Physiological responses to simulated firefighter exercise protocols in varying environments

Evaluation of self-contained breathing apparatus (SCBA) weight on firefighter stamina, comfort, and postural stability

Firefighters wear personal protective equipment to protect them from the thermal and chemical environment in which they operate. The self-contained breathing apparatus (SCBA) provides isolation of the airway from the hazardous fireground. National standards limit SCBA weight, however, integration of additional features could result in an SCBA exceeding the current limit. The purpose of this study was to examine the effects of increased SCBA weight on firefighters' physiological responses, work output, dynamic stability, and comfort. Completion of simulated firefighting activities induced a strong physiological response. Peak oxygen consumption was higher with the lightest SCBA than the heaviest SCBA. Few other physiological differences were noted as SCBA weight increased. Importantly, increased SCBA weight resulted in significantly more negative perceptions by the firefighters and a trend towards significance for the duration of work time prior to reaching volitional fatigue. These results should be considered when assessing changes to existing SCBA weight limits.

Physiological Stress Responses to a Live-Fire Training Evolution in Career Structural Firefighters

OBJECTIVE

This study assessed firefighters' physiological stress response to a live fire training evolution (LFTE).

METHODS

Seventy-six ( n = 76) firefighters completed an LFTE. Salivary samples were collected pre-, immediately post, and 30-min post-LFTE and analyzed for α-amylase (AA), cortisol (CORT), and secretory immunoglobulin-A (SIgA).

RESULTS

Concentrations of AA, CORT, and SIgA were elevated immediately post LFTE versus pre (P<0.001) and 30-min post (P<0.001). Cohen's d effect size comparing pre and immediately-post means were 0.83, 0.77, and 0.61 for AA, CORT, and SIgA and were 0.54, 0.44, and 0.69 for AA, CORT, and SIgA, comparing immediately-post and 30-min post, respectively.

CONCLUSIONS

These data demonstrate the stress response and activation of the hypothalamic-pituitary-adrenal/sympathetic-adreno-medullar axis and immune system immediately after real-world firefighting operations. Future work is needed to understand the impact of elevated stress biomarkers on firefighter performance and disease risk.

Metabolic demands of a simulated smoke-diving drill

The main goal of this study was to update the Finnish smoke-diving drill (FSDD) and to measure the physical strain of and recovery from the drill. Furthermore, the aim was to compare the physical strain of contract and professional firefighters and effect of floor materials. The associations between aerobic capacity and physical strain were also studied. The updates made included an added hose pull task and updating the equipment used. Heart rate (HR), oxygen consumption (V̇O2), and blood lactate concentration ([La-]) of 32 professional and 5 contract firefighters were measured before, during, and 10 and 30 min after the updated drill. The mean HR during the drill was 78% and V̇O2 59% of maximum. HR and [La-] had not recovered to baseline levels after 30-minute recovery period. Physical strain was higher among contract firefighters and [La-] accumulation on rough floor surfaces. Better aerobic capacity was associated with reduced physical strain.

Firefighter Health: A Narrative Review of Occupational Threats and Countermeasures

Structural firefighters are responsible for protecting properties and saving lives during emergency operations. Despite efforts to prepare firefighters for these hazardous occupational demands, the unfortunate reality is that the incidence of health morbidities is increasing within the fire service. Specifically, cardiovascular disease, cancer, and mental health disorders are among the most documented morbidities in firefighters. Pubmed and Google Scholar search engines were used to identify peer-reviewed English language manuscripts that evaluated firefighters' occupational health threats, allostatic factors associated with their occurrence, and evidence-based strategies to mitigate their impact. This narrative review provides fire departments, practitioners, and researchers with evidence-based practices to enhance firefighters' health.

Heat strain of Japanese firefighters wearing personal protective equipment: a review for developing a test method

The aim of this review was to develop a test method for the evaluation of heat strain for structural firefighters wearing personal protective equipment (PPE) in Japan. We analysed a series of our laboratory's questionnaires and experimental studies and reviewed international standards on test methods. We investigated the actual average working conditions (total firefighting time on one incidence, working time with full PPE, maximum temperature and humidity during firefighting) at structural firefighting site in Japan by conducting a large-scale questionnaire survey of Japanese firefighters. We discussed test subjects (firefighters vs. non-firefighters; body size; physical fitness), exercise intensity (absolutes vs. relative; light vs. heavy) and duration, experimental temperature and relative humidity, experimental clothing items including station uniforms (shorts vs. long), and measurement variables (physiological and subjective responses), and suggested a standard test method to evaluate the heat strain of firefighters in hot and humid environments.Practitioner summary: We reviewed studies on human wear trials of firefighting personal protective equipment (PPE) in hot environments and suggested a standard test method to evaluate the heat strain of firefighters. The test method can be internationally utilised to examine the comfort functions and heat stress of PPE in hot, humid environments.

