INTRODUCTION:The injury definitions and surveillance methods commonly used in Army basic military training (BMT) research may underestimate the extent of injury. This study therefore aims to obtain a comprehensive understanding of injuries sustained during BMT by employing recording methods to capture all physical complaints. MATERIALS AND METHODS:Six hundred and forty-six recruits were assessed over the 12-week Australian Army BMT course. Throughout BMT injury, data were recorded via (1) physiotherapy reports following recruit consultation, (2) a member of the research team (third party) present at physical training sessions, and (3) recruit daily self-reports. RESULTS:Two hundred and thirty-five recruits had ≥1 incident injury recorded by physiotherapists, 365 recruits had ≥1 incident injury recorded by the third party, and 542 recruits reported ≥1 injury-related problems via the self-reported health questionnaire. Six hundred twenty-one, six hundred eighty-seven, and two thousand nine hundred sixty-four incident injuries were recorded from a total of 997 physiotherapy reports, 1,937 third-party reports, and 13,181 self-reported injury-related problems, respectively. The lower extremity was the most commonly injured general body region as indicated by all three recording methods. Overuse accounted for 79% and 76% of documented incident injuries from physiotherapists and the third party, respectively. CONCLUSIONS:This study highlights that injury recording methods impact injury reporting during BMT. The present findings suggest that traditional injury surveillance methods, which rely on medical encounters, underestimate the injury profile during BMT. Considering accurate injury surveillance is fundamental in the sequence of injury prevention, implementing additional injury recording methods during BMT may thus improve injury surveillance and better inform training modifications and injury prevention programs.

BACKGROUND: Militaries have historically utilised generic physical fitness tests to assess physical readiness, but there has been a recent shift to develop physical employment standards (PES) based on actual job demands. OBJECTIVE: The purpose of this investigation was to characterise the physical demands of critical tasks performed by Royal Australian Air Force (RAAF) personnel to inform PES development. METHODS: Job task analysis were performed for 27 RAAF trades. Criterion tasks were identified through a systematic approach involving workshops and field-observations. The identified tasks were assessed for dominant physical capacity and grouped into movement-based clusters. Psychophysiological measures were collected from personnel performing the tasks. RESULTS: Of 87 criterion tasks, 92% were characterised as manual handling dominant. Across these 87 tasks the principal physical capacities were: muscular strength (59%), muscular endurance (52%) and cardiorespiratory endurance (39%). The most common movement clusters were Lift to Platform (44%) and Lift and Carry (38%). Lift to Platform tasks required lifting to a median height of 1.32 m (1.20 –1.65 m) and a median mass of 25.0 kg (21.0 –28.9 kg) per person. Median carry mass was 25.0 kg (22.4 –36.1 kg) per person and distance was 26.0 m (17.5 –50.0 m). Median task mean ’Vdot;O2, HR and RPE were 1.8 L.min- 1 (1.5–2.2 L.min- 1), 137 b.min- 1 (120–144) and 13 (12–14). CONCLUSIONS: The high proportion of manual handling criterion tasks emphasises the importance of these activities and the underlying physical capacities for RAAF personnel. Current fitness assessments are unlikely to predict job task performance.

This study compared heart rate variability (HRV) parameters of cardiovascular autonomic regulation between well-trained masters and young cyclists at rest, during and following a continuous cycle (CTS) protocol. Ten masters (age = 56 ± 5 years) and eight young (age = 26 ± 3 years) cyclists completed a 100 min experimental protocol consisting of a 60 min CTS cycling bout at 95

