Weeks Of Basic Military Training Research Articles

Impact of 12 weeks of basic military training on testosterone and cortisol responses

IntroductionMilitary personnel train and operate in challenging multistressor environments, which can affect hormonal levels, and subsequently compromise performance and recovery. The aims of this project were to evaluate concentrations of...

The Effects of Exercise During a 10-Week Basic Military Training Program on the Physical Fitness and the Body Composition of the Greek Naval Cadets.

The period of basic military training (BMT) is a sudden change in the individual habits of the trainees and is characterized by significant improvements in body composition such as the percentage of body fat (%BF) and lean body mass (BM). Research has shown that physical activity during the period of BMT lasting 7-10 weeks has positive effects on the physical condition and BM of cadets. The purpose of this study was to examine the effects of training combining cardiovascular conditioning, circuit strength training, swimming, team sports, and obstacle course on physical fitness and body composition during a 10-week BMT period over 4 years in the Hellenic Naval Academy (HNA). The sample consisted of 185 Greek cadets of the HNA (age: 18.4 ± 0.7 years, height: 1.77 ± 6.7 m, BM: 72.6 ± 9.1 kg), of which 153 was male (age: 18.3 ± 0.6 years, height: 1.79 ± 5.8 cm, BM: 75.3 ± 7.6 kg) and 32 was female (age: 18.6 ± 0.9 years, height: 1.68 ± 2.8 cm, BM: 59.9 ± 3.1 kg).The cadets participated each year for 4years in the BMT, performing 94 training sessions, five times a week. The weekly training program included cardiovascular conditioning, circuit strength training, swimming, team sports, and obstacle course. The measurements of the participants before and after BMT were on BM, %BF, and body mass index (BMI); on the number of sit-ups (SU1), push-ups (PU1), and pull-ups (PullU1) in 1minute; and on the 12-minute aerobic Cooper test (12-min run). The results of the study showed that the BM of the cadets decreased significantly by 2.5%, (t184 = 17.591, P<.01), in men by 2.7% (t152 = 16.243, P<.01) and in women by 2.2% (t31 = 9.280, P<.01). Body mass index (BMI) decreased significantly by 2.6% (t184 = 17.681, P<.01), in men by 3.0% (t152 = 16.046, P<.01) and in women by 2.3% (t31 = 9.224, P<0.01). Reduction in %BF in all cadets reached 11.3% (t184 = 8.134, P<.01), for men -14.8% (t152 = 8.918, P < .01) and women -2.1% (t31 = 0.860, P>.05) without significant differences between the measurements.The number of push-ups in 1minute (PU1) significantly increased by 27.6% (t184 = -27.813, P<.01), in women by +35.6% (t31 = 13,864, P<.01). The number of sit-ups in 1minute (SU1) significantly increased by 27.3% (t184 = -30.501, P<.01), for men +28.8% (t152 = -29.862, P<.01). The number of pull-ups in 1minute (PullU1) reached 20.8% (t184 = -13.426, P<.01) in total, at similar levels in men (t152 = -13.918, p<.01) and women (t31 = -2.820, P<.01).On the 12-min run, the significant improvement exceeded 10.8% (t184 = -45.289, P<.01), in men by 11.1% (t152=-45.222, P<.01) while in women by 9.0% (t31 = 15.709, P<.01). The results of this study showed that 10 weeks of BMT, which combined cardiovascular conditioning, circuit strength training, swimming, team sports, and obstacle course improved the body composition, cardiorespiratory endurance, and the strength of the Greek HNA cadets.

Associations between inflammatory markers and well-being during 12weeks of basic military training.

