Browsing by Author "Irvine, Chris"
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Item Muscle damage, inflammation, and muscular performance following the physical abilities test in professional firefighters(May-23) Sokoloski, Matthew Lawrence 1992-; Rigby, Brandon; Irvine, Chris; Bosak, Andy; King, George; Irvine, Chris; Bosak, Andy; Biggerstaff, Kyle D; King, GeorgeProper monitoring of fatigue, cardiovascular disease, and muscular damage may be used to decrease the high levels of cardiovascular disease, overuse musculoskeletal injuries, and workers compensation claims within the profession of firefighting. The purpose of this study was to examine muscle damage, muscular fatigue, and inflammation responses following a typical firefighting shift. Twenty-four professional firefighters completed two Physical Abilities Tests to standardize the tasks typically performed in a day of work and elicit similar physiological responses. These individuals were then monitored for 48hrs. Prior to and 48hrs following the PAT these individuals were evaluated for changes in strength, power, range of motion, as well as blood markers including myoglobin, TNF-α, and C-Reactive Protein. Following the PAT significant differences in myoglobin (p < 0.05), grip strength (p < 0.05), vertical jump (p < 0.05), and sit-and-reach (p < 0.05) were observed. No differences in TNF-α or C-Reactive Protein were observed (p > 0.05). Twenty-four hours following a shift firefighter still show decreased levels of strength, power, and range of motion. This may lead to decreases in performance and an increased risk of injury.Item The influence of a whey protein preload prior to carbohydrate consumption on cycling performance(9/30/2019) Irvine, Chris; Ben-Ezra, VictorThe addition of whey protein co-ingested with a carbohydrate source during aerobic exercise has been theorized to augment insulin secretion, invoke a muscle glycogen sparing effect, improve glycemic control, and ultimately improve endurance performance. However, previous literature has reported a discrepancy between the performance measures outcomes. This study aimed to examine if 0.7 g/kg/LBM of whey protein isolate administered as a preload to a glucose bolus of 0.9 g/kg/LBM influences cycling performance and the metabolic profile during a 60 min cycling performance trial. Ten recreationally trained cyclists and triathletes (age 32.2 ± 8.7 years; weight 81.4 ± 11.5 kg; body fat 23.7 ± 5.1%; lactate threshold 203 ± 37.6 W) completed two experimental trials. Each trial was assigned in a counter-balanced order and separated by at least one week. For each experimental trial, participant reported to the exercise physiology lab in a 10-12 hour fasted state. Each participant was required to perform a cycling performance test, which consisted of cycling for 30 min at 90% LT, followed by a 30 min time trial. Prior to the cycling performance test, participants consumed either a whey protein isolate preload (0.7 g/kg/LBM) or a placebo 20 min prior to the consumption of a glucose beverage (0.9 g/kg/LBM). The glucose beverage was consumed 10 min prior to the cycling performance test. Following the completion of both experimental trials, results indicated there were no significant differences in overall time trial performance (WP 16.8 ± 0.34 km; PL 17 ± 0.4 km; p = .346). The whey protein stimulated a significant increase in plasma insulin concentrations at time point 0 (WP = 222.88 ± 45.1 pg/ml; PL = 85.95 ± 45.1 pg/ml; p = .047) compared to the placebo trial. The increase in insulin during WP stimulated a significant interaction effect for plasma glucose concentrations (p = 0.009) between the two trials, however, there were no significant differences. The whey protein stimulated a significant increase in plasma glucagon concentrations for timepoint -10, 0, 15, 30, 45, and 60 when compared to the PL trial (all values p < .05). There were no reported differences in RER, NEFA, or any other variables between the two experimental trials. Although there were significant metabolic alterations due to the consumption of the whey protein preload, this did not influence overall cycling performance or substrate utilization.