Objectives: To investigate: (i) the chronicity and phasic variability of sleep patterns and restriction in recruits during basic military training (BMT); and (ii) identify subjective sleep quality in young adult recruits prior to entry into BMT.Design: Prospective observational study.Methods: Sleep was monitored using wrist-worn actigraphy in Army recruits (n = 57, 18-43 y) throughout 12 weeks of BMT. The Pittsburgh Sleep Quality Index (PSQI) was completed in the first week of training to provide a subjective estimate of pre-BMT sleep patterns. A mixed-effects model was used to compare week-to-week and training phase (Orientation, Development, Field, Drill) differences for rates of sub-optimal sleep (6-7 h), sleep restriction (<= 6 h), and actigraphy recorded sleep measures.Results: Sleep duration was 06:24 +/- 00:18h (mean +/- SD) during BMT with all recruits experiencing sub-optimal sleep and 42% (n = 24) were sleep restricted for >= 2 consecutive weeks. During Field, sleep duration (06:06 +/- 00:36h) and efficiency (71 +/- 6%; p < 0.01) were reduced by 15-18 min (minimum maximum) and 7-8% respectively; whereas, sleep latency (30 +/- 15 min), wake after sleep onset (121 +/- 23 min), sleep fragmentation index (41 +/- 4%) and average awakening length (6.5 +/- 1.6 min) were greater than non-Field phases (p < 0.01) by 16-18 min, 28-33 min, 8-10% and 2.5-3 min respectively. Pre-BMT global PSQI score was 5 +/- 3, sleep duration and efficiency were 7.4 +/- 1.3 h and 88 +/- 9% respectively. Sleep schedule was highly variable at pre-BMT (bedtime: 22:34 +/- 7:46 h; wake time: 6:59 +/- 1:42 h) unlike BMT (2200-0600 h).Conclusions: The chronicity of sub-optimal sleep and sleep restriction is substantial during BMT and increased training demands exacerbate sleep disruption. Exploration of sleep strategies (e.g. napping, night-time routine) are required to mitigate sleep-associated performance detriments and maladaptive outcomes during BMT.(c) 2022 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

This study aimed to quantify sleeping heart rate (HR) and HR variability (HRV) alongside circulating tumor necrosis factor alpha (TNFα) concentrations during 12-week Basic Military Training (BMT). We hypothesised that, despite a high allostatic load, BMT would increase cardiorespiratory fitness and HRV, while lowering both sleeping HR and TNFα in young healthy recruits. Sixty-three recruits (18–43 years) undertook ≥ 2 overnight cardiac frequency recordings in weeks 1, 8 and 12 of BMT with 4 h of beat-to-beat HR collected between 00:00 and 06:00 h on each night. Beat-to-beat data were used to derive HR and HRV metrics which were analysed as weekly averages (totalling 8 h). A fasted morning blood sample was collected in the equivalent weeks for the measurement of circulating TNFα concentrations and predicted VO2max was assessed in weeks 2 and 8. Predicted VO2max was significantly increased at week 8 (+ 3.3 ± 2.6 mL kg−1 min−1; p < 0.001). Sleeping HR (wk1, 63 ± 7 b min−1) was progressively reduced throughout BMT (wk8, 58 ± 6; wk12, 55 ± 6 b min−1; p < 0.01). Sleeping HRV reflected by the root mean square of successive differences (RMSSD; wk1, 86 ± 50 ms) was progressively increased (wk8, 98 ± 50; wk12, 106 ± 52 ms; p < 0.01). Fasted circulating TNFα (wk1, 9.1 ± 2.8 pg/mL) remained unchanged at wk8 (8.9 ± 2.5 pg/mL; p = 0.79) but were significantly reduced at wk12 (8.0 ± 2.4 pg/mL; p < 0.01). Increased predicted VO2max, HRV and reduced HR during overnight sleep are reflective of typical cardiorespiratory endurance training responses. These results indicate that recruits are achieving cardiovascular health benefits despite the high allostatic load associated with the 12-week BMT.

