Effect of firefighters' personal protective equipment on gait

Determination of dynamic air gap thickness and analysis of its relationship with firefighters' joint movement

Objectives. The purpose of this study was to calculate the dynamic air gap thickness between the human body and the turnout gear. Relationships between the air gap thickness and joint range of motion (ROM) were also explored. Methods. The air gap thickness and joint ROM of 12 male firefighters walking in a control condition with no self-contained breathing apparatus (SCBA) and three varying-strapped SCBAs were measured using three-dimensional (3D) body scanning and 3D inertial motion capture. The interpolation technique was employed to predict the air gap thickness curve during walking. The dynamic air gap thickness was compared with the joint ROM to see how they relate to the location and percentage of movement restriction. Results. During the walking, the air gap fluctuated as a sine curve. Carrying SCBA reduced the air gap thickness at the trunk most (F = 11.17, p < 0.001, η2 = 0.63), and adjusting the shoulder strap length altered the air gap distribution at the trunk. The reduced air gap at the pelvis caused an incremental restriction on pelvis rotation. Conclusions. A compatibility design of the shoulder strap and hip belt in SCBA with the turnout jacket is suggested.

The effect of auto-generated corrective exercise programming on movement literacy among firefighters: a pilot study

INTRODUCTION

Approximately 50% of firefighter injuries occur in the musculoskeletal system. Poor movement quality increases injury risk, while movement-based interventions may reduce injuries.

PURPOSE

Investigate the effectiveness of auto-generated exercise programming on movement literacy scores among firefighters with lower baseline Functional Movement System (FMS™) scores.

METHODS

Eleven male firefighters (mean age 44) with FMS™ scores less than 14/21 were included. Detailed explanations of the seven movement screens, five clearing procedures, and scoring were provided prior to baseline FMS™ assessments. Firefighters attempted each test up to three times, with highest scores retained. Scores ranged from 0 to 3 for each of the seven movement screens, with a maximum composite score of 21. Completed test scores were reviewed, and a report was provided to each firefighter through the FMS™PRO App. Additionally, auto-generated programs from the FMS™PRO App with exercise figures, descriptions, and videos to be performed prior to routine conditioning programs were provided. On average, participants were followed up after 262 days for a re-assessment.

RESULTS

Mean composite scores significantly improved (p = .003) from 11.2 to 15.6/21, with a large effect size (r = 0.9). Individual item scores significantly improved for the deep overhead squat, hurdle, shoulder mobility, and rotary stability (p ≤ .046), with effect sizes of r = 0.3-0.8. Significant changes were not present for the inline lunge, active straight leg raise, and trunk stability push-up (p ≥ .083).

CONCLUSION

An auto-generated corrective exercise program individualized to scores on the FMS™ was effective and exceeded error thresholds based on a minimal detectable change of 2.5/21.

Fit of fire boots: exploring internal morphology using computed tomography

Fit of fire boots is a crucial factor in the safety and performance of firefighters on the hostile fireground. Firefighters have reported that ill-fitting fire boots restrict their lower body movement and sometimes cause very dangerous situations by falling off behind the wearer. By using computed tomography, this study demonstrates the potential to quantify and visualize the fit of fire boots, which previously relied on subjective feedback from the wearers. The high-resolution three-dimensional (3D) models of two fire boot products allowed a detailed observation and measurement of the internal space of the boots. Also, the boot's internal dimension was compared to the foot measurement of local firefighters, showing the significant differences between the two boots. Lastly, simulation wrapping the 3D scanned foot with the boot revealed large void spaces around the toe box and ankle, as well as the narrower ball width of the boot than the foot.

