Physical fitness profile of a large urban fire department: Exploring age and rank dynamics.

BACKGROUND: Firefighter physical fitness (PF) plays a crucial role in mitigating health issues and supporting occupational performance. The influence of rank on firefighter PF remains understudied and previous research is often limited by small sample sizes of firefighters volunteering for research studies, potentially biasing results towards fitter firefighters not representative of entire departments. OBJECTIVE: To examine the PF profile of firefighters in a large urban fire department and the influence of age and rank on PF. METHODS: Data, including muscular fitness, estimated aerobic capacity (VO2max), and body fat percentage (BF%) measures from 1361 firefighters (90% male; age: 37.4±10.1yrs; 60 recruits, 973 firefighters, 290 lieutenants/captains, 38 chiefs) were analyzed. Correlation and ANCOVAs were conducted to examine the impact of rank on PF while controlling for age. Score distributions were scrutinized to profile the PF of the department. RESULTS: Age was negatively associated with pull-ups (r = - 0.39), sit-ups (r = - 0.39), and push-ups (r = - 0.32), but positively associated with relative VO2max (r = 0.17) and BF% (r = 0.39). Rank had a statistically significant, but trivial effect size, on pull-ups (p = 0.028, η2 = 0.007) and sit-ups (p = 0.034, η2 = 0.005). Firefighters with lower PF levels were older, had higher BF%, lower fat-free mass, and were a greater proportion of females. CONCLUSIONS: Firefighters exhibited diverse levels of PF. Age, not rank, appeared to influence firefighters' PF. The findings that firefighters who were older, female, with poorer body composition are more likely to have lower PF levels highlights the need for individualized PF training to enhance occupational performance and health across the fire department.

Agreement of Air Bike and Treadmill Protocols to Assess Maximal Oxygen Uptake: An Exploratory Study.

Maximal oxygen consumption (V̇O2max) is an important measure of aerobic fitness, with applications in evaluating fitness, designing training programs, and assessing overall health. While treadmill assessments are considered the gold standard, airbikes (ABs) are increasingly popular exercise machines. However, limited research exists on AB-based V̇O2max assessments, particularly regarding agreement with treadmill graded exercise tests. To address this gap, a randomized crossover study was conducted, involving 15 healthy adults (9M, 6F, 7 familiar with AB) aged 30.1 ± 8.6 years. Paired t-tests, intraclass correlation coefficients (ICC), Bland-Altman and Principal component (PC) analyses were used to assess agreement between protocols. The results demonstrated good to excellent agreement in V̇O2max, maximum heart rate (HR), and rating of perceived exertion (ICC range: 0.89-0.92). However, significant differences were observed in several measures, including V̇O2max and maximum HR (p < 0.01). Overall a systematic bias 3.31 mL/kg/min (treadmill > AB, 95%CI[1.67,4.94]) was observed, no proportional bias was present; however, regular AB users (systematic bias: 1.27 (95%CI[0.20,2.34]) mL/kg/min) exhibited higher agreement in V̇O2max measures compared to non-regular users (systematic bias: 5.09 (95%CI[3.69,6.49]) mL/kg/min). There were no significant differences in cardiorespiratory coordination, between the AB and the treadmill. These findings suggest that for individuals familiar with the AB, it can be a suitable alternative for assessing V̇O2max compared to the treadmill. Future research with larger samples should focus on developing prediction equations for field AB tests to predict V̇O2max. Practitioners should consider using the AB to assess V̇O2max in individuals who prefer it over running.

Addressing challenges for repairing adult spinal cord with insights from neonates.

Stem cell therapy has emerged as a promising area of scientific investigation, sparking considerable interest, especially in spinal cord injury (SCI). Sun et al.1 discover that the extracellular matrix (ECM) from the neonatal spinal cord transmits biochemical signals to endogenous axons, thus promoting axonal regeneration.

XA21-mediated resistance to Xanthomonas oryzae pv. oryzae is dose dependent.

The rice receptor kinase XA21 confers broad-spectrum resistance to Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of rice bacterial blight disease. To investigate the relationship between the expression level of XA21 and resulting resistance, we generated independent HA-XA21 transgenic rice lines accumulating the XA21 immune receptor fused with an HA epitope tag. Whole-genome sequence analysis identified the T-DNA insertion sites in sixteen independent T0 events. Through quantification of the HA-XA21 protein and assessment of the resistance to Xoo strain PXO99 in six independent transgenic lines, we observed that XA21-mediated resistance is dose dependent. In contrast, based on the four agronomic traits quantified in these experiments, yield is unlikely to be affected by the expression level of HA-XA21. These findings extend our knowledge of XA21-mediated defense and contribute to the growing number of well-defined genomic landing pads in the rice genome that can be targeted for gene insertion without compromising yield.

Army Combat Fitness Test Scores Moderate Cognitive Function Improvements After a Ruck March: A Hierarchical Linear Model Approach.

