Laboratory or field tests for evaluating firefighters' work capacity?

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.

Personal protective equipment impacts firefighters' anaerobic fitness

BACKGROUND

Personal protective equipment (PPE) is vital for firefighters' safety and effectiveness during daily operations. However, concerns have emerged about its potential impact on firefighters' anaerobic fitness (AF), which is crucial for their operational readiness. The Physical Ability Test (PAT) is used to assess readiness, but there is inconsistency among fire departments regarding whether PAT is conducted with full PPE or regular exercise clothing. This variation in testing conditions may exacerbate the stress on firefighters' AF.

AIMS

To analyse differences in firefighters' AF performance while wearing full PPE compared to regular exercise clothing.

METHODS

We studied two cohorts totalling 62 firefighters from specific fire departments in South Florida. We conducted occupation-specific AF tests, including handgrip dynamometry (HG), vertical jump (VJ), Margaria-Kalamen (MK), and a 300-yard shuttle run (300YD), both with full PPE (WPPE) and without PPE (NPPE). We adjusted AF variables for body weight (e.g. NPPE) and occupational weight (e.g. WPPE) and used a repeated-measures design in Jamovi (P < 0.05).

RESULTS

Wearing WPPE significantly reduced relative HG strength by 59%, VJ peak power by 11%, and MK mean power by 49%, while increased 300YD completion time by 18%.

CONCLUSIONS

The study reveals that PPE substantially impairs firefighters' anaerobic performance during occupation-specific tests. This emphasizes the need for tailored AF training programs to support the anaerobic system and related performance while wearing PPE, acknowledging the significance of occupational specificity in assessing firefighters' fitness components.

Effect of Cardiorespiratory Fitness Level on Physiological Responses and Task Performance During a High-Rise Firefighting Task

OBJECTIVES

To determine the impact of cardiorespiratory fitness (CRF) on physiological and performance outcomes during a 120-m vertical high-rise ascent in firefighters with CRF levels at or above (higher-fit) and below (lower-fit [LF]) the national recommended minimum physical employment standard (V˙O 2 max 42.3 mL·kg -1 ·min -1 ).

METHODS

Twenty-eight firefighters completed two high-rise firefighting trials (continuous and discontinuous ascent with predetermined 1-minute rest breaks). Task time, heart rate, ratings of perceived exertion, core body temperature, and thermal comfort were recorded at predetermined elevations.

RESULTS

Task time was significantly longer in both trials for the LF group. Ratings of perceived exertion and thermal comfort were also significantly higher in the LF group, with three times more LF firefighters being unable to complete the ascent without sounding their low-air alarm.

CONCLUSIONS

Higher CRF improves performance and efficiency during stair-climbing in simulated high-rise firefighting tasks.

Improving Cardiorespiratory and Muscular Function of Korean Firefighters: A Kinect-Based Mixed Reality Device Exercise Intervention Randomized Control Trial

OBJECTIVE

This study addresses declining physical fitness among Korean firefighters due to a low exercise participation rate caused by the absence of exercise instructors. The research explores Virtual Mate (VM), a Kinect-based mixed reality device, as a potential solution, but its capacity to replace training instructors in enhancing physical fitness remains uncertain.

METHODS

Twenty Korean male firefighters were divided into two groups: the exercise group received an 8-week intervention using VM, while the control group maintained regular physical activity. Cardiopulmonary function and muscle function were measured.

RESULTS

After 8 weeks, the exercise group demonstrated a significant improvement in VO 2peak . Furthermore, there were notable enhancements in the strength and endurance of most knee, shoulder, and trunk flexors and extensors.

CONCLUSIONS

Integrating VM into an exercise program can effectively improve cardiorespiratory and muscular function in Korean firefighters.

