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IntroductionHabitual smoking is highly prevalent in military populations despite its association with poorer training outcomes. Smoking imposes challenges on the immune and endocrine systems which could alter how smokers acutely respond to, and recover from, intensive exercise particularly over multiple days of training.MethodsOver a two-day period, 35 male British Army recruits (age 22±3 years; mass 76.9±8.0 kg; height 1.78±0.06 m; 15 smokers) completed a 16.1 km loaded march (19.1 kg additional mass) on the first morning and a best-effort 3.2 km‘log race’(carrying a 60 kg log between six and eight people) on the subsequent morning. Blood samples were obtained on waking and immediately postexercise on both days and analysed for C reactive protein (CRP), interleukin 6 (IL-6), testosterone to cortisol ratio and insulin-like growth factor 1 (IGF-1).ResultsIndependent of smoking group, the exercise bouts on both days evoked significant increases in IL-6 (p0.05).ConclusionsMilitary-specific tasks elicited inflammatory and endocrine responses, with systemic CRP and IGF-1 indicating that the physiological stress generated during the first training day was still evident on the second day. Despite the well-established impacts of smoking on resting levels of the markers examined, responses to two days of arduous military-specific training did not differ by smoking status.

A plethora of empirical data support a positive (or “brighter”) pathway to optimal human functioning as specified within Basic Psychological Needs Theory (Ryan and Deci in Psychol Inq 11(4):319–33, 2000). Yet, far less is known about the negative (or “darker”) pathway, a process evoking of human dysfunction and ill-being (cf. Vansteenkiste and Ryan in J Psychother Integr 23(3):263, 2013). Further, debate surrounds the independence and interplay between psychological need satisfaction and psychological need frustration and how these dynamic constructs are experienced within individuals. In this work, variable and person-oriented analyses were employed to: (i) investigate the relationships between the basic psychological needs and symptoms of stress, depression and anxiety as well as with life satisfaction; and (ii) identify different psychological need profiles and their relationship with psychological function. Participants (N = 2236; M Age = 42.16 years; SD = 7.8) were UK-based operational firefighters who completed an online survey. Results of regression analyses showed a moderating effect of psychological need satisfaction on the relationship between need frustration and negative psychological symptoms. Latent profile analyses revealed five distinct basic psychological need profiles that carry implications for human psychological functioning. Some support for an asymmetrical relationship between need satisfaction and need frustration emerged (Vansteenkiste and Ryan in J Psychother Integr 23(3):263, 2013), yet, examples of above average need satisfaction and frustration scores were also observed. Worker profiles where psychological need frustration prevailed over need satisfaction had the poorest psychological health.

Wearable physical activity (PA) monitors have improved the ability to estimate free-living total energy expenditure (TEE) but their application during arduous military training alongside more well-established research methods has not been widely documented. This study aimed to assess the validity of two wrist-worn activity monitors and a PA log against doubly-labelled water (DLW) during British Army Officer Cadet (OC) training. For 10 days of training, twenty (10 male and 10 female) OCs (mean ± SD: age 23 ± 2 years, height 1.74 ± 0.09 m, body mass 77.0 ± 9.3 kg) wore one research-grade accelerometer (GENEActiv, Cambridge, UK) on the dominant wrist, wore one commercially-available monitor (Fitbit SURGE, USA) on the non-dominant wrist and completed a self-report PA log. Immediately prior to this 10-day period, participants consumed a bolus of DLW and provided daily urine samples, which were analysed by mass spectrometry to determine TEE. Bivariate correlations and limits of agreement (LoA) were employed to compare TEE from each estimation method to DLW. Average daily TEE from DLW was 4112 ± 652 kcal·day against which the GENEActiv showed near identical average TEE (mean bias ± LoA: -15 ± 851 kcal day ) while Fitbit tended to underestimate (-656 ± 683 kcal·day ) and the PA log substantially overestimate (+1946 ± 1637 kcal·day ). Wearable physical activity monitors provide a cheaper and more practical method for estimating free-living TEE than DLW in military settings. The GENEActiv accelerometer demonstrated good validity for assessing daily TEE and would appear suitable for use in large-scale, longitudinal military studies.