Use of accelerometers and inertial measurement units to quantify movement of tactical athletes: A systematic review

The dynamic work environments of tactical athletes are difficult to replicate in a laboratory. Accelerometers and inertial measurement units provide a way to characterize movement in the field. This systematic review identified how accelerometers and inertial measurement units are currently being used to quantify movement patterns of tactical athletes. Seven research and military databases were searched, producing 26,228 potential articles with 78 articles included in this review. The articles studied military personnel (73.1%), firefighters (19.2%), paramedics (3.8%), and law enforcement officers (3.8%). Accelerometers were the most used type of sensor, and physical activity was the primarily reported outcome variable. Seventy of the studies had fair or poor quality. Research on firefighters, emergency medical services, and law enforcement officers was limited. Future research should strive to make quantified movement data more accessible and user-friendly for non-research personnel, thereby prompting increased use in tactical athlete groups, especially first responder agencies.

Exploring First Responders' Use and Perceptions on Continuous Health and Environmental Monitoring

First responders lose their lives in the line of duty each year, and many of these deaths result from strenuous physical exertion and exposure to harmful environmental agents. Continuous health monitoring may detect diseases and alert the first responder when vital signs are reaching critical levels. However, continuous monitoring must be acceptable to first responders. The purpose of this study was to discover first responders' current use of wearable technology, their perceptions of what health and environmental indicators should be monitored, and who should be permitted to monitor them. The survey was sent to 645 first responders employed by 24 local fire department stations. A total of 115 (17.8%) first responders answered the survey and 112 were used for analysis. Results found first responders perceived a need for health and environmental monitoring. The health and environmental indicators that respondents perceived as most important for monitoring in the field were heart rate (98.2%) and carbon monoxide (100%), respectively. Overall, using and wearing monitoring devices was not age-dependent and health and environmental concerns were important for first responders at any stage of their career. However, current wearable technology does not seem to be a viable solution for first responders due to device expense and durability issues.

Wilderness First Responder Medical Clearance - A Scoping Review with Recommendations

BACKGROUND AND PURPOSE

Due to environmental extremes, as well as the nature of the work itself, wilderness first responders are at risk of incurring medical events in the line of duty. There currently do not exist standardized and scientifically supported methods to screen for a wilderness first responder's risk of incurring a medical event.

METHODS

We performed multiple scoping reviews using PubMed and CINAHL. The reviews covered six medical screening criteria based on previous recommendations from the National Fire Protection Association (NFPA) and the US Forest Service, and we grouped our reviews into two categories: articles that addressed objective screening criteria, and articles that addressed subjective findings with the first responder.

RESULTS

Of the objective criteria, our reviews identified 21 articles addressing the ability to screen for risk of incurring a medical event by evaluation of a first responder's heart rate, 12 by blood pressure assessment, and 56 by assessment of body temperature. Of the subjective criteria we identified 19 articles focused on self-assessment, 34 articles on the use of standardized tools to assess for fatigue and sleepiness, and two articles on assessment of a first responder's urine to determine level of dehydration. We also identified seven additional articles through a hand search. Overall, there were 151 articles identified in our scoping reviews. These articles were largely of low quality, consisting mostly of case series without comparison groups.

CONCLUSION

There is a dearth of high-quality research into the medical assessment of first responders. We recommend that this paper, and measures discussed within it, be used as a starting point in the development of an evidence-based assessment protocol for wilderness first responders. We also recommend the development of a national database of medical events incurred by wilderness first responders to facilitate higher-quality research of screening protocols in this community.

The effects of personal protective equipment on heart rate, oxygen consumption and body temperature of firefighters: A systematic review

BACKGROUND

Fire extinguishing operations are carried out by firefighters equipped with personal protective equipment (PPE) in dangerous environments. Although PPE protects firefighters, it can affect many physiological parameters.

OBJECTIVE

This study aimed to investigate the effects of PPE on firefighters' heart rate (HR), oxygen consumption (OC) and body temperature (BT).

