studies have examined sex differences in response to trauma, such as coping strategies. This study assessed coping strategies used by male and female U.S. service members completing an intensely stressful mock-captivity exercise, compared strategies by sex, and assessed the relationship between coping and posttraumatic stress symptoms (PTSS). Two hundred service members (78% male) completed self-report surveys before and after mock captivity. Surveys assessed demographics, service characteristics, PTSS, and coping strategies used during mock captivity. Participants used seven coping strategies: denial, self-blame, religion, self-distraction, behavioral disengagement, positive reframing, and planning. Women used denial (p≤.05), self-blame (p≤.05), and positive reinterpretation (p≤.05) strategies more frequently than men, and they had higher PTSS levels following the exercise. Structural equation modeling showed that the relationship between sex and PTSS was fully mediated by coping strategies. The results of this study suggest that reducing the use of maladaptive coping strategies may mitigate PTSS among females. Future efforts should target improving coping during highly stressful and traumatic experiences.

Treatment of Mental or Physical Health Problems in a Combat Zone: Comparisons of Postdeployment Mental Health and Early Separation From Service

The primary aim of this study was to evaluate whether being treated for mental health or nonbattle physical injury during military combat deployment was associated with higher risk for postdeployment mental disorders and poorer career outcomes than seen in the general combat-deployed population. Service members treated in theater for mental health (n = 964) or noncombat injury (n = 853) were compared with randomly sampled personnel (n = 7,220) from the general deployed population on diagnosed mental disorders and early separation from service. Deployment, medical, and career information were obtained from Department of Defense archival databases. Over half of the personnel who received mental health treatment while deployed were diagnosed with 1 or more mental disorders postdeployment and/or were separated from service before completing their full-term enlistment. This was significantly higher than expected compared to the general deployed group, adjusting for demographic/military characteristics and mental health history (adjusted odds ratios [ORs] ranging 1.62 to 2.96). Frequencies of problems also were higher in the mental health-treated group than in the group treated for nonbattle physical injuries (significant adjusted ORs ranging 1.65 to 2.58). The documented higher risks for postdeployment adjustment problems suggested that especially those treated in theater by mental health providers might benefit from postdeployment risk-reduction programs.

Physical Aggression Among Post-9/11 Veterans

Understanding risk factors for physical aggression among recently separated combat veterans is important for prevention. We examined longitudinal and concurrent risk factors in the year following military separation. A total of 474 Marines completed questionnaires prior to separation and again in the first year of civilian life. In multivariate analyses, younger age, greater combat exposure, and post-traumatic stress disorder (PTSD) or depression symptoms were associated with increased risk of physical aggression after separation. Problem alcohol use was a significant risk factor concurrently but not longitudinally. This study underscores the need to examine multiple time points and risk factors.