Marine Corps Basic Training Research Articles

Effects of vitamin D supplementation on salivary immune responses during Marine Corps basic training.

Vitamin D's role in regulating immune responses may increase during periods of elevated psychological and physiological stress. Due to the high demands placed on US Marine Corps recruits undergoing 12weeks of basic military training, we hypothesized that vitamin Dstatus would be related to markers of innate mucosal immunity, and daily vitamin D supplementation would augment immune responses during training. Males (n=75) and females (n=74) entering recruit basic training during the summer and winter volunteered to participate in a randomized, double-blind, placebo-controlled study. Subjects received either 1000IU vitamin D3 +2000mg calcium/d (n=73) or placebo (n=76) for 12weeks. Saliva samples were collected pre-training, during (weeks 4 and 8), and post-training (week 12) in order to determine salivary SIgA and cathelicidin (indices of mucosal immunity) and α-amylase (indicator of stress). Initial (baseline) and post-training serum 25(OH)D levels were measured. Results were as follows: serum 25(OH)D levels were 37% higher in recruits entering training in summer compared with winter. A positive relationship was observed between baseline 25(OH)D levels and SIgA secretion rates (-SR). When stress levels were high during summer training, baseline 25(OH)D levels contributed to an increase in salivary secretory immunoglobulin A secretion rates (SIgA-SR) and cathelicidin-SR, the latter only in males. Vitamin D supplementation contributed to the changes in SIgA-SR and cathelicidin-SR, specifically SIgA-SR was higher in the treatment group. These data highlight the importance of vitamin D and mucosal immune responses during arduous basic military training when stress levels are increased.

Longitudinal Effect of United States Military Policy on Contraception Use and Childbirth Among Junior Enlisted [10OP

INTRODUCTION: Contraceptive use and unintentional pregnancy rates among junior enlisted vary between United States service-branches, despite equal access to no-cost contraception. Therefore, branch-specific policy may influence contraceptive use. METHODS: Secondary analysis of insurance records from 92,072 servicewomen, who attended basic training between 2013 and 2017, assessing the longitudinal effect of changes in branch-specific contraceptive policy on rates of: longer-acting (depot-medroxyprogesterone, implant, and intrauterine) contraception use at six months on active duty; and childbirth during the first 24-months of active duty. Multivariable Logistic (contraception use) and Cox (time to childbirth) Regression models were used to compare outcomes before and after the intervention, between the service making the intervention and the other three branches, and the interaction between these variables. IRB approved. RESULTS: Group contraceptive education emphasizing implantable and intrauterine methods followed by individual contraceptive consultation with a provider for all female, Navy basic trainees increased longer-acting method use (11.8% to 24.3%, Interaction Term OR: 2.14 (95% CI: 1.92-2.39), P<.001) and decreased childbirth rates (7.5% to 6.3%, HR: 0.86 (0.76-0.88), P=.015). Restricting time away from training for implant or intrauterine method insertion during Marine Corps basic training and providing education emphasizing use of depot-medroxyprogesterone for menstrual control decreased overall longer-acting method use (16.2% to 10.0%, OR: 0.43 (0.38-0.49), P<.001) and increased childbirth rates (8.0% to 9.7%, HR: 1.24 (1.02-1.51), P=.027). Allowing contraceptive implant placement during basic training increased use of longer-acting contraception among Air Force recruits 4.4% to 6.9%, OR: 1.31 (1.14-1.51), P<.001). CONCLUSION: Branch-specific changes in military contraceptive policy significantly impact contraceptive use and childbirth rates among junior enlisted.

