Changes in Health and Physical Fitness Parameters After 6 Months of High-intensity Group Exercise in Firefighters

Cities annually budget thousands of dollars for rehabilitation services due to work-related injuries that affect firefighters. Proper training methods may be used as an effective preventative measure for many of the musculoskeletal injuries sustained as a first responder that are inherent with the profession. The physical demands of firefighting require that the individuals employed in this profession be, at minimum, in good physical condition. The traditionally low fitness levels and poor exercise habits of firefighters may predispose this population to an increased risk of chronic conditions, such as cardiovascular and metabolic disease. Purpose: The purpose of this study was to analyze changes in health and fitness parameters of professional firefighters across North Texas during a 6-month training program. Methods: Twenty-five professional firefighters (23 males and 2 females; age 37.5 ± 10.0 years; height 70.9 ± 2.7 in; weight 96.4 ± 15.7 kg; BMI 29.8 ± 7.6 kg/m2) completed 6 months of high-intensity group training, consisting of 2 training sessions per week. Exercises were chosen to mimic common activities of firefighting. These included: farmer’s walks, squats, pushups, planks, sled pushes, sled drags, rows, tire flips, sledge hammer strikes, and medicine ball slams. These individuals underwent a pre- and post-fitness testing protocol that consisted of body composition, range-of-motion, anaerobic power, muscular endurance, and cardiorespiratory fitness. A repeated-measures MANOVA was used to determine any differences between testing periods. A significance level of 0.05 was used. Results: Comparing post-testing to pre-testing values, improvements in sit-and-reach (31.8 ± 7.5 vs. 25.3 ± 6.5 cm; p \u3c 0.001), mean power (706.9 ± 125.2 vs. 660.2 ± 125.5 W; p \u3c 0.001), fatigue index (54.0 ± 8.0 vs. 60.8 ± 7.4 %; p \u3c 0.001), curl ups (48 ± 26 vs. 21 ± 15; p \u3c 0.001), pushups (35 ± 16 vs. 30 ± 15 p = 0.005), VO2max (38.2 ± 5.8 vs. 35.6 ± 4.9 ml/kg/min; p = 0.005) & energy expenditure (11.0 ± 1.5 vs. 10.1 ± 1.3 METS; p = 0.003) were found following the 6-month training program. No differences in body composition or peak power were observed (p \u3e 0.05). Conclusion: Six months of high-intensity group exercise may improve measures of physical fitness in firefighters

Divine Hiddenness and the Challenge of Inculpable Nonbelief

Divine hiddenness is the idea that God is in some sense hidden or obscure. This dissertation responds to J.L. Schellenberg\u27s argument, based on divine hiddenness and human reason, against the existence of God. Schellenberg argues that if a perfectly loving God exists, we would not expect to find such widespread nonbelief in God\u27s existence. Given the amount of reasonable nonbelief in the world, Schellenberg argues that an agnostic ought to conclude that God does not exist rather than conclude that God is hidden. Schellenberg\u27s argument has three major premises: (1) If there is a God, he is perfectly loving; (2) If a perfectly loving God exists, reasonable nonbelief does not occur; (3) Reasonable nonbelief occurs. I provide a theistic response to the argument from divine hiddenness in an attempt to offer the agnostic a reasonable reply that prevents an atheistic conclusion. In order to defeat the prima facie evidence for Schellenberg\u27s argument, I first question the amount of reasonable nonbelief in an effort to reduce the evidential force of Schellenberg\u27s third premise. This is followed by a consideration of possible defenses to challenge the second premise that if a perfectly loving God exists, reasonable nonbelief does not occur. Free-will defenses are considered, but I conclude that they are not sufficient as a response to the challenge that Schellenberg has developed. Instead, I argue that skeptical theism is a defense which can be successful in preventing an agnostic from being necessarily led, epistemically, to conclude that God does not exist. Finally, I develop a second defense motivated by concepts from Paul K. Moser that I take to be the most promising response to Schellenberg\u27s argument from divine hiddenness. By casting the evidence for God in a new context, I conclude that the challenge that Schellenberg has developed can be overcome by providing a defense which shows that God, motivated by divine love, may in some sense be hidden so as to allow reasonable nonbelief to occur at least for a time

The Relationship of Physiological and Fitness Variables to Performance in CrossFit®-based Exercise: Preliminary Findings