Isokinetic Shoulder Strength and its Associations to Injury in Tactical Populations: A Critical Review

The aim of this review is to evaluate existing isokinetic testing protocols for the shoulder in tactical occupations, document their shoulder strength profiles, and determine any associations to shoulder injury. Four electronic databases were searched (Medline/Pubmed, Ovid/Emcare, CINAHL/Ebsco and Embase) using the keywords police OR law enforcement, firefighter, military, AND isokinetic. Articles were eligible if they had at least one cohort of a tactical population and included isokinetic testing of the glenohumeral joint. The search yielded 275 articles. After screening for duplicates and inclusion criteria, 19 articles remained for review, six of which assessed injury correlation. 17 articles evaluated military personnel and two examined firefighters. Articles were categorized by study design, population, isokinetic protocols, strength outcome measures and statistical measures. Concentric internal rotation (IR) and external rotation (ER) strength at 60 degrees/second were reported most frequently (84% of cases). There was a paucity of testing speeds, repetition ranges and contraction types evaluated when compared to existing literature in other populations with high shoulder injury occurrence such as overhead and collision athletes. Outside of military cohorts, there is limited data available to characterise the isokinetic strength profile of the shoulder in tactical occupations. Meta-analysis for injury association was unable to be performed due to independent variable and statistical heterogeneity. However, a best evidence synthesis suggested conflicting evidence to support the association of injury with isokinetic strength testing in tactical populations. Future studies should prioritise prospective designs utilising variable speeds, repetition schemes and contraction types to better capture the dynamic occupational demands in tactical groups.

The Impact of Gloves and Occupational Tasks on Handgrip Strength in Structural Firefighters

Adequate handgrip strength (HGS) is important to safely perform fireground tasks. However, there is limited research describing the deleterious impact of glove use and fatigue from occupational tasks on HGS. Therefore, the aims of this investigation were to quantify the impact of glove use and occupational tasks on HGS, to explore the relationship between HGS versus the glove and task-induced decrement in HGS, and to evaluate the relationship between HGS and decrement in HGS versus occupational performance. Fourteen (Male: n = 13) career structural firefighters (Age: 35.5 ± 7.2 yr) performed a maximal isometric HGS assessment with and without gloves before and immediately following completion of a simulated fireground test (SFGT). General linear model with written contrast was used to identify significant differences in HGS between conditions. Pearson Correlations were used to describe bivariate relationships between the decrements in HGS and occupational task times. Significance was set at p < 0.05. There were significant main effects indicating that gloves, performing occupational tasks, and their combined effects decreased HGS (p < 0.001 for all). There were strong inverse relationships between baseline (barehanded) HGS versus the decrement in HGS from donning gloves (r = -0.82, p < 0.001) and from performing occupational tasks with gloves (r = -0.61, p = 0.021). Baseline HGS and the decrement in HGS due to wearing gloves and performing occupational tasks were not correlated to the timed completion of occupational tasks (p ≥ 0.27). These findings suggest that the use of regulation fire gloves and work-induced fatigue reduces HGS and these decrements are related to HGS. Practitioners are encouraged to utilize training strategies to optimize HGS among structural firefighters.

Body Composition Is Related to Maximal Effort Treadmill Test Time in Firefighters

Firefighting tasks may require near maximal levels of cardiorespiratory fitness. Previous research has indicated that body fat percentage (BF%) and aerobic capacity (VO_2peak) are related to the performance of firefighting tasks. Since a standard submaximal treadmill test for firefighters is terminated at 85% of maximal heart rate (MHR), key performance information relating to maximal cardiorespiratory effort may not be measured in a submaximal test. The purpose of this study was to examine the relationships between body composition and time spent running at intensities greater that 85% MHR. Height, weight, body mass index (BMI; kg/m²), BF%, MHR (bpm), VO_2peak (mL/kg/min), predicted VO_2peak (P-VO_2peak; mL/kg/min), submaximal treadmill test time (WFI_sub Test Time; min), and maximal treadmill test time (WFI_max Test Time; min) were collected in fifteen active-duty firefighters. The results indicated that significant relationships (p < 0.05) existed between BF% and VO_2peak, BF% and WFI_max Test Time, BF% and T_diff, and VO_2peak and WFI_max Test Time. P-VO_2peak was not significantly different than VO_2peak, and the WFI_max Test Time was significantly longer than the WFI_sub Test Time. These results indicate that a submaximal treadmill test may reasonably predict VO_2peak, but key information about physiological work at intensities greater than 85% MHR may be missed when using submaximal effort tests.