METHODS

This systematic review thoroughly reviewed relevant articles in the reliable databases "Web of Science", "Embase", "IranDoc", "IranMedex", "SID", "Magiran", "Google Scholar", "PubMed" and "Scopus" from 2010 to 2021. Some of the used search terms were "firefighters", "personal protective equipment", "heart rate" and "oxygen consumption".

RESULTS

Out of the 405 studies identified through the systematic search, 18 articles were eligible according to the Joanna Briggs Institute (JBI) checklist, among which 11 studies were conducted in North America, three in Asia, two in Europe, and two studies in Oceania. According to the review of studies, PPE increased HR, BT, and OC. The type of PPE components, the weight of the equipment, the kind of activity of firefighters, and weather conditions were among the influencing parameters on the extent of PPE's influence on these physiological parameters.

CONCLUSION

The results of the studies show that PPE separately and collectively affects the physiological parameters of HR, BT and OC. To reduce these effects, it is necessary to pay attention to several items, including the weight of PPE, the type of PPE ingredients in different weather conditions, and the type of activities of firefighters in PPE design.

Utilizing multimodal high-intensity interval training for a firefighter training academy during the COVID-19 pandemic

BACKGROUND

Firefighters typically undergo a 16-24-week training academy during which they perform a variety of traditional exercise programs such as cardiovascular, resistance, and concurrent training. Because of limited facility access, some fire departments seek alternative exercise programs, such as multimodal high-intensity interval training (MM-HIIT), which essentially combines resistance and interval training.

OBJECTIVE

The primary purpose of this study was to assess the effect of MM-HIIT on body composition and physical fitness in firefighter recruits who completed a training academy during the coronavirus (COVID-19) pandemic. A secondary purpose was to compare the effects of MM-HIIT to previous training academies that implemented traditional exercise programs.

METHODS

Healthy and recreationally-trained recruits (n = 12) participated in 2-3 days/week of MM-HIIT for 12 weeks and had several components of body composition and physical fitness measured before and after the program. Because of COVID-19-related gym closures, all MM-HIIT sessions were performed outdoors at a fire station with minimal equipment. These data were retroactively compared to a control group (CG) that previously completed training academies with traditional exercise programs.

RESULTS

Subjects in the MM-HIIT group significantly improved several components of body composition and fitness, including fat mass, fat-free mass, body fat percentage, aerobic capacity, and muscular endurance. Moreover, there were no significant differences for any dependent variable when MM-HIIT was compared to the CG.

CONCLUSION

These results suggest that MM-HIIT may serve as an effective substitute for traditional concurrent training paradigms that are typically used for firefighter academies.

Gait Adaptations to Physical Fatigue During the Negotiation of Variable and Unexpected Obstacles

OBJECTIVE

The purpose of this study was to investigate how physical fatigue impacts one's ability to negotiate unexpected and randomly located obstacles during locomotion.

BACKGROUND

Physically demanding occupations place workers at risk of trips and falls-a major health and financial burden. How worker physical fatigue and fitness impacts their ability to navigate through unpredictable environments is not thoroughly explored in current literature. In this exploratory study, we further examine these relationships.

METHODS

Twenty-one young, physically fit participants completed a series of obstacle negotiation trials in the dark, where an obstacle would suddenly be illuminated as they reached it. Participants then engaged in a fatigue protocol, before repeating a series of the same negotiation trials.

RESULTS

When fatigued, participants exhibited a significant decrease in leading toe and trailing toe clearance, as well as a significant increase in leading heel clearance. Moreover, participants stepped closer to the obstacle with their both feet on the step prior to negotiation. Participants also walked at a faster velocity. Regression analyses revealed that participants' VO2max and height were significant predictors of foot placement metrics.

CONCLUSION

Results indicate that physical fatigue negatively impacts crossing mechanics of young, healthy individuals, and that a higher level of VO2 capacity may reduce the occurrences of altered crossing behavior that coincide with physical fatigue.

APPLICATION

These results highlight the effect of fatigue on worker safety during performance of job-related duties and are of interest to professionals seeking to reduce the incidence of slips, trips, and falls in the workplace.