CrossFit® is a rapidly expanding exercise program as well as an emerging competitive sport. Little is known regarding the correlation of physical fitness measures and performance in CrossFit®-based events. PURPOSE: The purpose of this study was to determine the relationship between various physiological and fitness variables and performance in a typical CrossFit®-based workout. METHODS: Nine male participants (age = 32.2 ± 3.6 yrs; height = 173.1 ± 9.8 cm; weight = 86.1 ± 11.6 kg; BMI = 28.6 ± 1.2 kg/m2) who had performed CrossFit® as their primary exercise program at least 3 days/week for the past 12 months were recruited. Participants performed a test of maximal aerobic fitness (VO2max), a Wingate test, a DEXA scan, a 1RM Clean and Jerk, and a series of exercises that would typically be included in a CrossFit®-based workout. More specifically, participants performed 15 Wall Ball exercises (20 lbs.), 15 Box Jumps (24 in.), 10 Burpees over a barbell, and 10 Kipping Pullups. If all exercises were completed, the participants repeated the exercises in the same order. The participants were asked to stop after 12 min, and the total number of repetitions completed was recorded. Questions regarding the participants’ exercise history and dietary habits were asked. Spearman’s correlation was used to identify relationships between the variables and performance (number of repetitions completed) during the CrossFit®-based workout. Participants were also grouped into “high” (≥ median) or “low” (\u3c median) groups, and independent samples t-tests were used to compare how each group performed during the CrossFit®-based workout. Statistical significance was set at .05. RESULTS: Performance during the CrossFit®-based workout had strong, positive relationships with strength-to-body weight ratio (r = .686; p = .041), 1RM Clean and Jerk (r = .915; p = .001), and years of experience (r = .869; p = .002). Participants with higher strength-to-body weight ratios (p = .036), lower fatigue index (p = .022), lower body fat percentage (p = .022), higher weight lifted during the 1RM Clean and Jerk (p = .017), and more years of experience (p = .027) completed more repetitions during the CrossFit®-based workout. Significance was not found with any other variable. CONCLUSION: Based on these early findings, anaerobic fatigue resistance, body fat percentage, muscular power, and exercise history appear to be significant predictors of performance in CrossFit®-based workouts

The Effects of Sport Specific, Governed, and Non-Controllable Focal Point on Female Vertical Jump Performance

Graduate Applie

Effects of Lab Technician Administered vs. Subject Administered Resistance on Wingate Performance

Graduate Applie

Assessing the Relationship between Body Composition and 50-km Running Performance

Graduate Applie

Changes in Health and Physical Fitness Parameters After 6 Months of High-intensity Group Exercise in Firefighters: Preliminary Data

The physical demands of firefighting require the men and women employed in this profession to be in optimal physical condition to perform their jobs proficiently, as well as to mitigate the risk of injury. Every year, the city of Addison, TX, budgets many thousands of dollars to the compensation plan for first responders. Most of the funding is used for rehabilitation services due to work related injuries. PURPOSE: While many of these injuries are unavoidable due to the inherent risks of the profession, ensuring proper physical fitness is one of the most effective methods to reduce many of these impairments. The purpose of this preliminary study was to characterize health and fitness parameters in 18 professional firefighters from the city of Addison, TX, prior to a 6-month training program. METHODS: Upon arrival, all participants underwent testing in the following order: body composition, range of motion, anaerobic power, muscular endurance, and cardiorespiratory fitness. All participants also completed a detailed health history questionnaire and answered questions specifically addressing chronic low back pain. RESULTS: The following values were attained from testing: total body fat: 30.1±9.7%; flexibility: 24.9±6.3 cm; peak power: 1068.7±272.9 W; mean power: 636.9±143.4 W; time to peak power 0.57±0.35 sec; pushup: 28.8±14.9; curl up: 22.1±15.8; VO2max: 34.1±5.1 ml/kg/min. CONCLUSION: Based off the comparison of reported means and ACSM’s fitness norms, it can be concluded that improvements are necessary in body composition, muscular endurance, range of motion and cardiorespiratory fitness. With improvements in these physiological variables, tactical performance may be optimally performed in a safer manner

Myogenic Regulatory Factor Expression is Downregulated Following Formoterol Stimulation in Thyroid Hormone Depleted Skeletal Muscle