Biomechanical characterization of firefighters running under different rescue tasks

The biomechanical characteristics of runs in firefighters with different rescue tasks are unclear. This study aimed to explore the biomechanical characteristics of firefighters running in different rescue tasks and provide theoretical and practical references for firefighter training and occupational injury prevention. Eighteen professional healthy male firefighters were randomly selected as participants and tested running on different rescue tasks: wearing firefighting protective clothing (FPC), FPC+carrying a gas can (20 kg, FPC+ C), and FPC+carrying a mannequin (60 kg, FPC+M). Eight Qualisys infrared cameras and an AMTI 3D force measurement platform were used for the participant's acquisition of lower limb kinematic/kinetic data. The results showed that gait velocity and stride length of the FPC+GC and FPC+ M rescue tasks were significantly decreased compared to the FPC rescue task, while the support time was significantly increased. Compared to the FPC rescue task, the FPC+GC rescue task showed significant decreases in vertical ground reaction force (vGRF), minimum ankle dorsiflexion angle, and the maximum ankle plantarflexion power. In contrast, the FPC+M rescue task demonstrated significant increases in ankle range of motion, maximum hip extension angle, minimum knee flexion angle, maximum ankle dorsiflexion angle, maximum hip extension moment, maximum knee flexion moment, maximum hip flexion power, and hip and knee stiffness while exhibiting significant decreases in minimum ankle dorsiflexion angle. Compared to the FPC+ GC rescue task, the FPC+M rescue task exhibited significant increases in the maximum hip extension angle, minimum knee flexion angle, maximum ankle dorsiflexion angle, maximum hip flexion moment, maximum hip extension moment, maximum knee flexion moment, maximum ankle plantarflexion moment, maximum hip flexion power, maximum ankle dorsiflexion power, hip stiffness, and vGRF. Conversely, it showed significant decreases in the maximum knee flexion power. In conclusion, compared to the FPC rescue task, the FPC+GC and FPC+M rescue tasks altered the firefighter's gait performance, as evidenced by decreased gait velocity and stride length and increased support time. FPC+M rescue task would increase firefighter's risk of hip and knee injuries. Therefore, we suggest firefighters increase their strength training of the trunk, hip, and knee joint muscles as part of their daily training programs under large weight load status (60 kg and above) to reduce injury risk during rescue tasks.

Posture Evaluation of Firefighters During Simulated Fire Suppression Tasks

BACKGROUND

Posture mechanics during fire suppression tasks are associated with musculoskeletal injuries in firefighters.

METHODS

This study uses the Ovako Working Posture Analyzing System (OWAS) ergonomics tool to describe and evaluate the postures of 48 firefighters during 3 simulated tasks: (a) hose drag, (b) hose pull, and (c) high-rise pack lift. Ergonomics intervention prioritizations based on the OWAS action classification (AC) scores were identified using Wilcoxon signed-rank tests. Chi-square analyses identified associations between firefighter characteristics and OWAS AC scores.

FINDINGS

The initial hose pick-up phase of each task was identified as a high priority for ergonomics intervention (OWAS AC = 4) in 45.8%, 54.2%, and 45.8% of cases for Tasks 1, 2, and 3, respectively. Lower BMI was associated with higher AC scores for the initial hose pick-up during Task 3 (likelihood ratio = 9.20, p value = .01).

CONCLUSION

The results inform ergonomics priorities for firefighter training based on the tasks analyzed. Application to Practice: This study evaluates the posture mechanics of three commonly performed firefighting tasks. The results help inform an ergonomics training intervention focused on posture mechanics during occupational activities for firefighters.

Workers' compensation injury claims among firefighters in Ohio, 2001-2017

BACKGROUND

Firefighters are at high risk for nonfatal and fatal occupational injuries. While some past research has quantified firefighter injuries using various data sources, Ohio workers' compensation injury claims data largely have not been used.

METHODS

Public and private firefighter claims, including volunteer and career firefighters, from Ohio's workers' compensation data for 2001-2017 were identified based on occupational classification codes and manual review of the occupation title and injury description. The task during injury (firefighting, patient care, training, other/unknown, etc.) was manually coded based on the injury description. Injury claim counts and proportions were described across claim type (medical-only or lost-time), worker demographics, task during injury, injury events, and principal diagnoses.