PURPOSE: To determine whether physical performance adaptation is impaired in smokers during early stages of military training, and to examine some of the putative mechanistic candidates that could explain any impairment.METHODS: We examined measures of oxidative stress (malondialdehyde (MDA), lipid hydroperoxides), inflammation (C-reactive protein (CRP), interleukin-6), antioxidants (Vitamins A, E and carotenes) and hormones (cortisol, testosterone, insulin-like growth factor-1) in 65 male British Army Infantry recruits (mean ± SD age: 21 ± 3 yr; mass: 75.5 ± 8.4 kg; height: 1.78 ± 0.07 m) at week 1, week 5 and week 10 of basic training. Physical performance (static lift, grip strength, jump height, 2.4 km run time and two-minute press up and sit up scores) was examined and lower-leg muscle and adipose cross-sectional area (CSA) and density measured by peripheral Quantitative Computed Tomography.RESULTS: Basic Military training, irrespective of smoking status, elicited improvement in all physical performance parameters (main time effect; P < 0.05) except grip strength and jump height, and resulted in increased muscle area and decreased fat area in the lower leg (P < 0.05). MDA was higher in smokers at baseline, and both MDA and CRP were greater in smokers during training (main group effect; P < 0.05), than non-smokers. Absolute performance measures, muscle characteristics of the lower leg and other oxidative stress, antioxidant, endocrine and inflammatory markers were similar in the two groups.CONCLUSIONS: Oxidative stress and inflammation were elevated in habitual smokers during basic military training, but there was no clear evidence that this was detrimental to physical adaptation in this population over the timescale studied.

Objective: To assess sensitivity and specificity of surrogate physical ability tests as predictors\ud of criterion firefighting task performance and to identify corresponding minimum muscular\ud strength and endurance standards. Methods: Fifty-one (26 male; 25 female) participants\ud completed three criterion tasks (ladder lift, ladder lower, ladder extension) and three\ud corresponding surrogate tests (One-repetition maximum (1RM) seated shoulder press; 1RM\ud seated rope pull-down; repeated 28 kg seated rope pull-down). Surrogate test standards were\ud calculated that best identified individuals who passed (sensitivity; true positives) and failed\ud (specificity; true negatives) criterion tasks. Results: Best sensitivity/specificity achieved were\ud 1.00/1.00 for a 35 kg seated shoulder press, 0.79/0.92 for a 60 kg rope pull-down and 0.83/0.93\ud for 23 repetitions of the 28 kg rope pull-down. Conclusions: These standards represent\ud performance on surrogate tests commensurate with minimum acceptable performance of\ud essential strength-based occupational tasks in UK firefighters.

OBJECTIVE: To assess the validity and reliability of a firefighting simulation test (FFST). METHODS: Sixty-nine operational firefighters completed a best-effort FFST on one occasion and 22 participants completed a further FFST. All participants completed a maximal treadmill test to determine cardiorespiratory fitness (VO2max). RESULTS: Time to complete the FFST demonstrated a strong inverse relationship with VO2max (r = -0.73), although the prediction error was high. Reliability of the FFST was high (r = 0.84, P = 0.01), demonstrating a coefficient of variation of 4.5%. CONCLUSIONS: The FFST demonstrated reasonable validity as a surrogate assessment of cardiorespiratory fitness for firefighting. The FFST also demonstrated good reliability. Given the apparent magnitude of the prediction error, the FFST would be best used as a training tool, rather than as a primary means of assessing cardiorespiratory fitness for firefighting.

Background: Aspects of the work environment influence employee well-being. However, it is unclear how employee lifestyle behaviours, health characteristics and well-being may differ within a broader occupational sector.Aims: To investigate the health characteristics, lifestyle behaviours and well-being of three Fire and Rescue Service (FRS) occupational groups that differ in shift work and occupational demands: operational firefighters (FF), emergency control (EC) and administrative support (AS) workers.Methods: Data were obtained via an online survey using previously validated questionnaires to assess health characteristics, lifestyle behaviours and perceived well-being. Differences between groups were explored, controlling for confounding variables, using analysis of covariance (ANCOVA) methods. Effect sizes are reported where appropriate to demonstrate clinical significance.Results: Four thousand five hundred and sixty-four FRS personnel volunteered, with 3333 (73%) completing the survey out of a total workforce of 60000 (8%). FF reported the lowest prevalence of chronic medical conditions (10%), compared with AS (21%) and EC (19%) workers. Total physical activity (PA) was 66% higher among FF compared with EC and AS workers. Components of sleep and self-rated health were independent predictors of well-being irrespective of FRS role.Conclusions: FF reported the highest levels of PA and highest perceptions of well-being, and the lowest prevalence of obesity and chronic medical conditions, compared with other FRS occupational groups. These findings may be used to inform FRS workplace intervention strategies.