Fitness Policies Within the Fire Service: A Pilot Investigation of Exercise Adherence on Fitness Outcomes Among Rural Firefighters

The purpose of this study was to investigate the adherence to departmental fitness policies and to evaluate the impact of on-duty firefighters' adherence to fitness outcomes. This cross-sectional designed study utilized a convenience sample of 40 career firefighters from one department in rural southeast Georgia. Onsite gym attendance logs were recorded during a 10-month period. Firefighters were classified as lowest (0-16 sessions), low (17-30 sessions), moderate (31-44 sessions), or high (45+ sessions) adherence for analyses based on gym attendance. The fitness outcomes were retrieved from required annual fitness testing, including measurements of muscular strength (1RMest leg press and 1RMest bench press), muscular endurance (pushup), muscle power (vertical jump), cardiovascular fitness (submaximal treadmill), mobility (functional movement screen), and flexibility (shoulder elevation). Only 12.5% (n = 5) of firefighters complied with the department's fitness policy of a minimum 75% adherence rate. Furthermore, there were significant differences (P ≤ .05) between various muscular strength, endurance, and flexibility between adherence rates. This study indicated that firefighters that complied more with the fitness policies were more physically fit than those that did not. Considerations should be made to promote and enforce departmental fitness policies to ensure that firefighters can physically perform their responsibilities.

Effects of Cardiovascular Disease Risk Factors, Musculoskeletal Health, and Physical Fitness on Occupational Performance in Firefighters-A Systematic Review and Meta-Analysis

Background: Firefighting is a strenuous occupation, which necessitates that firefighters stay in good physical condition and maintain adequate cardiovascular and musculoskeletal fitness to perform their duties with minimal health and safety risks. The aim of this review is to determine the effects of cardiovascular disease risk factors, musculoskeletal health, and physical fitness on the occupational performance of firefighters. Methods: PubMed/Medline, SCOPUS, Web of Science, EBSCOHost, and ScienceDirect were searched without time-restriction. The appraisal tool for cross-sectional studies and the Critical Appraisal Skills Programme toolkit were used to conduct the methodological assessment. Data were analyzed using Review Manager 5.3, and MedCalc^® statistical software. Results: Age had a moderate effect on occupational performance (Z = 5.15, p < 0.001), whereas gender had a large effect size on occupational performance (Z = 4.24, p < 0.001). A significant moderate negative correlation was found between cardiorespiratory fitness and occupational performance (R = -0.584, p < 0.001). Significant low negative correlations were found between upper body endurance (R = -0.344, p < 0.001), abdominal endurance (R = -0.308, p < 0.001), grip strength (R = -0.421, p < 0.001), upper body strength (R = -0.318, p < 0.001), and lower body strength (R = -0.216, p = 0.020) and occupational performance. Conclusions: Aged firefighters with poor body composition and lower levels of physical fitness performed worse on all occupational performance tasks.

Evaluation of Korean Firefighters’ Fitness Using Candidate Physical Ability Test: Pilot Study

OBJECTIVES The Candidate Physical Ability Capability Test (CPAT) is a complex performance test to assess whether firefighters have sufficient ability to meet the physical demands of firefighting, and is widely used in many countries, especially in North America. In South Korea, however, simple basic physical fitness assessments are still used for firefighters’ fitness evaluation. Here, we report the physical fitness of Korean firefighters using the CPAT for the first time in Korea.METHODS Eighteen male Korean firefighters aged between 20 to 30 years participated in this study. All subjects were measured for maximum oxygen consumption (VO2max) by using gas analyzer and cycle ergometer before CPAT. On a separate day, each subject performed CPAT with the best effort. Each subject’s oxygen consumption (VO₂), heart rate (HR) and completion time were measured during the CPAT. The results of CPAT were analyzed based on VO2max and HRmax and compared to the those of previous study from North American firefighter candidates.RESULTS VO2max was significantly (p< .001) lower and HRmax was significantly (p< .05) higher in Korean firefighters (45.4±4.6 ml/kg/min and 194.2±2.1 beat/min) than American firefighter candidates (53.0±7.4 ml/kg/min and 188.0±8.0 beat/min). During CPAT, Korean firefighters showed 69.4±15.8 %VO2max and 87.6±7.8 %HRmax and American firefighter candidates had 73.1±8.0 %VO2max and 90.1±5.3 %HRmax, but these were not statistically significant. However, the completed time of CPAT was significantly slower in Korean firefighters than American firefighter candidates (726.8±84.6 sec vs. 512.0±51.0 sec, p<.001).CONCLUSIONS Korean firefighters have lower cardiorespiratory endurance capacity and CPAT performance than American firefighter candidates. In addition, Korean firefighters did not complete the CPAT within the pass time limit. It suggests that Korean firefighters need to improve more physical ability for physical demands of firefighting.