RESULTS

33,069 firefighter claims were identified and included. Most claims were medical-only (66.28%, <8 days away from work) and involved males (93.81%) aged 25-54 years (86.54%). While the task during injury could not be categorized for many narratives (45.96%), the largest percentage that could be categorized occurred during firefighting (20.48%) and patient care (17.60%). The most common injury events were overexertion involving outside sources (31.33%) and struck by objects or equipment (12.68%). The most frequent principal diagnoses were back, lower extremity, and upper extremity sprains (16.02%, 14.46%, and 11.98%, respectively).

CONCLUSIONS

This study provides a preliminary basis for the development of focused firefighter injury prevention programming and training. Obtaining denominator data, enabling rate calculation, would strengthen the risk characterization. Based on the current data, prevention efforts focusing on the most frequent injury events and diagnoses may be warranted.

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.

Customized Occupational-Specific Graded Exercise Test for Structural Firefighters: An Update

OBJECTIVE

The aim of the study is to validate a customized V˙O 2max Graded Exercise Test (GXT) protocol specifically to accommodate firefighters with different cardiovascular fitness levels.

METHODS

Career male firefighters (N = 15) completed 3 customized GXTs on a treadmill: 1 in athletic clothes and 2 in their bunker gear to determine maximal oxygen uptake (V˙O 2max ).

RESULTS

The on-duty task protocol was reliable, V˙O 2max values of 40.2 ± 4.6 mL·kg·min -1 and 40.3 ± 5.3 mL·kg·min -1 between trials yielded an interclass correlation of 0.911 with a typical error of 1.48 mL·kg·min -1 and a coefficient of variation of 4.0%. The validity analysis indicated consistent maximal V˙O 2 values for the GXTs yielding mean interclass correlation of 0.94 with typical error of 1.16 mL·kg·min -1 and a coefficient of variation of 2.9%.

CONCLUSIONS

The customized GXT for structural firefighters has shown to be a reliable, valid, and applicable method of testing cardiovascular fitness in firefighters.

The Impact of Footwear on Occupational Task Performance and Musculoskeletal Injury Risk: A Scoping Review to Inform Tactical Footwear

The aim of this scoping review was to investigate the impact of footwear on worker physical task performance and injury risk. The review was guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews protocol and registered in the Open Science Framework. Key search terms were entered into five academic databases. Following a dedicated screening process and critical appraisal, data from the final articles informing this review were extracted, tabulated, and synthesised. Of 19,614 identified articles, 50 articles informed this review. Representing 16 countries, the most common populations investigated were military and firefighter populations, but a wide range of general occupations (e.g., shipping, mining, hairdressing, and healthcare workers) were represented. Footwear types included work safety boots/shoes (e.g., industrial, gumboots, steel capped, etc.), military and firefighter boots, sports shoes (trainers, tennis, basketball, etc.) and various other types (e.g., sandals, etc.). Occupational footwear was found to impact gait and angular velocities, joint ranges of motion, posture and balance, physiological measures (like aerobic capacity, heart rates, temperatures, etc.), muscle activity, and selected occupational tasks. Occupational footwear associated with injuries included boots, conventional running shoes, shoes with inserts, harder/stiffer outsoles or thin soles, and shoes with low comfort scores-although the findings were mixed. Occupational footwear was also linked to potentially causing injuries directly (e.g., musculoskeletal injuries) as well as leading to mechanisms associated with causing injuries (like tripping and slipping).

Effects of personal protective clothing on firefighters' gait analyzed using 3D motion capture system

OBJECTIVES

The effects of personal protective clothing (PPC) on firefighters' gait were investigated to develop high-performance PPC.

METHODS

Thirteen participants participated in human trials with three types of PPC (firefighter protective clothing (FPC); semi-enclosed chemical protective clothing (CPC_semi); full-enclosed chemical protective clothing (CPC_full)) and T-shirt (CON). A 3D motion capture system was used to obtain gait parameters (step length, step width, stride frequency, gait speed, and toe-out angle) and the range of motion (ROM) of the joints (hip, knee, and ankle).