Abstract Drain, JR, Debenedictis, T, Bulmer, S, and Michael, S. comparison of military recruit and incumbent physical characteristics and performance: Potential implications for through-career individual readiness and occupational performance. J Strength Cond Res 36(9): 2536–2543, 2022—After basic military training, physical training practices among incumbent personnel differ substantially, potentially precipitating varied physical capacity and operational readiness. The purpose of this retrospective investigation was to compare physical characteristics and physical performance between recruits and incumbent personnel. Data were collected for 222 army recruits (REC: 197 men/25 women) nearing completion of basic training and 280 incumbent army personnel from combat arms (CA: 142 men) and noncombat arms trades (NCA: 113 men/25 women). Height, mass, and body mass index (BMI) were recorded together with performance measures including predicted V̇o 2max and 1 repetition maximum box lift. Compared with REC, male incumbents were older (21.8 ± 0.6 vs. 27.6 ± 1.2 years; mean ± 95% confidence interval), had greater body mass (77.6 ± 1.3 vs. 82.6 ± 1.5 kg) and BMI (24.2 ± 0.3 vs. 25.8 ± 0.5 kg·m−2), similar relative V̇o 2max, and lower box lift (49.7 ± 1.4 vs. 47.2 ± 2.4 kg). Male CA demonstrated greatest physical performance while male NCA demonstrated the highest BMI and poorest physical performance. Compared with REC, female incumbents were older (22.8 ± 1.6 vs. 31.9 ± 4.4 years), had similar body mass, higher BMI (24.1 ± 0.7 vs. 26.1 ± 2.4 kg·m−2), as well as lower V̇o 2max (42.0 ± 1.3 vs. 37.9 ± 2.1 ml·kg·−1·min−1) and box lift (27.8 ± 2.1 vs. 23.3 ± 2.4 kg). More than 97% of men and approximately 75% of women were able to achieve the box lift and V̇o 2max baseline standards. The older age category (26 + vs. 18–25 years) typically demonstrated higher BMI and lower physical performance. Through-career maintenance of physical capacity is important for military personnel to support individual readiness and occupational performance, preserve health, and mitigate musculoskeletal injury risk.

Military personnel are required to complete physically demanding tasks when performing work and training, which may be quantified through the physical stress imposed (external load) or the resultant physiological strain (internal load). The aim of this narrative review is to provide an overview of the techniques used to monitor work and training load in military settings, summarise key findings, and discuss important practical, analytical, and conceptual considerations. Most investigations have focused upon measuring external and internal load in military training environments; however, limited data exist in operational settings. Accelerometry has been the primary tool used to estimate external load, with heart rate commonly used to quantify internal load. Supplemental to heart rate, psychophysiological and biochemical measures have also been investigated to elucidate aspects of internal load. Broadly, investigations have revealed that military training requires personnel to perform relatively large volumes of physical activity (e.g. averaging ∼15,000 steps·day-1) of typically low-moderate intensity activity (<6 MET), although considerable temporal and inter-individual variability is observed from these gross mean estimates. There are limitations associated with these measures and, at best, estimates of external and internal load can only be inferred. These limitations are particularly pertinent for military tasks such as load carriage and manual material handling, which often involve complex activities performed individually or in teams, in a range of operational environments, with multiple layers of protection, over a protracted duration. Comprehensively quantifying external and internal loads during these functional activities poses substantial practical and analytical challenges.

Abstract The root mean square of successive differences (RMSSD) of R-R intervals, the most robust vagal modulation parameter of heart rate variability (HRV), has been proposed as a marker of global health and training adaptations. The weekly averaging of RMSSD and its natural logarithm (LnRMSSD) has been adopted to enhance detection of training-induced adaptations. We assessed measures of aerobic fitness, body composition, objective physical activity (PA), and daily LnRMSSD recordings during different conditions, such as supine rest, seated rest, standing and walking at 5 km/h, over a week in 34 healthy young individuals of both sexes (age: 22 ± 4 yr; body fatness: 20 ± 8%; estimated VO2max: 40 ± 8 mL·kg−1·min−1). The day-to-day reliability and agreement among LnRMSSD averages over 5, 4, 3, 2 and a single-day value per condition were assessed, while correlations between LnRMSSD, aerobic fitness, body composition, and PA were also examined. Poor to good day-to-day reliability, and moderate to excellent agreement were observed for LnRMSSD recordings for diverse conditions with a minimum of two daily recordings in the supine condition, and three in the other conditions achieving excellent agreement for weekly HRV assessment. Several correlations between LnRMSSD, aerobic fitness, body composition, and PA were revealed, with stronger observed associations during walking. Utilisation of weekly HRV (average of 2–3 daily recordings), as described in the current study, may provide practitioners with a tool to assess weekly vagal modulations for health and performance purposes. Walking HRV recordings may be a practical alternative to other conditions for the investigation of cardiac autonomic function.