The influence of team workload on team performance in the light of task complexity: a study of nuclear fire brigades

The aim of our experiment was to explore the effect of perceived team workload on team performance among nuclear fire brigades of the Hungarian Nuclear Power Plant. Our sample consisted of 6 firefighting teams (N = 42) who were involved in two high-fidelity simulated scenarios with different task complexity. Team workload was measured by NASA Task Load Index, while team performance was evaluated by a team of experts. Our results showed that teams generally managed to maintain a standard performance in both cases, although they perceived there to be a higher workload during the complex scenario. Our results further revealed that perceived 'Physical demand' and 'Effort' factors contributed to the increased level of workload in the complex task. Finally, in case of the simple simulated scenario, workload and team performance were not related to each other, while the two were positively correlated in the complex scenario.

Acute Physiological Response of Live-Fire Simulation Activities Affecting Cardiovascular Health in Live-Fire Instructors: A Randomized Controlled Simulation Study

OBJECTIVES

This study aimed to assess acute physiological response of fire suppression simulation affecting cardiovascular health during repeated bouts of simulation.

METHODS

Fifteen live-fire instructors were randomly divided into three groups according to fire suppression simulation frequency. Vital signs, biomarkers, and heart rate variability (HRV) were measured before and after simulation.

RESULTS

Vital signs increased immediately after fire simulation and returned to the normal range after 2 h. Most biomarker levels were changed within the normal ranges 72 h after the simulation training. However, one of the HRV frequency domains, high frequency power, was severely suppressed after 1 h and tended to recover after 2 h of simulation (P < 0.05).

CONCLUSIONS

Vital signs and their biomarkers were changed within the normal range regardless of the number of bouts of fire suppression simulations. HRV could be used to assess the effects of fire suppression simulation on cardiovascular health.

Altered Spatiotemporal Gaze Dynamics During Unexpected Obstacle Negotiation in a Fatigued State

Humans use their peripheral vision during locomotion to perceive an approaching obstacle in their path, while also focusing central gaze on steps ahead of them. However, certain physiological and psychological factors may change this strategy, such as when a walker is physically fatigued. In this study, 21 healthy participants walked through a dark room while wearing eye tracking glasses before and following intense exercise. Obstacles were placed in random locations along their path and became illuminated when participants approached them. Results indicate that, when fatigued, participants had altered spatial gaze strategies, including more frequent use of central gaze to perceive obstacles and an increased gaze angular displacement. However, there were no changes in temporal gaze strategies following exercise. These findings reveal how physical fatigue alters one's visual perception of their environment during locomotion, and may partially explain why people are at greater risk of trips and falls while fatigued.

Applicability of Physiological Monitoring Systems within Occupational Groups: A Systematic Review

The emergence of physiological monitoring technologies has produced exceptional opportunities for real-time collection and analysis of workers' physiological information. To benefit from these safety and health prognostic opportunities, research efforts have explored the applicability of these devices to control workers' wellbeing levels during occupational activities. A systematic review is proposed to summarise up-to-date progress in applying physiological monitoring systems for occupational groups. Adhering with the PRISMA Statement, five databases were searched from 2014 to 2021, and 12 keywords were combined, concluding with the selection of 38 articles. Sources of risk of bias were assessed regarding randomisation procedures, selective outcome reporting and generalisability of results. Assessment procedures involving non-invasive methods applied with health and safety-related goals were filtered. Working-age participants from homogeneous occupational groups were selected, with these groups primarily including firefighters and construction workers. Research objectives were mainly directed to assess heat stress and physiological workload demands. Heart rate related variables, thermal responses and motion tracking through accelerometry were the most common approaches. Overall, wearable sensors proved to be valid tools for assessing physiological status in working environments. Future research should focus on conducting sensor fusion assessments, engaging wearables in real-time evaluation methods and giving continuous feedback to workers and practitioners.

Preventing and Monitoring Work-Related Diseases in Firefighters: A Literature Review on Sensor-Based Systems and Future Perspectives in Robotic Devices

In recent years, the necessity to prevent work-related diseases has led to the use of sensor-based systems to measure important features during working activities. This topic achieved great popularity especially in hazardous and demanding activities such as those required of firefighters. Among feasible sensor systems, wearable sensors revealed their advantages in terms of possibility to conduct measures in real conditions and without influencing the movements of workers. In addition, the advent of robotics can be also exploited in order to reduce work-related disorders. The present literature review aims at providing an overview of sensor-based systems used to monitor physiological and physical parameters in firefighters during real activities, as well as to offer ideas for understanding the potentialities of exoskeletons and assistive devices.