Differences in Stronger Versus Weaker Firefighters in Selected Measures of Power

Firefighters are required to perform a wide array of physically demanding job tasks, such as forcible entry, charged hose advances and victim extractions. An adequate level of muscular strength and power are required to successfully perform these tasks. The purpose of this study is to investigate the differences in stronger and weaker firefighters in measures of power. Archived data for twenty-seven (age = 34.3 ± 7.9 yr, body height = 176.3 ± 7.2 cm, body mass = 89.4 ± 15.7 kg) full-time firefighters were analyzed. Participants were placed into one of two groups [i.e., stronger (HIGH) (n = 13) and weaker (LOW) (n = 14)], based on their relative isometric mid-thigh pull (IMTPr) performance. Power measures included counter-movement jump (CMJ) height, and peak anaerobic power in watts (PAPW). Significant mean score differences were not discovered between HIGH and LOW IMTPr groups on any measures of lower-body power. Moderate positive correlations were observed between IMTP and CMJ (r = .519; p = .01). This study identified significant differences in absolute and relative strength between firefighters who were able to lift at least 2.0× their bodyweight versus those who were not. Additionally, absolute strength (as assessed by the IMTP) was significantly and positively correlated to CMJ height when compared to their weaker counterparts. These findings may provide insight into approaches for improving occupational performance and durability through the physical development of firefighters via strength and conditioning programs which focus on developing absolute strength, relative strength, and power.

Are there sex differences in physiological parameters and reaction time responses to overload in firefighters?

Male and female firefighters work side-by-side in the same in strenuous and risky conditions. Anthropometrics, physiological, and reaction time (mean of reaction time -MRT-, and errors made -E) parameters of 12 Female and 13 Male firefighters were compared. Effect of overload (step test with and without equipment) on the MRT and E were analyzed on 3 trials (T1 = 1-1s, T2 = 0.5-1s, T3 = 0.5–0.5s), compared with a pre-test condition (basal). T-test between males and females was applied to assess differences (p<0.05) in all parameters. ANOVA with repeated measures and Bonferroni on 3 conditions of step test between males and females was applied in reaction time variables. Between MRT and E, in T1, T2 and T3 trials and the 3 test conditions, ANCOVA models with interactions were used. Differences (p<0.05) in anthropometric, physiological and reaction time data emerged across groups, and on the 3rd trials (T3 vs T1 and T2) in reaction time parameters of each group. ANCOVA showed differences (p<0.001) in E among trials. Post hoc showed significant differences in T1vsT3 and T1vsT2. MRT x trial interaction was extremely significant (P<0.001). Implementing fitness and reaction time exercise programs is important to decrease the injury risk and increase work capacity in firefighters with reference to female workers.