ABSTRACT Dog ownership is often advocated for its potential benefits to human health, with changes to oxytocin and autonomic nervous system (ANS) activity proposed as possible underlying mechanisms. The aims of the current study were to a) examine the effect of two common types of human–dog interactions (dog-walking and affiliative interactions) on salivary oxytocin concentrations and heart rate variability (HRV, an indicator of ANS activity), and b) investigate any putative moderating role for the strength of human–dog attachment on such responses. Twenty-nine dog owners completed a four-condition random-order cross-over trial: dog-walking (DW); walking without the dog (W); affiliative human–dog interaction (H-DI); and resting without the dog (C). Each condition was performed for approximately 15 minutes. Saliva and HRV samples were collected before and after each condition. Linear mixed models were used to analyze data, with the participant considered a random effect; condition, order of conditions, and condition duration as fixed effects. Oxytocin concentrations were not significantly different following any of the four conditions. HRV was significantly reduced following DW (mean change HF HRV = –0.37, 95% CI = –0.70, –0.04) and W (mean change HF HRV = –0.49, 95% CI = –0.81, –0.17). Considering moderation by the strength of the human–dog bond, pairwise comparisons revealed that, compared with W, DW elicited an increase in oxytocin concentrations (mean change 9.32 pg/mL, 95% CI = 6.52, 12.12) and HRV (mean change SDRR = 0.41, 95% CI = 0.19, 0.63) in owners with lower levels of attachment. These owners also displayed increased oxytocin concentrations following H-DI (mean change 3.90 pg/mL, 95% CI = 1.48, 6.32), compared with C. Overall, we did not find a consistent pattern for positive oxytocin or HRV responses to human–dog interactions. The strength of owner–dog attachment was found to have a moderating effect, suggesting that human–dog interactions may elicit greater physiological responses in low-attachment individuals.

Previous studies conducted with athletes have suggested a minimum of 3 days are required for identifying training induced adaptations in supine, morning, resting heart rate variability (HRV). However, there are no studies evaluating the minimum days required for appropriate reliability of HRV measures in non-athletes, and during different conditions of evaluation. PURPOSE: 1) To evaluate the reliability of a prominent HRV measure, the root mean square of the successive differences of R-R intervals (RMSSD), during different conditions in non-athletes; 2) to identify the minimum number of days required for weekly (5-day) evaluations of RMSSD. METHODS: Thirty-four young, physically active individuals (22.2±3.6 years) completed daily 4-min R-R recordings during supine, seated, standing and walking (5 km/h) conditions over 5 days. Relative (intraclass correlation coefficients, ICC) and absolute (technical error of measurement, TEM; coefficient of variation, %CV) reliability, and bias were calculated for 1, 2, 3, and 4 days, and compared with weekly (5 days) assessments. RESULTS: Excellent reliability was identified for all conditions over 4 days (ICC≥0.986, CV≤2.8%) that was diminished when examined over 3 (ICC≥0.970, CV≤3.4%), 2 (ICC≥0.932, CV≤5.7%) and 1 (ICC≥0.804, CV≤10.2%) day. When compared with weekly recordings, 2 day recordings demonstrated excellent and similar reliability values for all conditions examined, with better values observed for supine vs. seated vs. standing vs. walking conditions. CONCLUSIONS: From the current results, daily assessment of RMSSD is highly reliable with a minimum of 2 days of recordings recommended for determination of weekly HRV in non-athletes, regardless of the condition.