Stress, anxiety and physical exertion are all closely linked to well-being, and each can alter immune function. Diminished well-being has been observed during military training, however there is mixed evidence regarding whether concomitant changes in inflammatory markers occur, with these phenomena indicating potential maladaptive responses to imposed training loads. The aims of this project were (1) assess changes in inflammation and subjective well-being across a 12-week basic military training (BMT) program, and (2) evaluate relationships between circulating inflammatory markers and well-being. A total of 37 men and women undergoing 12weeks of BMT in Australia were recruited. Well-being was assessed via questionnaire (DASS-21), and plasma samples were collected for the analysis of inflammatory cytokines [interleukin (IL)-4, IL-6, IL-1β, IL-8, IL-10, and tumor necrosis factor (TNF)-α] at weeks 1, 4, 8 and 12. Data were analysed using general linear mixed models. Depression, anxiety and stress subscale scores all significantly improved (all P ≤ 0.001), and TNF-α decreased (P = 0.031) across time. Compared to baseline (week 1), significant decreases in associations between depression and IL-10, anxiety and IL-10, and stress and IL-10, IL-4 IL-6 and TNF-α (all P < 0.05), were detected across BMT. The BMT program appears to support improved well-being over the 12weeks, with minimal perturbation to inflammatory markers. Biomarkers and well-being displayed consistent associations and may have utility as psychophysiological indicators of health status in military research, however for now, subjective measures may represent more cost-effective proxies for ongoing monitoring of military personnel.

Distance travelled by military recruits during basic training is a significant risk factor for lower limb overuse injury

IntroductionMilitary initial training results in a high incidence of lower limb overuse injuries (stress fractures and medial tibial stress syndrome). This study aimed to determine whether the distance travelled by...

The Effect of Five Weeks of Basic Military Training on Physical Fitness and Blood Biochemical Factors in Obese Military Recruits Just Conscripted into the Army

PURPOSE: The purpose of this study was to investigate the effects of 5 weeks of basic military training on the physical fitness and blood biochemical factors in obese military recruits.METHODS: Forty-eight male recruits (20-25 years of age) were randomly assigned to the Control group and Exercise group. Both groups completed 5 weeks of basic military training. The Exercise group additionally performed a resistance exercise twice daily in the morning and afternoon (1-3 sets, 3 days per week) and power walking (60-80% HRmax, 30 minutes) four times weekly. Four body composition variables, physical fitness factors, serum lipid profiles, and obesity-related hormone levels were analyzed.RESULTS: Body weight, body fat ratio, body mass index, and waist circumference were significantly decreased in both groups between pre- and post-exercise tests (&lt;i&gt;p&lt;/i&gt;&lt;.01). However, no changes in these parameters were observed between the Control and Exercise groups. Twenty-meter shuttle running and maximal oxygen uptake were significantly increased post exercise (&lt;i&gt;p&lt;/i&gt;&lt;.001). Total cholesterol, triglyceride, and low-density lipoprotein levels were significantly decreased in both (Control and Exercise) post-exercise tests (&lt;i&gt;p&lt;/i&gt;&lt;.05). Leptin in both groups was significantly decreased; however, ghrelin showed a reverse pattern (&lt;i&gt;p&lt;/i&gt;&lt;.01). A significantly changed maximal oxygen uptake value via training was noted in both groups (&lt;i&gt;p&lt;/i&gt;&lt;.001). The time and interaction between the groups and the time were also significantly affected (&lt;i&gt;p&lt;/i&gt;&lt;.001).CONCLUSIONS: Our findings suggest that an additional exercise-training program with the basic military training plays an important role in improving military fitness and combat power.

The Effect of Five Weeks of Basic Military Training on Physical Fitness and Blood Biochemical Factors in Obese Military Recruits Just Conscripted into the Army