Isokinetic Strength, Vertical Jump Performance, and Strength Differences in First Line Professional Firefighters Competing in Fire Sport

The purpose of our study was to investigate peak torque (PT) of knee extensors (KE) and knee flexors (KF), bilateral and unilateral strength asymmetries in isokinetic testing and vertical jump height (JH), vertical ground reaction force (VGRF), and force differences (_ΔVGRF) between legs during different jump tests in professional first-line firefighters (n = 15) competing in fire sports disciplines. There was a significant effect of jump type on JH (F_2,44 = 7.23, p < 0.05), VGRF (F_2,44 = 16.03, p < 0.05), and _ΔVGRF (F_2,44 = 3.45, p < 0.05). Professional firefighters achieved a mean JH of 50.17 cm in the countermovement jump free arms and high PT of KEs (3.15 Nm/kg). No significant differences (p > 0.05) and small effect sizes (d < 0.3) were found between the legs when PTs were assessed. We found a slightly higher (d = 0.53) unilateral strength ratio in non-dominant legs (58.12 ± 10.26%) compared to dominant legs (55.31 ± 7.51%). No effect of laterality was found among limb comparisons, but a higher unilateral isokinetic strength ratio was found in non-dominant legs of firefighters. A high level of strength (PT of KEs > 3 times body weight) and vertical jump performance is comparable to the performance of elite athletic populations.

What Factors Predict Upper Body Push to Pull Ratios in Professional Firefighters?

Shoulder joint injuries are common for professional firefighters. A potential cause of shoulder injury is an imbalance between anterior (push) and posterior (pull) shoulder joint musculature. Understanding what contributes to these imbalances may help to identify areas needing improvement. The purpose of this study was to investigate different push to pull (P2P) ratios and the relationships among common upper body fitness assessments, body composition, and push to pull (P2P) ratios in firefighters. Thirty-three professional firefighters completed the following testing protocol: one-repetition maximum (1RM) bench press, pull-up repetitions to failure, push-up repetitions to failure, and a body composition assessment. The endurance P2P (eP2P) was computed by dividing the number of push-up by pull-up repetitions, while strength P2P (sP2P) was the relative 1RM divided by pull-up repetitions. Bivariate relationships among variables were assessed with correlation coefficients and linear regression assessed association between eP2P and sP2P (p ≤ 0.05). The sP2P and eP2P were not associated (R 2 = 0.032, p = 0.99). Strength P2P was related with bench press 1RM (r = 0.80) and push-ups (r = 0.40). Endurance P2P was related with pull-up repetitions (r = -0.62), body fat percentage (r = 0.40), and fat mass index (r = 0.34). The results of the present study suggest sP2P and eP2P ratios should not be used interchangeably. To improve sP2P and eP2P for firefighters, it is recommended to improve the strength of anterior and posterior upper body musculature, respectively, and reduce total body fat mass.

The effect of structural firefighter protective clothing systems on single-legged functional hop test scores

BACKGROUND

Firefighters must complete a physical ability test to assess work readiness. There is a lack of understanding of how personal protective clothing (PPC) affects functional performance tests for work readiness, e.g. Triple Hop for Distance (THD) and Triple Hop for Work (THW).

OBJECTIVE

To examine firefighter PPC's effect on the THD and THW measures.

METHODS

Thirty-one healthy, untrained participants (male = 20, female = 11; age = 23±3 years; height = 175.30± 11.12 cm; mass = 77.94±14.24 kg; mass in PPC = 89.14±14.68 kg) completed three successful trials of the THD on their dominant and non-dominant leg, with and without PPC. The main outcome measures included maximum and mean distances on the THD with and without PPC and THW.

RESULTS

We identified a significant decrease in THD measures (mean difference = 97.83 cm; p <  0.001) and THW measures (mean difference = -326.61J; p <  0.001) when donning PPC in the dominant leg. We identified a significant decrease in THD (mean difference = 121.48 cm; p <  0.001) and THW (mean difference = 493.15J; p <  0.001) for females, and a significant difference for THD (mean difference = 84.83 cm; p <  0.001) for males when donning PPC.

CONCLUSIONS

The addition of PPC decreased the THD and THW measures. The additional mass of the PPC required the more energy to move the same distance without the PPC.

Analysis with applied statistics of the safety use of rope rescue equipment

This article presents the results of a questionnaire-based survey intended to contribute to the development of safety and security requirements for rescue operations involving rope technology, the relevant rescue methodology and the operations procedure. The article tackles a number of issues that highlight the relevant criteria for choosing the proper rope-technology equipment to be used. The completed questionnaires have been assessed with various statistical tests, showing which criteria should be used as requirements by the rescue teams when selecting the safest possible rope-technology equipment. The importance of the article is emphasized by the fact that it discusses a safety technology topic that is getting relatively less attention, although it is a rather important matter for rescue in emergency situations.