In skeletal muscle (SKM), gene expression of transcription factors regulating myogenesis are dependent on Thyroid Hormone (TH) signal transduction. Expression of myogenic regulatory factors may be altered due to dysregulated TH metabolism, which may result in SKM dysfunction and intolerance to exercise in individuals with hypothyroidism. PURPOSE: Implement an in vitro model of hypothyroidism in SKM and determine the response of myogenic regulatory factor expression during several stages of myogenesis following TH depletion. Formoterol, an exercise mimetic, was also used to examine the effects of exercise signaling on myogenesis in TH depleted cells. METHODS: Human SKM myoblasts (n = 6 per group) were cultured and differentiated until mature myotube formation (Day 6). Groups included control cells (CON), TH depleted cells (ThD), and TH depleted cells plus formoterol stimulation (ThD+F; 30nm for 3h). Total RNA was extracted during mid-myogenesis (Day 4) and at terminal differentiation (Day 6). Gene expression for myogenic regulatory factors (Myf5, MyoD, MyoG) was determined by qPCR. RESULTS: ThD decreased Myf5 at both Day 4 and Day 6 compared to control (P\u3c0.001). Myf5 was increased following ThD + F compared to ThD at Day 4 (P\u3c0.05). MyoD decreased following ThD at both Day 4 and Day 6 (P\u3c0.001). Further, MyoD was decreased following ThD + F at both Day 4 and Day 6 compared to ThD (P\u3c0.001). ThD had no effect on MyoG at Day 4 and Day 6; however, MyoG was decreased following ThD + F compared to ThD and control at both time points (P\u3c0.001). Data are expressed as mean ± SEM. CONCLUSION: TH depletion had no effect on MyoG but did reduce the expression of both Myf5 and MyoD at both Day 4 and Day 6. Additionally, ThD+F resulted in the lowest expression of MyoG and MyoD for both time points. These results indicate TH depletion and formoterol stimulation may inhibit myotube maturation

Mitochondrial Biogenesis is Dysregulated in Thyroid Hormone Depleted Muscle Cells Despite Stimulatory Effects of Formoterol

Skeletal muscle (SKM) is an important regulator of metabolism and adaptations from exercise training influences mitochondrial function. Thyroid hormone (TH) is a regulator of SKM processes, including mitochondrial biogenesis. PURPOSE: To use an in vitro model of hypothyroidism to test the hypothesis that SKM cells will have dysregulated mitochondrial homeostasis. Additionally, the exercise mimetic, formoterol, was used to determine the effects of exercise signaling on mitochondrial biogenesis. METHODS: Human SKM myoblasts (n = 6 per group) were cultured and differentiated until mature myotube formation (Day 6). Groups included control cells (CON), TH depleted cells (ThD), and TH depleted cells plus formoterol stimulation (ThD+F; 30nM for 3h). Total RNA was extracted during mid-myogenesis (Day 4) and at terminal differentiation (Day 6). Gene expression for Peroxisome Proliferator-Activated Receptor Gamma Coactivator-1 Alpha (PGC-1α), Mitochondrial Transcription Factor A (TFAM), and Nuclear Respiratory Factor 1 (NRF1) was determined by qPCR. Data was analyzed by repeated measures ANOVA. RESULTS: PGC-1α: D4 ThD was decreased compared to D4 ThD+F (-4.6); D4 ThD+F was increased compared to D4 CON (4.6); D6 CON was decreased compared to D6 ThD+F (-2.9); D6 ThD was decreased compared to D6 ThD+F (-3.7). TFAM: D4 ThD+F was greater than D4 CON (3.6); D4 ThD+F was greater than D6 ThD+F (3.6); D6 ThD was decreased compared to D6 CON (-0.55); D6 ThD+F was decreased compared to D6 CON (-0.63). NRF1: D4 ThD was decreased compared to D4 CON (-0.31); D4 ThD was greater than D4 ThD+F (0.36); D4 ThD was greater than D6 ThD (0.17); ThD+F was decreased compared to D4 CON (-0.67); D6 CON was decreased compared to D4 CON (-0.18); D6 ThD was decreased compared to D6 CON (-0.3); D6 ThD+F was decreased compared to D6 CON (-0.42). All reported differences are significant (p \u3c 0.05). Data are expressed as fold changes. CONCLUSION: ThD media resulted in reduced NRF1 signaling in both D4 and D6 with a subsequent decrease in D6 only for TFAM. Formoterol resulted in the expected stimulation of PGC-1α at both D4 and D6, but subsequent signaling for genes associated with mitochondrial biogenesis common to PGC-1α stimulation were lost as a result of TH depletion at D6 only for TFAM and both D4 and D6 for NRF1