Creative linguistic impoliteness as aggression in Stanley Kubrick’sFull Metal Jacket

AbstractStanley Kubrick’s anti-war filmFull Metal Jacket(1987) dramatically represents US Marine Corps basic training during the Vietnam War as both gruelling and brutalising. The brutal, linguistically aggressive and physically intimidating scenes purport to detail the dehumanising process that Marine Corps recruits were put through in preparation for combat during that period. In the film, the recruits are trained by Gunnery Sergeant Hartman, played by the actor R. Lee Ermey, who is himself an ex-Marine Corps drill instructor (1965–1967) and who also served in Vietnam in 1968. As a result of his experience as an instructor, Ermey was given free rein by Kubrick to write his own dialogue for the abusive barrack room and field training scenes in order to lend the drama an air of authenticity (see Ermey 2017). Within the fictional world of the film, the intense training and disciplinary regime ultimately causes one recruit, Private Leonard Lawrence, to crack psychologically. Private Lawrence is nicknamed ‘Gomer Pyle’ by Hartman upon their first meeting, this name being a direct allusion to the hapless character of the same name who was a US Marine recruit in the sitcomGomer Pyle, U.S.M.C., which ran from 1964–1969 – contemporaneously with the time period in whichFull Metal Jacketis set. This insulting allusion is merely the start of a long line of linguistically impolite/aggressive and ultimately physically aggressive interactions which Lawrence/Pyle suffers at the hands of Hartman, both directly and, later in the film as a result of Hartman’s orchestrations, from the other recruits. Under this unrelenting barrage of impoliteness, aggression, and abuse, Lawrence/Pyle eventually shoots Hartman dead before turning his rifle on himself and committing suicide. Thus, the film argues that the dehumanising effect of the basic training, which was ostensibly carried out to toughen up and mentally prepare conscripted recruits for combat in Vietnam, had a profound, brutalising and (potentially) utterly destructive effect on those subjected to it. In this article, we explore the creative linguistic aggression displayed by the character of Hartman. We focus particularly on the reasons underlying the creativity of Hartman’s impoliteness and aggression, and argue that these are essentially to foreground the seriousness of the training regime which the recruits must follow.

Injuries and Footwear (Part 1): Athletic Shoe History and Injuries in Relation to Foot Arch Height and Training in Boots.

This article traces the history of the athletic shoe, examines whether selecting running shoes based on foot arch height influences injuries, and examines historical data on injury rates when physical training (PT) is performed in boots versus running shoes. In the 1980s and into the 2000s, running shoe companies were advertising specialized shoes with "motion control," "stability," and "cushioning," designed for individuals with low, normal, and high arches, respectively. Despite marketing claims that these shoes would reduce injury rates, coordinated studies in Army, Air Force, and Marine Corps basic training showed that assigning or selecting shoes on this basis had no effect on injury rates. Consistent with this finding, biomechanical studies have shown that the relationships between arch height, foot joint mobility, and rear-foot motion are complex, variable, and frequently not as strong as often assumed. In 1982, the US Army switched from PT in boots to PT in running shoes because of the belief that boots were causing injuries and that running shoes would reduce injury rates. However, a historical comparison of injury rates before and after the switch to running shoes showed virtually no difference in injury risk between the two periods. It is not clear at this point if the type of footwear effects injury incidence.

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.

Psychosocial Predictors of Return to Duty Among Marine Recruits With Musculoskeletal Injuries

Psychosocial factors may have an important impact on injury recovery and return to work. To explore the influence of psychosocial factors in a cohort of injured military personnel, data were collected from 166 Marine Corps basic training recruits with musculoskeletal injuries. This sample was followed prospectively to determine whether they graduated from basic training or were discharged from the Marines. Demographic, injury-related, and psychosocial factors were analyzed to determine predictors of failure to graduate from basic training. The strongest risk factors for failing to graduate were not expecting to graduate, low or uncertain career intentions, lack of determination, psychological distress, and low organizational commitment. In the final multivariate logistics model, two predictors of failure to graduate emerged: not expecting to graduate and low or uncertain career intentions. The results suggest that interventions to reduce attrition in injured military populations should be designed to counter pessimistic expectations and emphasize career opportunities.

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.