PURPOSE: The purpose of this study was to investigate the effects of 5 weeks of basic military training on the physical fitness and blood biochemical factors in obese military recruits.METHODS: Forty-eight male recruits (20-25 years of age) were randomly assigned to the Control group and Exercise group. Both groups completed 5 weeks of basic military training. The Exercise group additionally performed a resistance exercise twice daily in the morning and afternoon (1-3 sets, 3 days per week) and power walking (60-80% HRmax, 30 minutes) four times weekly. Four body composition variables, physical fitness factors, serum lipid profiles, and obesity-related hormone levels were analyzed.RESULTS: Body weight, body fat ratio, body mass index, and waist circumference were significantly decreased in both groups between pre- and post-exercise tests (&lt;i&gt;p&lt;/i&gt;&lt;.01). However, no changes in these parameters were observed between the Control and Exercise groups. Twenty-meter shuttle running and maximal oxygen uptake were significantly increased post exercise (&lt;i&gt;p&lt;/i&gt;&lt;.001). Total cholesterol, triglyceride, and low-density lipoprotein levels were significantly decreased in both (Control and Exercise) post-exercise tests (&lt;i&gt;p&lt;/i&gt;&lt;.05). Leptin in both groups was significantly decreased; however, ghrelin showed a reverse pattern (&lt;i&gt;p&lt;/i&gt;&lt;.01). A significantly changed maximal oxygen uptake value via training was noted in both groups (&lt;i&gt;p&lt;/i&gt;&lt;.001). The time and interaction between the groups and the time were also significantly affected (&lt;i&gt;p&lt;/i&gt;&lt;.001).CONCLUSIONS: Our findings suggest that an additional exercise-training program with the basic military training plays an important role in improving military fitness and combat power.

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.

SAT-218 Hypothalamic-Pituitary-Gonadal (HPG) and Hypothalamic-Pituitary-Adrenal (HPA) Axis Responsiveness in Women and Men during 29 Weeks of Basic Military Training

Exercise-associated endocrinopathy in athletes has been attributed to low energy availability (EA). We hypothesized this would be relevant to British Army Officer training, which involves arduous exercise and non-exercise stressors. We aimed to explore changes in LH, FSH and cortisol responsiveness in women and in a smaller cohort of men over 29 weeks of basic military training. We studied fifty-six Officer Cadets (age 24.4 ± 2.5 years, 47 female: combined contraceptive pill users (CCP, n=14), progestogen-only users (PROG, n=16), and non-contraceptive and intrauterine device users (NONE, n=17)) on entering (week (w)1) and completing (w29) training. Body composition was measured by DXA and average monthly hair cortisol by LC-MS. A combined low dose 10µg GnRH and 1.0µg ACTH-(1-24) test was performed with LH, FSH and cortisol measured by LC-MS at baseline, 20, 30 and 60 mins. For cortisol analyses, PROG and NONE groups were considered seperately (as PROG/NONE), due to CCP increasing CBG. Weight increased in both women and men over the training period (mean ±SD, 64.4 ±7.4 kg vs 65.3 ±7.2 kg, p=0.05 and 84.5 ±7.4 kg vs 87.0 ±9.1 kg, p=0.02, respectively), comprising increased fat but not lean mass. Menstrual cyclicity in NONE was unchanged. Training blunted the peak LH- and FSH-foldwise response to GnRH in women (median [IQR] 5.74 [3.23, 19.7] vs 3.44 [2.62, 6.51], p=0.002 and 1.65 [1.37, 2.37] vs 1.39 [1.25, 1.77], p=0.005, respectively) but not men (4.28 [2.92, 4.73] vs 3.29 [2.34, 5.78], p=0.5 and 1.46 [1.30, 1.56] vs 1.34 [1.21, 1.51], p=0.6, respectively). Hair cortisol was higher in women than men over the 3 months before training (median (IQR) 7.71 (3.85, 16.0) pg/mg vs 3.53 (2.95, 5.89) pg/mg, p<0.0001) and remained higher in women in the final 3 months of training (8.18 (3.61, 10.37) vs 3.38 (2.38, 5.79) pg/mg, p=0.001). Basal cortisol tended to be lower among PROG/NONE than males in w1 (177 ± 91.9 vs 313 ±92.9 nmol/l, p=0.08), but increased by w29 in PROG/NONE but not men (to 259 ±103 nmol/l; p=0.003 vs to 246 ±187 nmol/l; p=0.4, respectively). Cortisol response to ACTH was blunted in PROG/NONE (peak foldwise increase 3.83 ±1.5 vs 2.84 ±1.0, p=0.048) but was unchanged in men (2.96 ±0.9 vs 2.46 ±0.9, p=0.3). No significant cortisol changes were seen in CCP.The elevated hair cortisol in women may represent greater anticipatory response than men. Hair and basal plasma cortisol increased in women compared to men in response to training, though LH, FSH and cortisol responsiveness in women was blunted. While our findings are broadly in accord with previous reports of exercise and training-associated pituitary and adrenal suppression, our novel finding is that this was not associated with evidence of low EA in our population. We propose endocrine changes in arduous training reflect complex interactions of sex and stressors with the HPA and HPG axes.