The effect of personal protective equipment on thermal stress: An experimental study on firefighters

BACKGROUND

Various parameters can affect the performance of firefighters. Thermal stress in firefighters is one of the most important harmful factors, which causes impaired performance and subsequent occupational accidents. Therefore, this study aimed to evaluate the effect of personal protective equipment (PPE) on thermal stress in firefighters.

MATERIALS AND METHODS

This descriptive-analytical cross-sectional study was performed on 30 firefighters. Heart rate, metabolism and temperature parameters were measured with and without using PPE in a simulated standard chamber. Then, the two indices of predicted mean vote (PMV) and predicted percentage dissatisfied (PPD) were calculated. Data analysis was performed using SPSS version 22.0.

RESULTS

The results showed that PPE-induced weight directly increased heart rate and indirectly led to an increase in metabolism and temperature as well as significant changes in PMV and PPD indices (p < 0.001). In addition, our results showed that the effect of thermal resistance of clothing (Clo) on PMV and PPD indices was very high (p < 0.001).

CONCLUSION

The findings of the study indicated that heat stress in firefighters is influenced by PPE weight and thermal resistance of clothing. Therefore, cooling vests can be used to reduce the thermal stress induced by temperature rise resulted from metabolism, PPE weight and thermal resistance of clothing. Reduced thermal stress will lead to the cooling of body temperature to acceptable levels of PMV and PPD.

Fundamental Concepts of Human Thermoregulation and Adaptation to Heat: A Review in the Context of Global Warming

The international community has recognized global warming as an impending catastrophe that poses significant threat to life on earth. In response, the signatories of the Paris Agreement (2015) have committed to limit the increase in global mean temperature to < 1.5 °C from pre-industry period, which is defined as 1950-1890. Considering that the protection of human life is a central focus in the Paris Agreement, the naturally endowed properties of the human body to protect itself from environmental extremes should form the core of an integrated and multifaceted solution against global warming. Scholars believe that heat and thermoregulation played important roles in the evolution of life and continue to be a central mechanism that allows humans to explore, labor and live in extreme conditions. However, the international effort against global warming has focused primarily on protecting the environment and on the reduction of greenhouse gases by changing human behavior, industrial practices and government policies, with limited consideration given to the nature and design of the human thermoregulatory system. Global warming is projected to challenge the limits of human thermoregulation, which can be enhanced by complementing innate human thermo-plasticity with the appropriate behavioral changes and technological innovations. Therefore, the primary aim of this review is to discuss the fundamental concepts and physiology of human thermoregulation as the underlying bases for human adaptation to global warming. Potential strategies to extend human tolerance against environmental heat through behavioral adaptations and technological innovations will also be discussed. An important behavioral adaptation postulated by this review is that sleep/wake cycles would gravitate towards a sub-nocturnal pattern, especially for outdoor activities, to avoid the heat in the day. Technologically, the current concept of air conditioning the space in the room would likely steer towards the concept of targeted body surface cooling. The current review was conducted using materials that were derived from PubMed search engine and the personal library of the author. The PubMed search was conducted using combinations of keywords that are related to the theme and topics in the respective sections of the review. The final set of articles selected were considered "state of the art," based on their contributions to the strength of scientific evidence and novelty in the domain knowledge on human thermoregulation and global warming.

Development of Fireground Exposure Simulator (FES) Prop for PPE Testing and Evaluation

Research on the performance of personal protective equipment (PPE) for the Fire Service is challenged by the ability to repeatedly and feasibly test new designs, interventions and wear trials in realistic conditions that appropriately simulate end use environments. To support firefighter PPE research and firefighter PPE acclimation/training, a multidisciplinary team has developed a low cost, easily replicable approach for simulating conditions commonly encountered by firefighters operating on the interior of a residential structure fire. The testing enclosure can be used with either stationary mannequins or firefighters conducting typical fireground activities, providing a method to study a wide range of PPE and physiological studies as well as training activities that may support developing new technologies and standardized testing opportunities. Environmental gas concentrations and firefighters' local temperatures were measured during trials and compared to data collected from simulated fireground activities and fireground responses with good agreement.

