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The purpose of this study was to examine the influence of inter-limb leg lean tissue mass (LTM) asymmetry on stair climb (SC) performance in firefighters. Forty-one career firefighters (age = 32.3 ± 8.2 years, body mass = 92.1 ± 18.6 kg, stature = 178.3 ± 7.9 cm) visited the laboratory on one occasion and completed a whole body and leg composition assessment followed by a timed and weighted SC task. Percent body fat (%BF) and leg LTM were determined during a DEXA scan and regional thigh analysis. Asymmetry was assessed by the percent difference between limbs (dominant limb LTM - non-dominant limb LTM)/dominant limb LTM × 100) and a ± 3% cut-off for asymmetry classification. Participants ascended and descended 26 stairs four times as quickly as possible while wearing a weighted (22 kg) vest. Point biserial correlations were used to assess the relationship of inter-limb leg LTM asymmetry and SC performance before and after controlling for age and %BF. Results indicated that inter-limb leg LTM asymmetry was associated with longer SC task time (poorer performance) both before (r = 0.432, P = 0.005) and after (r = 0.502, P = 0.001) controlling for age and %BF. Our findings indicated that inter-limb leg LTM asymmetry negatively impacts firefighter SC performance, which may be improved with appropriate exercise interventions.

This study examined the influence of leg inter-limb lean tissue mass (LTM) asymmetry on SC performance in career firefighters. We found that inter-limb leg LTM asymmetry was associated with reduced SC performance, prior to and after controlling for age and percent body fat. Interventions that mitigate these asymmetries may improve occupational performance.

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This study examined the feasibility of workload monitoring to assess internal workload in law enforcement officers (LEO) using a multi-methodological approach. Fifty front-line LEO completed workload surveys on workdays for eight weeks. Retention and adherence were assessed across the survey period. LEO completed usability and likelihood to continue questionnaires, while departmental administrators (n = 8) received workload reports and completed utility and sustainability questionnaires. A subsample of LEO and administrators participated in semi-structured interviews, following consensual qualitative research design. LEO retention (96%), survey adherence (94%), and usability scores (88.3/100) were high, with a moderate likelihood to continue to use the survey. Administration reported high utility and sustainability. The high adherence rates and usability scores, coupled with strong administrative support, suggest that workload monitoring may be a feasible strategy among LEO to monitor occupational workloads. The LEO and administration feedback highlight areas of improvement (e.g., data transparency, departmental collaboration) to inform future implementation.

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INTRODUCTION: The purpose of this study was to examine the impact of age on the affective responses (attitude, feelings, self-efficacy, intention, enjoyment, and fondness) after a worksite circuit-style resistance exercise routine in career firefighters. METHODS: Nineteen young (25.5 ± 3.3 yr) and 19 middle-aged male career firefighters (50.3 ± 3.5 yr) completed 2 d of physical testing at local fire stations. Participants were familiarized with the resistance training exercises (deadlift, shoulder press, lunge, and upright row) at visit 1 and performed a multirepetition maximum (RM) assessment to prescribe the appropriate loads for the resistance exercise bout on visit 2. The resistance training session included three sets of 8 to 10 repetitions per exercise at 80% 1-RM. Participants completed a postexercise questionnaire examining affective responses and a rating of perceived exertion (RPE). Mann-Whitney U tests and an independent t-test were used to determine differences between the young and middle-aged firefighters' affective responses and RPE, respectively. RESULTS: There were no significant differences between groups for any of the six affective responses ( P = 0.062-0.819) or RPE ( P = 0.142). CONCLUSIONS: Age did not influence the perceived effort or affective responses following an acute bout of worksite resistance exercise. Firefighters reported overall positive attitudes, feelings, and fondness paired with high self-efficacy and intention at a training frequency of twice per week. However, confidence, intention, and enjoyment decreased at higher training frequencies (i.e., 3-4x per week). Circuit-style resistance training performed twice per week may be a feasible and practical worksite exercise routine across ages in the fire service.