The association between risky health behaviours and socio-economic status in Canadian Armed Forces recruits: the mediating effect of health-risk attitudes

Introduction: Socio-economic status (SES) is significantly associated with health outcomes and behaviours. Low SES in childhood has been found to predict poor health outcomes in young adulthood. Furthermore, low SES has been linked to poor health-risk attitudes. It is important to understand the correlates of risky health behaviours and the nature of the relationships among risky health behaviours, SES, and attitudes favouring risky health behaviours. Methods: The Recruit Health Questionnaire (RHQ) was developed to determine demographic information and health behaviours of Canadian Armed Forces (CAF) recruits and is collected during the early weeks of basic military training. We examined the relationship between SES (as measured by previous year’s household income) and risky health behaviours (e.g., smoking, risky drinking), and explored the mediating effect of attitudes favouring health risks (e.g., likelihood of drinking heavily at a social function). We analyzed data from 3,465 CAF recruits (83% male; 76% non-commissioned member recruits; 43% between the ages of 20 and 24 years; 63% having completed at least some post-secondary studies) who completed the RHQ between 2013 and 2014. Results: Low SES was associated with smoking, and high SES with binge drinking and driving under the influence, but, when controlling for age, sex, rank, and education level, there was a significant indirect effect of SES on all risky health behaviours through health-risk attitudes. This suggests that SES prior to military enlistment may affect health behaviours, but health-risk attitudes play a significant role in contributing to risky behaviours. Discussion: It is important to understand the role of SES background on recruits and its role in determining attitudes toward health and risky health behaviours in order to influence policies and targeted health promotion programming to reduce risky health behaviours. Knowing that health-risk attitudes play a significant role in risky health behaviours can influence programming to promote attitudes that are more averse toward health and safety risks.

Influence of gender and peer tobacco use on tobacco use intentions after a period of involuntary tobacco abstinence among U.S. Air Force trainees.

This study examined gender, prior tobacco use, and social-environmental factors as predictors of intentions to use tobacco (cigarette smoking and/or smokeless tobacco [ST]) after a forced period of abstinence among U.S. Air Force (USAF) trainees. Trainees completed 8½ weeks of basic military training (BMT), then 4 weeks of Technical Training; both required abstinence from tobacco. A cross-sectional survey of 13,514 USAF trainees (73% male, 90% age 18–24, 43% prior tobacco use) was conducted at the beginning of the 4-week Technical Training period. Overall, 17% of the sample reported future tobacco use intentions. Intentions for future tobacco use were less prevalent among non-tobacco users before BMT (1%) than those reporting any tobacco use (37%). From a multivariable logistic regression model predicting intentions to use any tobacco after Technical Training, significant two-way interaction effects were detected between gender, and tobacco use prior to BMT (p = 0.0001), and number of close friends who smoked cigarettes (p = 0.018), and number of close friends who used ST (p = 0.029). Among non-tobacco users before BMT, females were more than twice as likely as males to report tobacco intentions (Odds Ratio = 2.2, Bonferroni corrected 95% CI: 1.14.4, p = 0.011); no gender differences were detected among tobacco users. For females, but not males, having more friends who smoked was associated with greater likelihood of tobacco intentions (Bonferroni corrected p ≤ 0.05). In contrast, for males, but not females, having more friends using ST was associated with greater likelihood of tobacco intentions (Bonferroni corrected p < 0.05). In this sample of USAF trainees, the study provides novel findings on how males and females are influenced differently by their prior tobacco use and peers' tobacco use in predicting tobacco intentions. Prevention efforts focused on uptake and resumption of tobacco use, along with gender-specific strategies, may be warranted.