Purpose: Implementation of employer sun safety actions was assessed in a 2-year follow-up to an occupational sun protection policy intervention. Design: Two-year follow-up assessment in a randomized pretest–posttest controlled design. Setting: Local government organizations with workers in public safety, public works, and parks and recreation. Participants: Sixty-three local government organizations (participation = 64%) and 330 frontline supervisors and 1454 workers. Intervention: Sun Safe Workplaces (SSW) intervention promoting occupational sun safety policy and education. Measures: Observations of SSW messages and sun safety items and surveys on organizations’ communication and actions on sun safety. Analysis: Comparison between SSW and control groups was conducted using regression models and adjusted for clustering where appropriate, with α criterion set at P = .05 (2-tailed). Results: At intervention worksites, more SSW messages ( P < .001) and sun safety items ( P = .025) were observed; more frontline supervisors reported organizations provided free/reduced price sunscreen ( P = .005) and communicated about sun safety ( P < .001); and more workers recalled receiving sun safety messages ( P < .001) and sun safety training ( P <.001) compared to control organizations. Implementation was greater at larger than smaller intervention organizations for wide-brimmed hats ( P = .009), long work pants ( P = .017), and shade structures ( P = .036). Older workers received the most written messages ( P = .015). Conclusions: Sun Safe Workplaces appeared to produce actions by organizations to support employee sun safety. Large organizations may have processes, communication channels, and slack resources to achieve more implementation.

Objective: Occupational skin cancer prevention is a priority because outdoor workers are exposed to high levels of ultraviolet radiation, the primary risk factor for skin cancer. Methods: A 2-year follow-up assessment of the impact of Sun Safe Workplaces (SSW), a workplace sun safety program that promoted policy adoption and education, on employee sun safety behavior was conducted. Sixty-three of 98 local government organizations from the original study participated. Results: Outdoor workers (n = 1724) completed surveys on personal sun protection practices. Employees’ sun protection improved statistically significantly in the intervention group receiving the SSW program. SSW's effect was mediated by the number of workplace actions to implement elements of the policy, including sun protection messages and equipment and employee reports of sun safety training. Conclusion: Policy promotion is a feasible approach to occupational skin cancer prevention.

Objectives: This study investigated indirect measures of post-exercise parasympathetic reactivation (using heart-rate-variability, HRV) and sympathetic withdrawal (using systolic-time-intervals, STI) following upper- and lower-body exercise. Design: Randomized, counter-balanced, crossover. Methods: 13 males (age 26.4 +/- 4.7 years) performed maximal arm-cranking (MAX-ARM) and leg-cycling (MAX-LEG). Subsequently, participants undertook separate 8-min bouts of submaximal HR-matched exercise of each mode (ARM and LEG). HRV (including natural-logarithm of root-mean-square of-successive-differences, Ln-RMSSD) and STI (including pre-ejection-period, PEP) were assessed throughout 10-min seated recovery. Results: Peak-HR was higher (p = 0.001) during MAX-LEG (182 +/- 7 beats min(-1)) compared with MAX-ARM (171 +/- 12 beats min(-1)), while HR (p < 0.001) and Ln-RMSSD (p = 0.010) recovered more rapidly following MAX-ARM. PEP recovery was similar between maximal bouts (p = 0.106). HR during submaximal exercise was 146 +/- 7 (LEG) and 144 +/- 8 beats min(-1) (LEG) (p = 0.139). Recovery of HR and Ln-RMSSD was also similar between submaximal modalities, remaining below baseline throughout recovery (p < 0.001). PEP was similar during submaximal exercise (LEG 70 +/- 6 ms; ARM 72 +/- 9 ms; p = 0.471) although recovery was slower following ARM (p = 0.021), with differences apparent from 1- to 10-min recovery (p <= 0.036). By 10-min post-exercise, PEP recovered to baseline (132 +/- 21 ms) following LEG (130 +/- 21 ms; p = 0.143), but not ARM (121 +/- 17 ms; p = 0.001). Conclusions: Compared with submaximal lower-body exercise, HR-matched upper-body exercise elicited a similar recovery of HR and HRV indices of parasympathetic reactivation, but delayed recovery of PEP (reflecting sympathetic withdrawal). Exercise modality appears to influence post-exercise parasympathetic reactivation and sympathetic withdrawal in an intensity-dependent manner. These results highlight the need for test standardization and may be relevant to multi-discipline athletes and in clinical applications with varying modes of exercise testing. (C) 2018 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Purpose: To evaluate an intervention promoting adoption of occupational sun protection policies by employers in a randomized trial. Design: A randomized pretest–posttest controlled design with 2-year follow-up was conducted in 2010 to 2013. Setting: Local government organizations in Colorado who had outdoor workers in public works, public safety, and/or parks and recreation. Participants: Ninety-eight local government organizations (n = 51 municipalities, 10 counties, and 37 special districts). Intervention: Organizations were randomly assigned to receive a policy and education intervention comprised of personal contacts and theory-based training and materials or to an attention control group. Measures: Occupational policy documents were coded for sun safety content by a trained research assistant blind to condition. Analysis: Policy scores were analyzed with logistic and Poisson regression models using imputation. Results: At posttest, more organizations in the intervention group had a sun protection policy than in the control group (odds ratio [OR] = 4.91, P < .05; intent to treat: OR = 5.95, P < .05) and policies were more extensive (χ 2 = 31.29, P < .01; intent to treat: χ 2 =73.79, P < .01) and stronger (χ 2 = 24.50, P < .01; intent to treat: χ 2 = 51.95, P < .01). Policy adoption was higher when the number of contacts and trainings increased ( P < .05). Conclusion: The intervention had a large effect on adoption of formal sun protection policies, perhaps because of its fit with legal requirements to maintain safe workplaces. Personal contacts with managers were influential on adoption of occupational policy even in this age of communication technology and social media.