RESULTS

PPCs produced an increase in step width (23.4%, p > 0.05), but the gait speed (9.1%) and stride frequency (6.4%) decreased compared with the CON results. ROM is affected by the PPC type and joint. FPC and CPC_semi had no significant effect in terms of the ROM of the hip and knee besides the landing angle of the knee. However, CPC_full had a significant effect on the maximum extension angle of the hip and maximum flexion angle of the knee, which reached up to 27.2%.

CONCLUSION

The ROM of the firefighter's lower limbs were limited by PPC. This study offers insights into next-generation PPC design and development, as well as guidelines for training and firefighting.

Do we all walk the walk? A comparison of walking behaviors across tetrapods

A walking gait has been identified in a range of vertebrate species with different body plans, habitats, and life histories. With increased application of this broad umbrella term, it has become necessary to assess the physical characteristics, analytical approaches, definitions, and diction used to describe walks. To do this, we reviewed studies of slow speed locomotion across a range of vertebrates to refine the parameters used to define walking, evaluate analytical techniques, and propose approaches to maximize consistency across subdisciplines. We summarize nine key parameters used to characterize walking behaviors in mammals, birds, reptiles, amphibians, and fishes. After identifying consistent patterns across groups, we propose a comprehensive definition for a walking gait. A walk is a form of locomotion where the majority of the forward propulsion of the animal comes from forces generated by the appendages interacting with the ground. During a walk, an appendage must be out of phase with the opposing limb in the same girdle and there is always at least one limb acting as ground-support (no suspension phase). Additionally, walking occurs at dimensionless speeds <1 v* and the duty factor of the limbs is always >0.5. Relative to other gaits used by the same species, the stance duration of a walk is long, the cycle frequency is low, and the cycle distance is small. Unfortunately, some of these biomechanical parameters, while effectively describing walks, may also characterize other, non-walking gaits. Inconsistent methodology likely contributes to difficulties in comparing data across many groups of animals; consistent application of data collection and analytical techniques in research methodology can improve these comparisons. Finally, we note that the kinetics of quadrupedal movements are still poorly understood and much work remains to be done to understand the movements of small, exothermic tetrapods.

Firefighters' feet: Differences by sex and weight-bearing

Firefighters have reported their protective boots to be bulky and ill-fitting, which they believe restrict the lower body movement on the unpredictable fireground. This study used 3D foot scanning to compare the shape of firefighters' feet to the general population, the shape of female firefighters' feet to males, and the impact of the heavy fire gear on foot shape. The results found the foot breadth of firefighters was larger than the general population and the feet of female firefighters were slimmer than males. Furthermore, it revealed that the feet of firefighters became longer, wider, and flatter when bearing the weight of fire gear. Protective boots should be designed based on the foot shape and dimensions of the actual population, with consideration of sex differences and the impact of weight-bearing for their safety.

Weighted vests in CrossFit increase physiological stress during walking and running without changes in spatiotemporal gait parameters

This study quantified the physiological and biomechanical effects of the 20 lb (9.07 kg, males) and 14 lb (6.35 kg, females) weighted vest used in CrossFit, and whether they were predisposed to injury. Twenty subjects (10 males, 10 females) undertook walking (0%, 5% and 10% gradient) and running trials in two randomised study visits (weighted vest/no weighted vest). Physiological demand during walking was increased with the vest at 10% but not 5% or 0% with no change in gait variables. In the running trial, the weighted vest increased oxygen uptake (males; females) (+0.22L/min, p < 0.01; +0.07 L/min, p < 0.05), heart rate (+11bpm, p < 0.01; +11bpm, p < 0.05), carbohydrate oxidation (+0.6 g/min, p < 0.001; +0.2 g/min, p < 0.01), and energy expenditure (+3.8 kJ/min, p < 0.001; +1.5 kJ/min, p < 0.05) whilst blood lactate was increased only in males (+0.6 mmol/L, p < 0.05). There was no change in stride length or frequency. Weighted vest training increases physiological stress and carbohydrate oxidation without affecting measured gait parameters. Practitioner summary: We examined the effect of weighted vest training prescribed in CrossFit (20 lb/9.07 kg, males and 14 lb/6.35 kg, females) in a randomised controlled trial. We found that physiological stress is increased in both sexes, although three-fold greater in males, but with no change in biomechanical gait that predisposes to lower-limb injury.