ABSTRACT: Sax van der Weyden, M, Merrigan, JJ, Newman, K, Hahn, J, and Martin, J. Army Combat Fitness Test scores moderate cognitive function improvements after a ruck march: A hierarchical linear model approach. J Strength Cond Res 38(7): 1314-1320, 2024-Heavy load carriage is a common task for military personnel and can lead to undue physical and mental fatigue. The purpose of this study was to assess effects of load carriage on cognitive function (CF) and the role individual characteristics play in CF responses. Anthropometrics/body composition, demographics, and Army Combat Fitness Test (ACFT) scores were gathered from 47 Reserve Officers' Training Corps cadets. Cadets' CF was assessed through the concentration task grid (CTG) before (preruck), immediately after (postruck), and 3 weeks after (follow-up) a 16.09- to 19.31-km ruck march. Hierarchical linear modeling was used, with α < 0.05. The final model revealed growth, or improvement, in CF from preruck to postruck with growth decelerating, but still improved, at follow-up. The load carriage bout improved CF in most cadets, with average growth from 5.67- to 7.20-grid squares found. However, postruck CF did not return to the same level as a controlled follow-up (9.69). Sex (2.46, female), familiarity with the CTG (1.99), ACFT total scores (0.009), and relative ruck mass (-0.09) were all significant predictors of postruck CF. Army Combat Fitness Test scores (0.008) were also significant predictors of the slope between preruck and postruck, such that an ACFT score 59 points above average would result in a 1-grid square greater improvement in CF postruck. The significance of ACFT scores, lower relative ruck mass, and familiarization highlights the importance physical and mental preparation for desirable CF outcomes after occupational tasks.

Effects of implementing a mandatory and consequential annual fitness assessment in a fire department over the initial 4-year period.

BACKGROUND: Despite the physical nature of the occupation many firefighters have low levels of physical fitness which is associated with poor performance of occupational tasks and increased injury rates. For many fire departments an initial step in promoting health and wellness within the department is to conduct annual fitness testing. OBJECTIVE: To examine the effects of implementing a consequential fitness assessment within a fire department. METHODS: A retrospective repeated measures design was used to analyze annual fitness assessment data of professional firefighters (n = 1415) from 2019 to 2022 within a large urban fire department located in the mid-Atlantic region of the United States. The fitness tests included assessments of pull-ups, push-ups, sit-ups, aerobic capacity, and body composition. Repeated measure analyses of variances (ANOVAs) assessed the effect of year and a 2-way ANOVA was conducted to investigate the effects of sex and age on fitness measures on 2022 data. RESULTS: All fitness measures were found to be maintained over the 4-year period. Significant main effects of age and sex across all fitness measures, but no significant interactions were found. Older firefighters (50 + years) exhibited lower performance (p <  0.001, d >  0.80) on muscular fitness assessments than young firefighters (20-29 years). A large effect of sex (males >  females) was found for pull-ups (d = 1.04), push-ups (d = 1.23), and aerobic capacity (d = 1.38). CONCLUSIONS: The results suggest that implementing a consequential fitness assessment could help maintain firefighters' fitness levels over a multi-year period.

Flexible, scalable, high channel count stereo-electrode for recording in the human brain.

Over the past decade, stereotactically placed electrodes have become the gold standard for deep brain recording and stimulation for a wide variety of neurological and psychiatric diseases. Current electrodes, however, are limited in their spatial resolution and ability to record from small populations of neurons, let alone individual neurons. Here, we report on an innovative, customizable, monolithically integrated human-grade flexible depth electrode capable of recording from up to 128 channels and able to record at a depth of 10 cm in brain tissue. This thin, stylet-guided depth electrode is capable of recording local field potentials and single unit neuronal activity (action potentials), validated across species. This device represents an advance in manufacturing and design approaches which extends the capabilities of a mainstay technology in clinical neurology.

Association between Self-reported Sleep Quality and Single-task Gait in Young Adults: A Study Using Machine Learning.

Objective The objective of the present study was to find biomechanical correlates of single-task gait and self-reported sleep quality in a healthy, young population by replicating a recently published study. Materials and Methods Young adults ( n = 123) were recruited and were asked to complete the Pittsburgh Sleep Quality Inventory to assess sleep quality. Gait variables ( n = 53) were recorded using a wearable inertial measurement sensor system on an indoor track. The data were split into training and test sets and then different machine learning models were applied. A post-hoc analysis of covariance (ANCOVA) was used to find statistically significant differences in gait variables between good and poor sleepers. Results AdaBoost models reported the highest correlation coefficient (0.77), with Support-Vector classifiers reporting the highest accuracy (62%). The most important features associated with poor sleep quality related to pelvic tilt and gait initiation. This indicates that overall poor sleepers have decreased pelvic tilt angle changes, specifically when initiating gait coming out of turns (first step pelvic tilt angle) and demonstrate difficulty maintaining gait speed. Discussion The results of the present study indicate that when using traditional gait variables, single-task gait has poor accuracy prediction for subjective sleep quality in young adults. Although the associations in the study are not as strong as those previously reported, they do provide insight into how gait varies in individuals who report poor sleep hygiene. Future studies should use larger samples to determine whether single task-gait may help predict objective measures of sleep quality especially in a repeated measures or longitudinal or intervention framework.