Does simulation-based training in medical education need additional stressors? An experimental study

The increased curricular integration of simulation-based training (SBT) in medical education is accompanied by researchers' calls to examine the effectiveness of SBT. We address conflicting results regarding effects of an added stressor on learning outcomes. In an experimental setting, one group of medical students (N = 20) performed cardiopulmonary resuscitation on a patient simulator. For a second group (N = 21) the scenario differed in that they encountered a defect defibrillator. We found participants of both groups to show increased biological stress-levels, independent of group allocation. Paradoxically, participants who encountered the equipment failure subjectively reported less stress. We discuss the implications of the comparable high stress levels in both groups with regards to future studies. We further discuss the result regarding subjective stress levels within the framework of attribution theory. Practitioner summary: The results of our experimental study underline the need for evidence-based choices of additional stressors for the design of simulation scenarios. We describe the choice of stimuli and setting in detail to maximise practical value for the construction of simulation-based medical trainings.

Physiologic strain of SCBA confidence course training compared to circuit training and live-fire training

Firefighting is a dangerous occupation and even training carries substantial risks. Self-contained breathing apparatus confidence courses (SCBACC) are a common type of training.

PURPOSE

Compare the physiological strain of SCBACC to live-fire training (LFT) and circuit training (CT) among academy cadets.

METHODS

Cadets wore physiologic status monitors to assess heart rate (HR) and estimated core temperature (ECT) during CT, LFT, and SCBACC of similar duration (33-38 min).

RESULTS

Data from 52 cadet firefighters (28 ± 4 yrs old) were analyzed. ECT (38.6 ± 0.4 vs 39.3 ± 0.7 vs. 39.3 ± 0.6ᵒC), peak HR (182.6 ± 9.1 vs. 192.7 ± 9.5 vs 195.9 ± 9.6 bpm), and age-predicted maximal HR (APMHR%; 94.6 ± 4.6 vs 99.9 ± 4.9 vs. 101.5 ± 4.8%) were significantly (p < 0.05) lower for CT than SCBACC and LFT, respectively.

CONCLUSIONS

SCBACC produced physiological strain greater than CT and similar to LFT. SCBACC resulted in sustained HR at 100% of age-predicted maximal values, a peak ECT of 39.3 °C, and should be considered as physiologically stressful as LFT.

Indices of physiological strain for firefighters of the Australian Defence Forces

High levels of exertion and physiological strain are the leading cause of fireground injuries. The Physiological Strain Index (PSI) provides a rating of strain based on body core temperature and heart rate; however, it may underestimate the strain of workers in protective clothing as skin temperature may be elevated. This study aimed to examine the relationship between the PSI and an Adaptive Physiological Strain Index (aPSI) that incorporates skin temperature, among firefighters wearing protective clothing. Nine male firefighters of the Australian Defence Force volunteered to participate. Participants conducted scenario-based activities while wearing turnout gear and breathing apparatus. Working in teams of four, participants would respond to a situation around and within a small building with several rooms that could be filled with smoke, however, no live fire was present. Heart rate, gastrointestinal temperature, and skin temperature were monitored throughout work and rehabilitation. Physiological strain was estimated via the PSI and aPSI. Absolute peak PSI and aPSI ratings were significantly different during work (PSI: 7.3 ± 1.6; aPSI 8.2 ± 2.0; p < 0.001). The aPSI produced higher ratings of physiological strain, >0.5 above PSI, progressively from a moderate level of strain (>6). The aPSI may provide a more accurate indication of a level of "maximal strain" for encapsulated workers than the original PSI, coincident with the occupational limits for body core temperature of 38.0 °C for general occupational groups, or 38.5 °C for selected and acclimatised personnel.

Effect of a Simulated Mine Rescue on Physiological Variables and Heat Strain of Mine Rescue Workers

OBJECTIVE

To describe physiological responses of mine rescuers during a simulated mine emergency.

METHODS

Body-worn monitors (n = 74) and core temperature (Tc) capsules (n = 54) assessed heart rate (HR), respiration rate (RR), energy expenditure (EE), oxygen consumption ((Equation is included in full-text article.)), Tc and skin temperature (Tskin), by team position and task. A multivariate analysis was performed with team positions, tasks, and measures as factors.

RESULTS

HRmean and HRpeak were 78.6% and 94.5%, respectively, of predicted maximum heart rate. Arduous labor tasks elicited higher HR, RR, and (Equation is included in full-text article.)than casualty care. Captains exhibited lower HRmean, HRpeak, RR, RRpeak, (Equation is included in full-text article.), Tc, and Tskin compared with other positions. Tc mean exceeded 38.6 °C (n = 14 recorded Tc >39 °C).