Exploring the comfort of head personal protective equipment for Chinese firefighters: An interview study

Head personal protective equipment (HPPE), such as helmets and masks, are protective equipment worn by firefighters to protect their head, neck, and face when they are performing tasks. As a wearable device, HPPE significantly affects firefighters' occupational safety and health along with job performance. This study aims to explore the influential factors of HPPE comfort and collect corresponding functional requirements. A semi-structured interview was conducted among 5 focus groups comprising 31 Chinese firefighters. Through a qualitative analysis of the interview results, eight dimensions of HPPE comfort were proposed: perceived change, movement, attachment, harm, emotion, anxiety, thermal comfort, and comfort of vision and hearing. The aspects of weight and size matching are the important reasons behind the comfort problems of the current HPPE. Four aspects of functional requirements were summarized: communication tools, goggles, full-face helmets, and lighting. The study findings will provide references for improving HPPE design.

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 impact of emergency responder musculoskeletal injuries in the State of Ohio

BACKGROUND

Emergency personnel operate in environments that put them at higher risk of injury to the musculoskeletal system. These injuries result in lost workdays, medical costs, and decreased productivity, all which impact emergency response systems.

OBJECTIVE

This study serves to assess the causes, costs, and disability of common work-related musculoskeletal injuries within the police, emergency medical service (EMS) workers, and firefighters of Ohio based on data from the OBWC (Ohio Bureau of Workers' Compensation).

METHODS

Our dataset included all OBWC injury claims involving a shoulder, low back, or knee from 2010 through 2014. Police and Firefighter leaders were analyzed separately from those not in a leadership role, and workers with combined Firefighter/EMS roles were analyzed separately from "pure" Firefighters and EMS personnel. Data were organized through univariate analysis of variance with post-hoc Tukey tests and analyzed based on the job of the individual and whether the individual was in a leadership role.

RESULTS

Police Officers had the highest number of total injuries in the dataset, followed by Firefighters and Firefighters/EMS workers. Police Officers and Firefighters injured their back and knees more often than their shoulders, while EMS workers injured their backs and shoulders more often than their knees.

CONCLUSIONS

The mechanisms through which injuries occur are also dependent on the job. Police officers experienced a higher percentage of motor vehicle related back problems, while firefighters had a higher percentage of injuries from overexertion. Musculoskeletal injury claims in these emergency personnel resulted in opioid prescriptions approximately 10%of the time.

Effect of structural turnout suit fit on female versus male firefighter range of motion

The purpose of this study was to assess the impact of fit on female versus male firefighter range of motion (ROM) when donning a structural turnout ensemble. Three test ensembles were evaluated: base layers (BL), turnout suit (TS), and turnout ensemble (TE). Sixteen career firefighters (10 males; 6 females) completed a user needs survey on fit and mobility restrictions, were measured in a three-dimensional body scanner, performed a static ROM protocol, and recorded ease of movement and comfort perceptions for each ensemble. Average body measurements and absolute ROM values were calculated for each test ensemble and analyzed by gender. Results demonstrated multiple significant differences in body measurements between male and female firefighters when wearing the BL and TS test ensembles. Mobility was significantly reduced when donning the TS and TE, regardless of gender. Significant differences in trunk and shoulder flexion when wearing turnout suits were identified according to participant gender.