Predictors of Stress Fracture Susceptibility in Young Female Recruits

Background Stress fractures account for substantial morbidity for young women undergoing U.S. Marine Corps basic training. Hypothesis Certain pretraining characteristics identify women at increased risk of stress fractures during boot camp. Study Design Cohort study; Level of evidence, 2. Methods Data collected included baseline performance on a timed run (a measure of aerobic fitness), anthropometric measurements, and a baseline questionnaire highlighting exercise and menstrual status among 2962 women undergoing basic training at the Marine Corps Recruit Depot, Parris Island, in 1995 and 1996. Results One hundred fifty-two recruits (5.1%) had 181 confirmed lower extremity stress fractures, with the most common sites being the tibia (25%), metatarsals (22%), pelvis (22%), and femur (20%). Logistic regression models revealed that having low aerobic fitness (a slower time on the timed run) and no menses during the past year were significantly associated with the occurrence of any stress fracture and with pelvic or femoral stress fracture during boot camp. Conclusion These findings suggest that stress fractures may be reduced if women entering Marine Corps Recruit Depot training participated in pretraining activities designed to improve aerobic fitness. Furthermore, women reporting no menses during the previous year may need additional observation during training. Clinical Relevance Consistent with previous studies, we found that low aerobic fitness was the only modifiable risk factor associated with stress fractures during boot camp.

Pretraining And Menstrual Factors Associated With Stress Fracture In Recruits

Stress fractures account for substantial morbidity, especially for young women undergoing U.S. Marine Corps basic training. PURPOSE To examine pretraining characteristics that may identify women at increased risk of stress fractures during boot camp. METHODS We prospectively followed 813 women undergoing basic training at the Marine Corps Recruit Depot (MCRD), Parris Island, in 1999. Data collected included performance on a timed run, anthropomorphic measurements, and a baseline questionnaire highlighting exercise and health habits. The women were followed throughout the 13 weeks of boot camp for occurrence of stress fractures. Stress fracture was confirmed by clinical diagnosis, positive radiograph, and/or bone scan. RESULTS Fifty-six (6.9%) had 66 confirmed lower extremity stress fractures, with the most common sites being the tibia (57.6%), pelvis (13.6%), and femur (12.1%). Logistic regression models revealed that low physical fitness (a slower time on the initial run test)(OR=3.32; 95% CI, 1.4–8.1), secondary amenorrhea (6 or more consecutive months without menses during the past year) (OR=3.83; 95% CI, 1.4–10.3], and delayed age of menarche (13 years or older) (OR=2.13; 95% CI, 1.1–4.0) were significantly associated with the occurrence of stress fractures during boot camp. Recruits who participated in lower body weight training 2 or more times/weekly consistently for 7 or months/year were less likely to incur a stress fracture (1.5%) than recruits who performed lower body weight training 0–6 months/year (7.9%; p<0.036). CONCLUSIONS Consistent with previous studies, we found that low aerobic fitness is a modifiable risk factor to reduce training-related stress fracture. In addition, we also found lower body weight training to be another modifiable factor to decrease stress fracture during training. These findings suggest that stress fractures may be minimized if women entering MCRD training actively participate in pretraining activities designed to improve aerobic fitness and increase lower body strength. Furthermore, women reporting secondary amenorrhea during the previous year or delayed menarche may need additional observation during training. This work was supported by the Naval Health Research Center under Work Unit No. 60213.

Running Shoe Type and Attrition During Marine Corps Basic Training

PURPOSE To determine if an improved type of running shoe was associated with attrition during US Marine Corps recruit training. METHODS This prospective study consisted of 2,142 male recruits who entered the Marine Corps Recruit Depot (MRCD), San Diego, CA between February and April 2003 and agreed to complete a health and fitness survey. Thirty-six percent of the recruits were assigned the test shoe and 64% were assigned the traditional running shoe by equipment issue personnel not involved with the study. Recruits were followed until graduation (at least 12 weeks) or separation. Three outcome measures were assessed; on-time graduation, delayed graduation, or separated prior to graduation. RESULTS The average age of the 2,142 recruits was 20 years and did not vary by shoe type. Further, no differences for shoe type on height, weight, BMI, shoe size, self-reported running pace, or race/ethnicity were found between the recruits in the two running shoe groups. The recruits were predominantly white (66%) and Hispanic (21%). Overall, 89.4% of the recruits finished the 12-week training and graduated (89.5% for the test shoe and 89.3% for the standard shoe), 82% of the recruits graduated on time (82.2% and 81.9%), and 10.6% separated prior to graduation (10.5% and 10.7%). Assigned shoe type was not associated with any of the attrition parameters measured. CONCLUSIONS The type of running shoe issued did not appear to affect graduation status, however, further analyses need to assess the relationship between injury status between the recruits who wore the test or traditional shoe. This work was supported by Naval Health Research Center under Work Unit No. 60213.