Physical Employment Standards for UK Firefighters: Minimum Muscular Strength and Endurance Requirements

Objective:

The aim of this study was to assess sensitivity and specificity of surrogate physical ability tests as predictors of criterion firefighting task performance and to identify corresponding minimum muscular strength and endurance standards.

Methods:

Fifty-one (26 male; 25 female) participants completed three criterion tasks (ladder lift, ladder lower, ladder extension) and three corresponding surrogate tests [one-repetition maximum (1RM) seated shoulder press; 1RM seated rope pull-down; repeated 28 kg seated rope pull-down]. Surrogate test standards were calculated that best identified individuals who passed (sensitivity; true positives) and failed (specificity; true negatives) criterion tasks.

Results:

Best sensitivity/specificity achieved were 1.00/1.00 for a 35 kg seated shoulder press, 0.79/0.92 for a 60 kg rope pull-down, and 0.83/0.93 for 23 repetitions of the 28 kg rope pull-down.

Conclusions:

These standards represent performance on surrogate tests commensurate with minimum acceptable performance of essential strength-based occupational tasks in UK firefighters.

Do police officers and firefighters have a higher risk of disease than other public officers? A 13-year nationwide cohort study in South Korea

OBJECTIVES

The work of public officers involves repeated and long-term exposure to heavy workloads, high job strain and workplace violence, all of which negatively impact physical and mental health. This study aimed to evaluate and compare the incidences of diseases among different categories of public officers in Korea, in order to further understand the health risks associated with these occupations.

DESIGN

A cohort study using the National Health Insurance data.

PARTICIPANTS

We collated claims data between 2002 and 2014 for 860 221 public officers.

PRIMARY AND SECONDARY OUTCOME MEASURES

Age-standardised rates were calculated using the direct standardisation method, and HRs were calculated using the Cox proportional hazard regression models.

RESULTS

Overall, we found that police officers and firefighters had a higher incidence of a range of diseases when compared with national and regional government officers (NRG). The most prominent HRs were observed among police officers for angina pectoris (HR: 1.52, 95% CI 1.49 to 1.54), acute myocardial infarction (HR: 1.84, 95% CI 1.77 to 1.92) and cerebrovascular disease (HR: 1.36, 95% CI 1.31 to 1.40). Firefighters were more susceptible to physical ailments and were at a significantly higher risk for traumatic stress disorders (HR: 1.40, 95% CI 1.26 to 1.56) than NRGs.

CONCLUSION

Compared withNRGs, police officers had higher HRs for all measured diseases, except for traumatic stress disorders. While firefighters had higher HRs for almost all diseases examined, public education officers had a higher HR for traumatic stress disorders, when compared with NRGs.

Grip Strength and Its Relationship to Police Recruit Task Performance and Injury Risk: A Retrospective Cohort Study

Suitable grip strength is a police occupational requirement. The aim of this study was to investigate the association between grip strength, task performance and injury risk in a police population. Retrospective data of police recruits (n = 169) who had undergone basic recruit training were provided, including handgrip strength results, occupational task performance measures (consisting of police task simulations [SIM], tactical options [TACOPS] and marksmanship assessments) and injury records. Left hand grip strength (41.91 ± 8.29 kg) measures showed a stronger correlation than right hand grip strength (42.15 ± 8.53 kg) with all outcome measures. Recruits whose grip strength scores were lower were significantly more susceptible to failing the TACOPS occupational task assessment than those with greater grip strength scores, with significant (p ≤ 0.003) weak to moderate, positive correlations found between grip strength and TACOPS performance. A significant (p < 0.0001) correlation was found between grip strength, most notably of the left hand, and marksmanship performance, with those performing better in marksmanship having higher grip strength. Left hand grip strength was significantly associated with injury risk (r = -0.181, p = 0.018) but right hand grip strength was not. A positive association exists between handgrip strength and police recruit task performance (notably TACOPS and marksmanship) with recruits who scored poorly on grip strength being at greatest risk of occupational assessment task failure.