CONCLUSIONS

Captains' physical loading and heat stress were lowest. Nonetheless, all tasks and positions induced high physical load and heat strain.

Comparison of the effect of typical firefighting activities, live fire drills and rescue operations at height on firefighters' physiological responses and cognitive function

This study examined the impact of various types of firefighting activities on firefighters' physiological responses and cognitive function. Each firefighter was engaged in three conditions: (1) Live-fire activities (LFA), (2) Typical firefighting activities (TFA), and (3) Rescue operations at height (ROH). The effects of various types of firefighting activities on the physiological responses and cognitive function were evaluated by heart rate (HR), temporal artery temperature (TT), and the correct response (CR) on a cognitive test. The results indicated that, compared to the baseline, physiological response increased, while information processing performance decreased after the activity. Furthermore, HR and TT were significantly lower at the end of the firefighting activity in the LFA (149.33 bpm; 38.08 °C) compared with the TFA (152.22 bpm; 38.17 °C) and ROH (159.28 bpm; 38.24 °C) conditions. Also, CR was significantly higher at the end of the activity in the LFA and TFA compared with the ROH condition. The results showed that rescue at height was more intensive than the other firefighting tasks in decreasing physiological and cognitive function capacity after the experiment. Practitioner Summary: We assumed that various types of firefighting activities would have different effects on physiological and cognitive functions during firefighting activities. The Findings suggest that rescue at height operations, performed without the use of special protective equipment, was more influential than other firefighting duties in changing firefighters' physiological and cognitive capacity. Abbreviations: CR: correct response; LFA: live-fire activities; TFA: typical firefighting activities; ROH: rescue operations at height; HR: heart rate; TT: temporal artery tempearture; PASAT: pased auditory serila addition teat; FPC: firefighting protective clothing.

Impact of SCBA size and fatigue from different firefighting work cycles on firefighter gait

Risk of slips, trips and falls in firefighters maybe influenced by the firefighter's equipment and duration of firefighting. This study examined the impact of a four self-contained breathing apparatus (SCBA) three SCBA of increasing size and a prototype design and three work cycles one bout (1B), two bouts with a five-minute break (2B) and two bouts back-to-back (BB) on gait in 30 firefighters. Five gait parameters (double support time, single support time, stride length, step width and stride velocity) were examined pre- and post-firefighting activity. The two largest SCBA resulted in longer double support times relative to the smallest SCBA. Multiple bouts of firefighting activity resulted in increased single and double support time and decreased stride length, step width and stride velocity. These results suggest that with larger SCBA or longer durations of activity, firefighters may adopt more conservative gait patterns to minimise fall risk. Practitioner Summary: The effects of four self-contained breathing apparatus (SCBA) and three work cycles on five gait parameters were examined pre- and post-firefighting activity. Both SCBA size and work cycle affected gait. The two largest SCBA resulted in longer double support times. Multiple bouts of activity resulted in more conservative gait patterns.

Effects of simulated firefighting and asymmetric load carriage on firefighter obstacle crossing performance

Slips, trips, and falls (STF) of firefighters may occur while traversing stationary obstacles. STF risk may be amplified by fatigue from firefighting and carrying an asymmetric load. Vertical and horizontal clearances of the lead (VCL, HCL) and trailing (VCT, HCT) foot and contact with a 30 cm obstacle were examined in 24 firefighters. We examined the impact on obstacle crossing performance due to three exercise protocols (treadmill walking or simulated firefighting in an environmental chamber, and simulated firefighting in a live-fire burn building) and carrying a hose load on the right shoulder. Post-activity fatigue resulted in significant decreases in HCL and VCT. Adding a hose load did not affect choice of lead/trailing foot, but did significantly decreased HCL and increased VCL. The hose load amplified acute fatigue effects by causing a sharper decrease in both VCL and VCT. Clearances were significantly impacted by interaction effects of exercise protocol type and acute fatigue. HCL decreased and VCL remained consistent following both simulated firefighting tasks, but HCL remained unchanged and VCL increased following the treadmill protocol. Contact errors increased with fatigue and load, and more errors occurred following simulated firefighting task protocols compared to treadmill walking. Our findings suggest that both acute fatigue and carrying an additional load can cause decrements in firefighter movement, which may place a firefighter at greater STF risk. Simulated firefighting testing protocols may have greater impact on movement performance than treadmill walking. Knowledge of these results may assist in the development of a reliable, laboratory based, and standardizable simulated firefighting exercise protocol.