Impact of Various Clothing Variations on Firefighter Mobility: A Pilot Study

Firefighter clothing is known to restrict movement and increase the risk of musculoskeletal injury. The aim of this study was to investigate differences between clothing variations and firefighter mobility. Data were collected from eight firefighters using a randomized counterbalanced, repeated measures, design. Three different clothing variants (V1–V3) in addition to current station wear (S) were trialed. Combinations of S and V1 (SV1) and V2 (SV2) were also trialed. Outcome measures included: standing reach height; the Functional Movement Screen [FMS]; vertical jump; a visual analogue scale [VAS] for the FMS, vertical jump, step ups and crawl; and a mannequin sketch to mark areas of discomfort. V3 was preferred over S in all tasks and performed better both objectively (FMS and vertical jump) and subjectively (VAS scores). While V1 was typically associated with poorer performance, the impacts of V1 and V2 when compared to each other and S varied depending on the tasks performed. This variation was greater when V1 or V2 were worn with S (SV1 and SV2). Areas of discomfort across all variations was the knees, followed by the thighs. Clothing that has the least impact on, or improves, mobility (especially around the lower limbs) may help reduce firefighter injury and limit subjective discomfort.

Firefighter protective clothing and self contained breathing apparatus does not alter balance testing using a standard sensory organization test or motor control test in healthy, rested individuals

BACKGROUND

There is a high rate of injury associated with firefighting: in 2016, 21% of all fireground injuries were attributed to falls, jumps and slips. Examining factors related to balance, including experience in wearing firefighter gear, may assist in reducing injury related to falls.

OBJECTIVES

To assess the effects of wearing firefighter gear on postural balance in firefighters and non-firefighters in a rested condition.

METHODS

Each subject attended two sessions. In session 1, informed consent was obtained, a threshold audiogram was collected, and the sensory organization test (SOT) and motor control test (MCT) were administered with the subject dressed in street clothes. The second session was comprised of three different conditions with the order of testing randomized across subjects: street clothing, firefighter protective garments (coat, pants, helmet, hood) with breathing apparatus but no facemask, and firefighter protective garments with breathing apparatus and facemask. Twenty subjects participated: ten firefighters (8 males) and sex and age-matched non-firefighters (8 males) completed the study.

RESULTS

SOT scores were obtained for each sub-condition, including the overall performance score and sensory weightings. For the MCT, latency and amplitude data were obtained for the three forward and three reverse translation conditions. A significant difference was found for large forward surface translations in the MCT in firefighters.

CONCLUSION

In spite of the altered center of balance created by breathing apparatus and the altered visual cues created by the facemask, wearing firefighter gear did not substantively affect anterior-posterior postural stability or motor response to linear translation in rested, healthy individuals. Firefighters and non-firefighters performed similarly across all except one of the experimental conditions.

The effect of firefighter personal protective equipment on static and dynamic balance

Firefighters work in unpredictable conditions, necessitating the use of personal protective equipment (PPE). However, the additional weight from the PPE and self-contained breathing apparatus (SCBA) alters their centre of mass (COM), restricts movement and limits vision (face mask) contributing to a firefighters' challenge of maintaining balance. Thus, the purpose of this study was to quantify the effects of firefighter PPE on static and dynamic balance. Participants performed two sets of three functional balance tests: (1) Static Single Leg (SSL); (2) Dynamic Single Leg (DSL); (3) Limits of Stability (LOS). The balance tests were performed under one control and three randomised PPE conditions: (1) athletic clothing; (2) turnouts; (3) turnouts + SCBA; (4) turnouts + SCBA + face mask. Our study found turnouts + SCBA both with and without the face mask negatively affected dynamic balance. These findings identify factors in fall-related injuries and strategies to reduce occupational risk. Practitioner summary: Slips, trips and falls are the most common cause of injury in firefighters. Our study investigated the effects of firefighter personal protective equipment (PPE) on static and dynamic balance utilising a computerised balance instrument. We found that turnouts with a self-contained breathing apparatus (SCBA) with or without face mask negatively affected balance.