Changes in iron status of British Army recruits in basic military training

Introduction: Iron status has been shown to deteriorate in female soldiers during military training in the US. The aim of this programme was to examine the sub clinical and clinical iron status of British Army recruits at the start (T1) and end (T2) of 14 weeks of basic military training.

Physical fitness level affects perception of chronic stress in military trainees.

This study investigated whether physical fitness affects the perception of chronic stress in military trainees while controlling for established factors influencing stress perception. The sample consisted of 273 men (20.23±1.12years, 73.56±10.52kg, 1.78±0.06m). Physical fitness was measured by progressive endurance run (maximum oxygen uptake; VO2 max), standing long jump, seated shot put, trunk muscle strength, and one leg standing test. Perceived stress was measured using the Perceived Stress Questionnaire in Weeks 1 and 11 of basic military training (BMT). VO2 max and four influencing variables (perceived stress in Week 1, neuroticism, transformational leadership style, and education level) explained 44.44% of the variance of the increase in perceived stress during 10weeks of BMT (R2 =0.444, F=23.334, p<.001). The explained variance of VO2 max was 4.14% (R2 =0.041), with a Cohen's f2 effect size of 0.045 (assigned as a small effect by Cohen, ). The results indicate a moderating influence of good aerobic fitness on the varied level of perceived stress. We conclude that it is advisable to provide conscripts with a specific endurance training program prior to BMT for stress prevention reasons.

Flexibility as risk factor for stress-fracture development in South African male soldiers

Background: Stress fractures are a common military training injury. Flexibility of muscles and joints may directly influence stress-fracture risk by way of altering the forces applied to bone. Hip external rotation and ankle plantar- and dorsiflexion have been inconsistently reported to pose a risk to stress fracture development in military soldiers. Thus this study aimed to present results that could help define the risk flexibility may pose in the development of stress fractures amongst military male soldiers.Methods: An experimental one-group pretest–posttest study design assessing the injury incidence, bilateral hip external rotation, ankle plantar- and dorsiflexion of South African male military soldiers ( n = 100) undergoing 12 weeks of basic military training (BMT) was undertaken. The parametric t -test for dependent samples ( α = 0.05) and effect size (ES) was used to analyse the data.Results: No stress fractures were diagnosed in the 100 operational military training injuries reported. BMT resulted in significant mean decreases of 10% (L) and 17% (R) in hip external rotation and 18% (L) and 14% (R) in ankle plantar flexion respectively, whilst a significant increase of 37% (L) and 39% (R) dorsiflexion was observed.Conclusions: Although normal ankle and limited hip external flexibility do not appear to predispose these male soldiers to stress fracture development these variables should not be excluded as possible intrinsic risk factors.

Flexibility as risk factor for stress-fracture development in South African male soldiers

Background: Stress fractures are a common military training injury. Flexibility of muscles and joints may directly influence stress-fracture risk by way of altering the forces applied to bone. Hip external rotation and ankle plantar- and dorsiflexion have been inconsistently reported to pose a risk to stress fracture development in military soldiers. Thus this study aimed to present results that could help define the risk flexibility may pose in the development of stress fractures amongst military male soldiers.Methods: An experimental one-group pretest–posttest study design assessing the injury incidence, bilateral hip external rotation, ankle plantar- and dorsiflexion of South African male military soldiers (n = 100) undergoing 12 weeks of basic military training (BMT) was undertaken. The parametric t-test for dependent samples (α = 0.05) and effect size (ES) was used to analyse the data.Results: No stress fractures were diagnosed in the 100 operational military training injuries reported. BMT resulted ...