The purpose of this systematic review and meta-analysis is to assess the effect of concurrent high intensity interval training (HIIT) and resistance training (RT) on strength and hypertrophy. Five electronic databases were searched using terms related to HIIT, RT, and concurrent training. Effect size (ES), calculated as standardised differences in the means, were used to examine the effect of concurrent HIIT and RT compared to RT alone on muscle strength and hypertrophy. Sub-analyses were performed to assess region-specific strength and hypertrophy, HIIT modality (cycling versus running), and inter-modal rest responses. Compared to RT alone, concurrent HIIT and RT led to similar changes in muscle hypertrophy and upper body strength. Concurrent HIIT and RT resulted in a lower increase in lower body strength compared to RT alone (ES=-0.248, p=0.049). Sub analyses showed a trend for lower body strength to be negatively affected by cycling HIIT (ES=-0.377, p=0.074) and not running (ES=-0.176, p=0.261). Data suggests concurrent HIIT and RT does not negatively impact hypertrophy or upper body strength, and that any possible negative effect on lower body strength may be ameliorated by incorporating running based HIIT and longer inter-modal rest periods.

Driving may be detrimental to health, with one hypothesis suggesting that driving may elicit an acute stress response and, with repeated exposures, may become a chronic stressor. The present study examined the stress response to driving and the effectiveness of a prior exercise bout in dampening this response. Twenty healthy adults performed three tasks: control, driving and exercise plus driving. Heart rate (HR), heart rate variability (HRV), blood pressure (BP) and cortisol were measured to quantify the acute stress response to each condition. Data indicated a stress response to driving: HR was elevated and HRV was reduced during the driving task compared with control. HR was elevated and HRV was reduced comparing the exercise plus driving with the driving condition. BP and cortisol were not different among conditions. The potential of interventions, such as exercise, to counter daily stressors should be evaluated to safeguard long-term health. Practitioner Summary: this study confirms that driving induces a stress response, with the exercise intervention providing mixed results (an increase in cardiovascular measures and a decrease in cortisol measure trending significance). Given the known consequences of stress and evidence that exercise can mitigate acute stress, further evaluation of exercise interventions is recommended.

Objective: Occupational skin cancer prevention is a priority because outdoor workers are exposed to high levels of ultraviolet radiation, the primary risk factor for skin cancer. Methods: A 2-year follow-up assessment of the impact of Sun Safe Workplaces (SSW), a workplace sun safety program that promoted policy adoption and education, on employee sun safety behavior was conducted. Sixty-three of 98 local government organizations from the original study participated. Results: Outdoor workers (n = 1724) completed surveys on personal sun protection practices. Employees' sun protection improved statistically significantly in the intervention group receiving the SSW program. SSW's effect was mediated by the number of workplace actions to implement elements of the policy, including sun protection messages and equipment and employee reports of sun safety training. Conclusion: Policy promotion is a feasible approach to occupational skin cancer prevention.