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PURPOSE: The purpose of this study was to examine the time course of health, fitness, and occupational performance changes in firefighter recruits across a fire academy. METHODS: Nineteen recruits (24.9 ± 4.3 yr; 26.7 ± 3.1 kg·m -2 ) had their body composition, balance, vertical jump (VJ) performance, cardiorespiratory fitness (CRF), upper and lower body strength, hamstrings-to-quadriceps (H/Q) ratio, lower back endurance, and weighted stair climb (SC) performance assessed at the beginning (week 1 [W1]), midpoint (week 15 [W15]), and end (week 30 [W30]) of a fire academy. RESULTS: The fire academy improved body composition, balance, CRF, leg extension strength, and SC performance from W1 to W15 ( P ≤ 0.042) which then plateaued at W30 ( P ≥ 0.314). Leg flexion strength and the H/Q ratio decreased from W1 to W15 ( P ≤ 0.035) and plateaued at W30 ( P ≥ 0.947). Upper body strength was similar at W1 and W15 ( P ≥ 0.999), but decreased at W30 ( P ≤ 0.033). However, no significant changes occurred across the academy for VJ performance or lower back endurance ( P ≥ 0.090). CONCLUSIONS: These findings highlight the positive effect of the academy on body composition, CRF, balance, SC performance, and leg extension strength. However, the decreases in upper body and leg flexion strength, the H/Q ratio, and lack of changes in VJ performance and low back endurance may highlight key areas of need to maximize injury prevention and performance enhancement efforts in the academy. Further, the varied time course of changes may help fire departments identify opportunities to modify exercise programming across their academies.

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Upper body (UB) strength is important for occupational tasks and injury prevention in law enforcement officers (LEOs). Portable, reliable, and cost-effective assessments are needed to examine UB strength among LEOs in field settings. The purpose of this study was to examine the test-retest reliability and minimum difference (MD) values of a novel and portable isometric upright row assessment in probation officers. Thirty certified probation officers (18 women; age = 38.9 ± 9.0 years, body mass = 98.8 ± 27.1 kg, stature = 171.4 ± 14.0 cm) volunteered for this investigation. Testing occurred on-site across two sessions (2-5 days apart). Participants stood upon an aluminum plate with a chain attached to a handle and dynamometer. They grasped the handle with a pronated grip, two cm below the umbilicus, and performed three isometric maximal voluntary contractions. Intraclass correlation coefficient (ICC2,1), standard error of the measurement (SEM), and MD values were calculated. Results indicated no significant systematic error (p = 0.080) across sessions. The ICC2,1, SEM, and MD values for UB strength were 0.984, 27.20 N (4.1% of the mean), and 75.38 N (11.3% of the mean), respectively. These data suggest this isometric upright row assessment is a reliable, portable, and cost-effective measure of UB strength to assess and monitor LEOs in field settings.

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OBJECTIVE: Although workload monitoring is commonly used in athletic settings to mitigate injury risk, we are unaware of previous studies examining its feasibility among firefighters. METHODS: Nineteen firefighter recruits completed a short online workload survey at the end of each training day (Monday-Friday) for 26 weeks during the academy. A modified System Usability Scale was provided at midtesting (3 months into the academy) and posttesting (end of the academy). RESULTS: The recruits perceived the survey to be user-friendly throughout the academy (83.6 ± 13.6). However, questions 1 (survey frequency) and 6 (survey consistency) decreased and increased from midtesting to posttesting, respectively. Adherence was overall poor, decreasing from midtesting to posttesting. CONCLUSIONS: Our findings suggest that workload monitoring is a user-friendly tool within tactical populations; however, future research should consider optimal survey frequency to enhance compliance.

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BACKGROUND: Menopausal changes coupled with age-related reductions in muscle strength can impact functionality. AIM: To evaluate the differences in muscle strength, dominant leg lean mass (DLMleg ), relative protein intake (r_PRO) and physical activity (PA) between premenopausal (PRE) and perimenopausal (PERI) women. METHODS: Twenty-four PRE- (age = 39.8 ± 3.3 years; BMI: 25.3 ± 5.0 kg/m2 ) and 24 PERI-women (age = 50.0 ± 3.3 years; BMI: 26.5 ± 5.4 kg/m2 ) participated in leg extensor isometric peak force (PF), DLMleg , r_PRO and PA. Independent samples t-tests and one-way analyses of covariance covaried for age and DLMleg were used to compare groups. RESULTS: The PRE group had significantly higher PF (mean difference ± standard error: 57.8 ± 28.0 N; p = 0.045) and DLMleg (0.7 ± 0.3 kg; p = 0.031) when compared to the PERI group. There were no significant differences in r_PRO, or PA between groups (p = 0.173-0.423). When covaried for age and DLMleg , there was no significant difference in PF (p = 0.982 and 0.405, respectively). CONCLUSIONS: Age and DLMleg may be important contributors to menopause-phase related differences in strength.