Assessing gait changes in firefighters after firefighting activities and while carrying asymmetric loads

One of the most common causes of injuries among firefighters is slips, trips, and falls on the fireground. Acute fatigue from firefighting activities and/or carrying asymmetric loads might impact gait characteristics increasing slip, trip, and fall risk. The purpose of this study was to examine the effects of fatigue from simulated firefighting activities and carrying asymmetric loads (fire hose over one shoulder) on firefighters' gait behavior. Both firefighting activities and asymmetric hoseload carriage led to shorter step lengths, stride lengths, single leg support time, and longer double leg support time, suggesting firefighters adopted cautious gait strategies. Simulated firefighting activities performed in either a live-fire training tower or laboratory-based environmental chamber using a firefighting activity simulator resulted in nearly identical effects on gait kinematics. This result suggests that gait assessment in a laboratory-based environmental chamber can be used as effective simulations in place of specialized burn facilities.

Impact of SCBA size and firefighting work cycle on firefighter functional balance

Slips, trips and falls are leading causes of fireground injuries. A functional balance test (FBT) was used to investigate the effects of self-contained breathing apparatus (SCBA) size and design, plus firefighting work cycle. During the FBT, subjects walked along a narrow platform and turned in defined spaces, with and without an overhead obstacle. Thirty firefighters wore three varying-sized standard SCBAs and a low-profile prototype SCBA during three simulated firefighting work/rest cycles. Firefighters were tested pre- and post-firefighting activity (one bout, two bouts with a 5-min break, or back-to-back bouts with no break). Subjects committed more errors and required longer completion times with larger SCBAs. Use of the prototype SCBA lead to lower times and fewer errors. Performing a second bout of firefighting increased completion time. Firefighters need to consider how SCBA and amount of physical activity on the fireground may influence balance in order to reduce the risk of injury.

Physiological response to firefighting activities of various work cycles using extended duration and prototype SCBA

Firefighters' self-contained breathing apparatus (SCBA) protects the respiratory system during firefighting but increases the physiological burden. Extended duration SCBA (>30 min) have increased air supply, potentially increasing the duration of firefighting work cycles. To examine the effects of SCBA configuration and work cycle (length and rest), 30 firefighters completed seven trials using different SCBA and one or two bouts of simulated firefighting following work cycles common in the United States. Heart rate, core temperature, oxygen consumption, work output and self-reported perceptions were recorded during all activities. Varying SCBA resulted in few differences in these parameters. However, during a second bout, work output significantly declined while heart rates and core temperatures were elevated relative to a single bout. Thirty seven per cent of the subjects were unable to complete the second bout in at least one of the two-bout conditions. These firefighters had lower fitness and higher body mass than those who completed all assigned tasks. Practitioner Summary: The effects of extended duration SCBA and work/rest cycles on physiological parameters and work output have not been examined. Cylinder size had minimal effects, but extended work cycles with no rest resulted in increased physiological strain and decreased work output. This effect was more pronounced in firefighters with lower fitness.

Firefighter exercise protocols conducted in an environmental chamber: developing a laboratory-based simulated firefighting protocol

A standard exercise protocol that allows comparisons across various ergonomic studies would be of great value for researchers investigating the physical and physiological strains of firefighting and possible interventions for reducing the demands. We compared the pattern of cardiorespiratory changes from 21 firefighters during simulated firefighting activities using a newly developed firefighting activity station (FAS) and treadmill walking both performed within an identical laboratory setting. Data on cardiorespiratory parameters and core temperature were collected continuously using a portable metabolic unit and a wireless ingestible temperature probe. Repeated measures ANOVA indicated distinct patterns of change in cardiorespiratory parameters and heart rate between conditions. The pattern consisted of alternating periods of peaks and nadirs in the FAS that were qualitatively and quantitatively similar to live fire activities, whereas the same parameters increased logarithmically in the treadmill condition. Core temperature increased in a similarly for both conditions, although more rapidly in the FAS. Practitioner Summary: The firefighting activity station (FAS) yields a pattern of cardiorespiratory responses qualitatively and quantitatively similar to live fire activities, significantly different than treadmill walking. The FAS can be performed in a laboratory/clinic, providing a potentially standardised protocol for testing interventions to improve health and safety and conducting return to duty decisions.