Running Shoe Type and Attrition During Marine Corps Basic Training

PURPOSE To determine if an improved type of running shoe was associated with attrition during US Marine Corps recruit training. METHODS This prospective study consisted of 2,142 male recruits who entered the Marine Corps Recruit Depot (MRCD), San Diego, CA between February and April 2003 and agreed to complete a health and fitness survey. Thirty-six percent of the recruits were assigned the test shoe and 64% were assigned the traditional running shoe by equipment issue personnel not involved with the study. Recruits were followed until graduation (at least 12 weeks) or separation. Three outcome measures were assessed; on-time graduation, delayed graduation, or separated prior to graduation. RESULTS The average age of the 2,142 recruits was 20 years and did not vary by shoe type. Further, no differences for shoe type on height, weight, BMI, shoe size, self-reported running pace, or race/ethnicity were found between the recruits in the two running shoe groups. The recruits were predominantly white (66%) and Hispanic (21%). Overall, 89.4% of the recruits finished the 12-week training and graduated (89.5% for the test shoe and 89.3% for the standard shoe), 82% of the recruits graduated on time (82.2% and 81.9%), and 10.6% separated prior to graduation (10.5% and 10.7%). Assigned shoe type was not associated with any of the attrition parameters measured. CONCLUSIONS The type of running shoe issued did not appear to affect graduation status, however, further analyses need to assess the relationship between injury status between the recruits who wore the test or traditional shoe. This work was supported by Naval Health Research Center under Work Unit No. 60213.

Acute Intracranial Boxing-Related Injuries in U.S. Marine Corps Recruits: Report of Two Cases

Serious acute intracranial injuries from boxing are a recognized, albeit rare, event. Acute brain injuries such as concussion, hemorrhage, and contusion are easily recognized because of their rapid onset of neurological impairment. The sequelae of such injuries range from transient diminished cognitive function to irreversible brain damage and, on occasion, death. The more serious injuries are certainly minimized as a result of regulatory policy, improved medical awareness, and the use of safety equipment. The incidence of serious acute head injury in amateur boxing and noncompetitive boxing is lower than that found in the professional ranks. Our survey of instructional boxing in U.S. Marine Corps basic training during an 8-year period detected only three serious acute brain injuries incurred by approximately 180,000 participants, equating to one serious head injury per 60,000 participants. Serious head injuries constituted an extremely small percentage (0.3%) of the approximately 1,100 total boxing-related injuries surveyed during the period. We present two cases of serious acute brain injury incurred during noncompetitive boxing skills instruction as a part of U.S. Marine Corps basic training. A review of the data leads us to conclude that the risk of serious head injury in a well-supervised, instructional boxing program is relatively minimal. In any case, we recommend that any boxing be appropriately supervised and that specialized trauma care and an adequate transport mechanism to secure that care be readily available.

Changes in Attitudes and Characteristics of Marine Recruits during the 1960S

Comparative analyses were computed upon 14 attitude items and 8 biographical characteristics of 3 samples of recruits who had entered Marine Corps basic training in 1961, 1967, and 1969. Results indicated that of the 3 samples, the 1961 sample had the most favorable attitudes toward aspects of the Marine Corps, whereas the recruits from the 1967 sample had the least favorable attitudes. The average recruit from the 1961 sample was characterized as being younger, less well educated, and more likely to be unmarried than the average recruit from either the 1967 or 1969 sample. In comparing the samples from 1967 and 1969, the average recruit from 1967 was more intelligent, had attained a higher level of education, and was more likely to be unmarried than the average recruit from 1969. For each of the three samples, scores on the General Classification Test were significantly related to 4 of the 14 attitude items and level of education attained was related to one item. Seven of the attitude items became significantly more favorable during training for the 1969 sample, whereas three of the items became significantly more favorable for the 1967 sample. The results suggested that the training program should provide an opportunity for recruits, and especially the better educated, more intelligent recruit, to experience a greater sense of well-being and personal commitment toward the military.