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The purpose of this study was to determine if segmental bioelectrical impedance spectroscopy characteristic frequency (fc) and phase angle (Pa) were reflective of differences in quadriceps muscle size and quality, respectively, in normal weight and obese older men, and to assess the impact of hydration status on these measurements. Forty-one healthy older men volunteered for this study and were recruited by age (65-74 years) and two body mass index groups: normal weight and obese. Participants visited the laboratory on one occasion where they underwent a hydration status assessment via urine specific gravity, a percent body fat assessment via dual-energy X-ray absorptiometry, a segmental bioelectrical impedance spectroscopy thigh assessment to determine fc and Pa, and resting ultrasonography to assess superficial quadriceps cross-sectional area and echo intensity as a proxy for muscle quality. Urine specific gravity was not different between the groups (P = 0.116); however, echo intensity, cross-sectional area, and percent body fat were greater in the obese group (P < 0.001), and both fc and Pa were greater in the normal weight group (P < 0.001). Larger muscle cross-sectional area was associated with lower fc (r = -0.597, P < 0.001), but was not associated with Pa (P = 0.469). Poorer muscle quality (higher echo intensity) was associated with lower Pa (r = -0.765, P < 0.001), but not associated with fc (P = 0.244). There was no association between fc and Pa (P = 0.449). All group differences and associations remained unchanged after controlling for urine specific gravity. Segmental bioelectrical impedance spectroscopy may offer an inexpensive, time efficient, and portable assessment of quadriceps muscle size and quality in older men.

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PURPOSE: This study examined worker characteristics and behaviors and the perceived importance of job-related tasks associated with the willingness to perform a proposed probation officer physical ability test (PROPAT). METHODS: North Carolina probation officers (N = 1213, 46.2% female, 39.8 ± 10.1 yr, 30.7 ± 6.6 kg·m-2) completed a survey including demographics, health history, and job-related tasks. A multivariable logistic regression model estimated the odds of being willing to perform the PROPAT. Adjusted odds ratios (ORadjusted) with 95% confidence intervals (CI) were calculated, with those excluding 1.00 deemed statistically significant. RESULTS: The majority (72%) of probation officers were willing to perform the PROPAT. Being male (compared with female) (ORadjusted = 1.50, 95% CI = 1.12-2.02) and having moderate (ORadjusted = 1.51, 95% CI = 1.10-2.08) and high physical activity status (ORadjusted = 2.89, 95% CI = 1.97-4.28) (compared with low) increased the odds of being willing to perform the PROPAT. Additionally, reporting a greater importance of tasks, including running to pursue a suspect (TASKRUN, 1-unit increase, ORadjusted = 1.25, 95% CI = 1.10-1.43) and dragging an unresisting person (TASKDRAG, 1-unit increase, ORadjusted = 1.16, 95% CI = 1.01-1.32), increased the odds of being willing to perform the PROPAT. Increasing age (1-yr increase, ORadjusted = 0.96, 95% CI = 0.94-0.98), class II (ORadjusted = 0.45, 95% CI = 0.28-0.71) and class III obesity (compared with normal weight, ORadjusted = 0.55, 95% CI = 0.32-0.93), and a previous musculoskeletal injury (ORadjusted = 0.57, 95% CI = 0.35-0.93) all decreased the odds of being willing to perform the PROPAT. CONCLUSIONS: These results suggest being older, previously injured, obese (body mass index ≥ 35 kg·m-2), and less active is associated with being less willing to participate in the PROPAT, whereas males and reporting a higher importance of the TASKRUN and TASKDRAG activities is associated with being more willing to participate in the PROPAT. Departments can use these findings to identify feasible strategies (e.g., education and physical training) to improve the implementation of physical employment standards.

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