Twenty-four-hour pattern of operations-related injury occurrence and severity of off-site/on-call volunteer French firefighters

We assessed the 24-h pattern of operations-related injuries (ORI) experienced by scheduled off-site/on-call French volunteer firefighters (VFF) through analysis of an archival database. Occurrence and severity - evaluated by number of lost work days (LWD) and total medical costs (TMC) - of ORI were explored in terms of risk ratios, respectively, number of ORI/number of service operations (RR_ORI), number of LWD/number of ORI (RS_LWD,) and TMC/number of ORI (RS_TMC). Additionally, the collective work performance of all involved VFF was measured in terms of the lag time (LT) between emergency call-center firefighter-answered communication for service of observer-presumed out-of-hospital cardiac arrest (OHCA) and departure of vehicle from fire station to render aid, designated LT_OHCA. Cosinor and cross-correlation statistical methods were applied. A total of 252 ORI occurred while performing 146,479 service operations. High-amplitude 24 h variation was detected in RR_ORI (p < .003), SR_LWD (p < .001), SR_TMC (p < .012), and LT_OHCA (p < .001), all with nocturnal peak time. Coherence was found between the day/night variation of LT_OHCA and RR_ORI (r = 0.7, p < .0002), SR_LWD (r = 0.5, p < .02), and SR_TMC (r = 0.4, p < .05). This investigation verifies the occurrence and severity of ORI of scheduled off-site/on-call VFF exhibit high-amplitude 24 h patterning with nocturnal excess that closely coincides with their day/night work performance measured by LT_OHCA. These findings, which are essentially identical to ones of a previous study entailing on-site/on-call career firefighters, indicate the need for fatigue management and ORI prevention programs not yet available to VFF, who compose the majority of the field service workforce of French fire departments. Abbreviations:FF: firefighters; CFF: career firefighters; VFF: volunteer firefighters; FD: fire department; LT_OHCA: lag time (LT) response in min:sec between fire department call-center-answered communication for service of presumed out-of-hospital cardiac arrest (OHCA) and departure from fire station of vehicle to render aid; LWD: lost work days; ORI: operations-related injuries; SR_LWD: severity ratio of operations-related injuries in terms of number of lost work days, calculated as number of lost work days/number of operations-related injuries; RR_ORI: risk ratio of operations-related injuries calculated as number of operations-related injuries/number of operations; SR_TMC: severity ratio of operations-related injuries in terms of total medical costs, calculated as total medical costs/number of operations-related injuries; TMC: total medical costs.

Adding body load modifies the vibratory sensation of the foot sole and affects the postural control

BACKGROUND

Heavy backpacks are often used by soldiers and firefighters. Weight carrying could reduce the speed and efficiency in task completion by altering the foot sole sensitivity and postural control.

METHODS

In fifteen healthy subjects, we measured the changes in sensitivity to vibrations applied to the foot sole when standing upright or walking after load carrying (30% body weight). The participants were asked to judge different vibration amplitudes applied on the 2nd or 5th metatarsal head and the heel at two frequencies (25 and 150 Hz) to determine the vibration threshold and the global perceptual representation (Ѱ)of the vibration amplitude (Ф) given by the Stevens power function (Ѱ = k × Фn). Any increase in negative k value indicated a reduction in sensitivity to the lowest loads. Pedobarographic measurements, with computation of the center of pressure (COP) and its deviations, were performed during weight carrying.

RESULTS

The 25-Hz vibration threshold significantly increased after weight carrying when standing upright or walking. After standing with the added loads, the absolute negative k value increased for the 25 Hz frequency. After walking with the added loads, the k coefficient increased for the two vibration frequencies. Weight carrying significantly increased both the CoP surface and CoP lateral deviation.

CONCLUSIONS

Our data show that weight carrying reduces the sensory pathways from the foot sole and accentuates the center of pressure deviations.

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.