Adapted marching distances and physical training decrease recruits' injuries and attrition.

There is evidence that progressive loading of physical demands at the beginning of basic military service and specific physical training can reduce injury incidences. Therefore, aim of this study was to measure the effects of a progressive increase in marching distances and an adapted physical training program on injury incidence and attrition rate in a Swiss Army infantry training school. One company reduced the distances covered on foot during the first 4 weeks of basic military training. A second company performed an adapted physical training program for 10 weeks. A third company participated in both interventions combined, and a fourth company served as a control group without any intervention. The injury incidences and attrition rates of 651 male recruits were registered during 21 weeks of military service. Several predictor variables for injury and attrition, such as physical fitness, previous injuries, level of previous physical activity, smoking, motivation, and socioeconomic factors, were assessed as well. The data were analyzed using binary logistic backward regressions. Each intervention separately had a favorable effect on injury prevention. However, combining the 2 interventions resulted in the greatest reduction in injury incidence rate (-33%). Furthermore, the adapted physical training successfully reduced the military service attrition rates (-53%).

’n Vergelyking tussen die kardiostres-indekse van ’n aktiewe en ’n sedentêre populasie

Our modern lifestyle often results in the importance of physical exercise being overlooked. The increasingly passive way of life has resulted in a notable increase in the prevalence of lifestyle disorders, such as hypertension and some forms of vascular pathology. This study compares the cardio-stress indices (CSIs) of active and sedentary individuals to provide insight into the impact of the significant changes that have taken place in the modernised society. The active population consisted of 217 military recruits who had completed 20 weeks of basic military training. The sedentary population (n = 126) was sourced from a traditional tertiary institution where the focus is on attending lectures. Participants from both populations were required to attend three testing sessions, which were held during Week 1, Week 12 and Week 20. Subjects underwent a non-invasive ViportTM test to measure their CSI, heart rate and QRS duration. The results showed that although baseline readings for CSI, blood pressure (BP) and heart rate (HR) were initially higher among the active population, the commencement of the physical training programme resulted in a steady decline in respect of these three factors to approach healthier margins. However, the CSI for neither population reached the normal range, indicating that although physical activity reduces physiological stress levels, other key factors, namely lifestyle stress levels, must also be taken into account. The study supports the notion that increased physical activity has the potential to reduce the predisposition of an individual to cardiovascular disorders and contributes towards establishing the effect of training on heart health by using CSI as a means of measurement.

Effects of a 7-Week Outdoor Circuit Training Program on Swiss Army Recruits

The purpose of this study was to implement an outdoor circuit training program as an addition to standard training and to examine its effects on physical fitness and injury incidence rate in Swiss Army recruits. An intervention group (standard and additional training, n = 134, 21.0 ± 1.1 years, 74.1 ± 10.0 kg, and 1.78 ± 0.1 m) and a control group (standard training only, n = 125, 20.4 ± 1.2 years, 73.3 ± 9.1 kg, and 1.78 ± 0.1 m) from the same fusilier infantry training school were compared. Physical standard training in the Swiss Army is specified to consist of 2 sessions with a total duration of at least 3 h·wk(-1). Groups of 20-50 recruits undergo these trainings in a gymnasium hall and outdoors. Standard training includes a wide range of exercises and sport activities (strength and aerobic fitness training, team sports, obstacle courses, physical fitness tests, and orienteering). The additional circuit fitness training program implemented in this study was conducted once a week for 60 minutes. It was performed outdoors and consisted of the same exercises every week (warm-up, squats, prone bridge, back and shoulder exercise, stair climbing, side bridge, single leg balance, walking on a balance beam, intermitted running, and active recovery). Volunteers' physical fitness was assessed during the first and last weeks of basic military training (7 weeks) using a standing long jump, seated 2-kg shot put, 1-leg standing test (OLS), trunk muscle strength test (TMS), and progressive endurance run (PER). Injury data were collected in medical records for the 21 weeks of military training school. The intervention group performed 1.0 session of standard training for 70.0 minutes and 1.0 session of additional outdoor circuit training for 50.0 min·wk(-1). The control group performed 1.3 sessions of standard training for a total of 70.7 min·wk(-1). After the 7-week basic military training, the intervention and the control groups showed significant improvements in OLS (35.63 and 9.79%), TMS (29.84 and 11.31%), PER (15.64 and 16.37%), and total physical fitness score (12.04 and 7.78%, p < 0.05). The intervention group showed significantly greater improvements in OLS, TMS, and total physical fitness score than did the control group (p < 0.05). No significant difference in injury incidence rate between the 2 study groups (intervention group: 14.2, control group: 13.9 injuries per month per 100 persons) was registered. The results indicate that the change from a civilian daily routine to the physically more demanding military routine led to significant improvements in physical fitness in both study groups. The additional outdoor circuit training session per week led to greater improvements in total physical fitness score but did not increase injury rates.