Relationships between strength and endurance parameters and air depletion rates in professional firefighters

The aim of this study was to quantify the physical demands of a simulated firefighting circuit and to establish the relationship between job performance and endurance and strength fitness measurements. On four separate days 41 professional firefighters (39 ± 9 yr, 179.6 ± 2.3 cm, 84.4 ± 9.2 kg, BMI 26.1 ± 2.8 kg/m2) performed treadmill testing, fitness testing (strength, balance and flexibility) and a simulated firefighting exercise. The firefighting exercise included ladder climbing (20 m), treadmill walking (200 m), pulling a wire rope hoist (15 times) and crawling an orientation section (50 m). Firefighting performance during the simulated exercise was evaluated by a simple time-strain-air depletion model (TSA) taking the sum of z-transformed parameters of time to finish the exercise, strain in terms of mean heart rate, and air depletion from the breathing apparatus. Multiple regression analysis based on the TSA-model served for the identification of the physiological determinants most relevant for professional firefighting. Three main factors with great influence on firefighting performance were identified (70.1% of total explained variance): VO2peak, the time firefighter exercised below their individual ventilatory threshold and mean breathing frequency. Based on the identified main factors influencing firefighting performance we recommend a periodic preventive health screening for incumbents to monitor peak VO2 and individual ventilatory threshold.

Impact of error self-perception of aerobic capacity in the safety and efficacy of the lifeguards

INTRODUCTION

The strong physical demands that are required of lifeguards during rescues also require an accurate self-perception of one's fitness level to be able to regulate the intensity of effort.

OBJECTIVES

The aim of this study was to determine the real aerobic capacity (RAC) and to compare it with two self-reported measurements: subjective appraisal of aerobic capacity (SAAC) and appraisal of physical exercise (APE).

METHODS

Fifty-two professional lifeguards were included in the study. For an objective assessment of RAC, the lifeguards' maximum oxygen uptake (VO2max) values were measured during treadmill stress tests. A fitness assessment questionnaire was used to obtain the SAAC and APE values.

RESULTS

We found a statistically significant association between the APE and RAC variables in the contingency analysis (p < 0.001). In total, 93.7% of the lifeguards who obtained a VO2max value below 43 ml kg(-1) min(-1) considered their aerobic capacity to be high or very high.

CONCLUSION

This self-perception error of true aerobic capacity could lead to premature fatigue during a rescue, endangering both the lifeguard's life and the life of the victim. These data may help lifeguards and beach managers to become aware of the need to know lifeguards' true physical conditions through testing and structured training programs.

Multivariate statistical assessment of predictors of firefighters' muscular and aerobic work capacity

Physical capacity has previously been deemed important for firefighters physical work capacity, and aerobic fitness, muscular strength, and muscular endurance are the most frequently investigated parameters of importance. Traditionally, bivariate and multivariate linear regression statistics have been used to study relationships between physical capacities and work capacities among firefighters. An alternative way to handle datasets consisting of numerous correlated variables is to use multivariate projection analyses, such as Orthogonal Projection to Latent Structures. The first aim of the present study was to evaluate the prediction and predictive power of field and laboratory tests, respectively, on firefighters’ physical work capacity on selected work tasks. Also, to study if valid predictions could be achieved without anthropometric data. The second aim was to externally validate selected models. The third aim was to validate selected models on firefighters’ and on civilians’. A total of 38 (26 men and 12 women) + 90 (38 men and 52 women) subjects were included in the models and the external validation, respectively. The best prediction (R²) and predictive power (Q²) of Stairs, Pulling, Demolition, Terrain, and Rescue work capacities included field tests (R² = 0.73 to 0.84, Q² = 0.68 to 0.82). The best external validation was for Stairs work capacity (R² = 0.80) and worst for Demolition work capacity (R² = 0.40). In conclusion, field and laboratory tests could equally well predict physical work capacities for firefighting work tasks, and models excluding anthropometric data were valid. The predictive power was satisfactory for all included work tasks except Demolition.