Relationship between novel design modifications and heat stress relief in structural firefighters' protective clothing

The purpose of this study was to investigate design modifications in structural firefighter turnout suits for their ability to reduce heat stress during firefighting activities. A secondary aim of this research established a benchmark for the manikin heat loss value necessary to achieve significant improvements in physiological comfort. Eight professional firefighters participated in five simulated exercise sessions wearing a control turnout suit and one of four turnout prototypes: Single Layer, Vented, Stretch, and Revolutionary. Physiological responses (internal core body temperature, skin temperature, physiological strain, heart rate, and sweat loss) were measured when wearing each turnout suit prototype. Results demonstrated a significant increase in work time and significant reductions in heat stress (core temperature, skin temperature, and physiological strain) when participants wore the Single Layer, Vented, and Revolutionary prototypes. An estimated garment heat loss value of 150 W/m² was determined in order to achieve a significant reduction in heat stress.

Ankle restrictive firefighting boots alter the lumbar biomechanics during landing tasks

Firefighters incur high incidences of lower back and body injuries. Firefighting boots, with specific design requirements, have been shown to reduce ankle range of motion. This reduction has been associated with impaired force dissipation and lower body kinematic alterations. Thus, the aim of this study was to determine the relationship between firefighting boots, lumbar biomechanics and load carriage during landing. Our data indicates that when wearing firefighting boots, lumbar forces increased and kinematics changed in frontal and transverse planes. These changes may be occurring due to the restrictive shaft of the firefighting boot reducing ankle range of motion. Comparisons between unloaded and loaded conditions also showed increased changes in lumbar biomechanics, independent of footwear worn. Therefore, wearing firefighting boots, in addition to operational loading, may be placing firefighters at greater risk of lumbar injuries. Future research investigating firefighting boots and additional load carriage on lower body biomechanics during landing is recommended.

Additional helmet and pack loading reduce situational awareness during the establishment of marksmanship posture

The pickup of visual information is critical for controlling movement and maintaining situational awareness in dangerous situations. Altered coordination while wearing protective equipment may impact the likelihood of injury or death. This investigation examined the consequences of load magnitude and distribution on situational awareness, segmental coordination and head gaze in several protective equipment ensembles. Twelve soldiers stepped down onto force plates and were instructed to quickly and accurately identify visual information while establishing marksmanship posture in protective equipment. Time to discriminate visual information was extended when additional pack and helmet loads were added, with the small increase in helmet load having the largest effect. Greater head-leading and in-phase trunk-head coordination were found with lighter pack loads, while trunk-leading coordination increased and head gaze dynamics were more disrupted in heavier pack loads. Additional armour load in the vest had no consequences for Time to discriminate, coordination or head dynamics. This suggests that the addition of head borne load be carefully considered when integrating new technology and that up-armouring does not necessarily have negative consequences for marksmanship performance. Practitioner Summary: Understanding the trade-space between protection and reductions in task performance continue to challenge those developing personal protective equipment. These methods provide an approach that can help optimise equipment design and loading techniques by quantifying changes in task performance and the emergent coordination dynamics that underlie that performance.

A coupling system to predict the core and skin temperatures of human wearing protective clothing in hot environments

The aim of this study is to predict the core and skin temperatures of human wearing protective clothing in hot environments using the coupling system. The coupling system consisted of a sweating manikin Newton controlled by a multi-node human thermal model, and responded dynamically to the thermal environment as human body. Validation of the coupling system results was conducted by comparison with the subject tests. Five healthy men wearing protective clothing were exposed to the thermal neutral and high temperature environments. The skin temperatures of seven body segments and the rectal temperatures were recorded continuously. The predictions of core temperatures made by the coupling system showed good agreement with the experimental data, with maximum difference of 0.19 °C and RMSD of 0.12 °C. The predicted mean skin temperatures fell outside of the 95% CI for most points, whereas the difference between the simulated results and measured data was no more than 1 °C which is acceptable. The coupling system predicted the local skin temperatures reasonably with the maximum local skin temperature of 1.30 °C. The coupling system has been validated and exhibited reasonable accuracy compared with the experimental results.