Cardiac autonomic function reveals adaptation to military training

The last 4 weeks of basic military training are very stressful. We tested the hypothesis that changes in cardiac autonomic function during this period are associated with changes in maximal oxygen uptake and/or serum hormonal concentrations in male conscripts (n=22). Cardiac vagal autonomic function was assessed by measuring the high-frequency (0.15–0.4 Hz) spectral power of R–R intervals. Maximal oxygen uptake ([Vdot]O2max) and basal serum testosterone concentration were measured at the beginning and end of the period. Individual changes in vagally mediated high-frequency power (range −15% to +25%) correlated (r=0.73, P=0.001) with changes in [Vdot]O2max (range −9% to +6%) and changes in testosterone concentration (range −52% to +43%; r=0.43, P=0.047). The mean values of [Vdot]O2max and testosterone concentration did not change during the study period. Measurements of autonomic function could be a useful tool for indicating adaptation to the highly stressful conditions associated with basic military training.

Occupational stress and the outcome of basic military training

Military training has a high dropout rate but the role of occupational stress is not known. To examine the relationship between occupational stress and outcome of training. A study of occupational stress in 476 army recruits (as measured in Week 4 of 23 weeks of basic military training) using previously identified risk factors for lack of success in training and outcome of training. Using stepwise logistic regression, occupational stress levels as measured at Week 4 were significant predictors of outcome in training. Psychological scale scores predicted 85% of those who were asked to leave. Other factors previously thought to be predictive of outcome of training were not predictive in this cohort of recruits. Levels of occupational stress measured 4 weeks into training predicted outcome of training.

Effect of 4 weeks of basic military training on peripheral blood leucocytes and urinary excretion of catecholamines and cortisol

In this study, we assessed the effects of a 4 week basic military physical training programme for male recruits of the Hellenic Air Force on the number and distribution of circulating immune cells and adrenergic and adrenocortical hormonal responses. One group of recruits (exercised, n = 48) participated in moderate intermittent physical exercise, whereas a second group (non-exercised controls, n = 9) performed only light work in the barracks. Both groups participated in the same non-physical, classroom-type training and testing. Military training by the exercised group resulted in significant increases in CD4 + T-lymphocytes, renal cortisol excretion and the urinary noradrenaline/adrenaline ratio, together with reductions in neutrophils and the neutrophil/lymphocyte ratio. In the exercised group, the urinary noradrenaline/adrenaline ratio correlated positively with the training-induced changes in CD4 + T-lymphocytes and negatively with changes in the neutrophil/lymphocyte ratio. No significant relationship was found between training-induced increases in cortisol excretion and any of the peripheral blood cell alterations. Our results indicate that 4 weeks of military training consisting of intermittent moderate exercise resulted in a significant increase in CD4 + T-lymphocytes and reduction in neutrophils. These changes were probably driven by alterations in hormonal status, including the significant impact of sympathetic nervous system activation.