Background: Habitual smoking is prevalent in military populations, but\ud whether smoking status influences physical fitness development during training is\ud not clear.\ud \ud Aims: We investigated the effect of smoking status on physical fitness\ud parameters during initial British Army Infantry training.\ud \ud Methods: Routine measures of physical fitness (2.4 km run time and\ud maximum number of press ups and sit ups in two minutes) were obtained in 1,182\ud male recruits (mean ± SD: age 20 ± 3 y, body mass 70.6 ± 9.8 kg, height 1.77 ± 0.07\ud m; 58% smokers) at weeks 1, 14 and 24 of initial military training. A linear mixed\ud model was used to identify differences in performance between smokers and nonsmokers over time.\ud \ud Results: Non-smokers performed significantly better than smokers in all\ud performance tests (P0.05). Run performance improved by 7% in non-smokers (estimated marginal\ud means with 95% confidence limits; 612 (608-616) s to 567 (562-572) s) and 8% in\ud smokers (622 (619-625) s to 571 (568-575) s). Press up performance improved by\ud 18% in non-smokers (48.3 (47.1-49.4) to 57.0 (55.6-58.3)) and 23% in smokers (44.1\ud (43.2-45.1) to 54.5 (53.3-55.6)) and sit up performance by 15% in non-smokers (57.3\ud (56.3-58.2) to 66.0 (64.9-67.2)) and 18% in smokers (53.8 (53.0-54.6) to 63.3 (62.3-\ud 64.3)).\ud \ud Conclusions: Smokers exhibited lower muscular and cardiorespiratory\ud endurance performance than non-smokers. Unexpectedly however, no significant\ud differences in improvement in performance indices were demonstrated between\ud smokers and non-smokers during military training.

Background Injuries sustained by military recruits during initial training impede training progression and military readiness while increasing financial costs. This study investigated training-related injuries and injury risk factors among British Army infantry recruits.Methods Recruits starting infantry training at the British Army Infantry Training Centre between September 2008 and March 2010 were eligible to take part. Information regarding lifestyle behaviours and injury history was collected using the Military Pre-training Questionnaire. Sociodemographic, anthropometric, physical fitness and injury (lower limb and lower back) data were obtained from Army databases. Univariable and multivariable Cox regression models were used to explore the association between time to first training injury and potential risk factors.Results 58% (95% CI 55% to 60%) of 1810 recruits sustained at least 1 injury during training. Overuse injuries were more common than traumatic injuries (65% and 35%, respectively). The lower leg accounted for 81% of all injuries, and non-specific soft tissue damage was the leading diagnosis (55% of all injuries). Injuries resulted in 122 (118 to 126) training days lost per 1000 person-days. Slower 2.4 km run time, low body mass, past injury and shin pain were independently associated with higher risk of any injury.Conclusions There was a high incidence of overuse injuries in British Army recruits undertaking infantry training. Recruits with lower pretraining fitness levels, low body mass and past injuries were at higher risk. Faster 2.4 km run time performance and minimal body mass standards should be considered for physical entry criteria.

A minimum cardiorespiratory fitness standard was derived for firefighters following a metabolic demands analysis. Design and minimal acceptable performance of generic firefighting task simulations (i.e. hose running, casualty evacuation, stair climb, equipment carry, wild-land fire) were endorsed by a panel of operationally experienced experts. Sixty-two UK firefighters completed these tasks wearing a standard protective firefighting ensemble while being monitored for peak steady-state metabolic demand and cardiovascular strain. Four tasks, endorsed as valid operational simulations by ≥90% of participants (excluding wild-land fire; 84%), were deemed to be a sufficiently valid and reliable basis for a fitness standard. These tasks elicited an average peak steady-state metabolic cost of 38.1 ± 7.8 ml kg−1 min−1. It is estimated that healthy adults can sustain the total duration of these tasks (~16 min) at ≤90% maximum oxygen uptake and a cardiorespiratory fitness standard of ≥42.3 ml kg−1 min−1 would be required to sustain work. Practitioner Summary: A cardiorespiratory fitness standard for firefighters of ≥42.3 ml kg−1 min−1 was derived from monitoring minimum acceptable performance of essential tasks. This study supports the implementation of a routine assessment of this fitness standard for all UK operational firefighters, to ensure safe physical preparedness for occupational performance.