title: The influence of ice slurry ingestion on maximal voluntary contraction following exercise-induced hyperthermia.
abstract: The purpose of this study was to determine whether ingestion of a small bolus of ice slurry (1.25 g kg(-1)) could attenuate the reduction in maximal voluntary isometric contraction (MVC) torque output during a 2-min sustained task following exercise-induced hyperthermia. On two separate occasions, 10 males (age: 24 ± 3 years, .VO(2peak): 49.8 ± 4.7 ml kg(-1) min(-1)) ran to exhaustion at their first ventilatory threshold in a hot environment (34.1 ± 0.1°C, 49.5 ± 3.6% RH). Prior to and after exercise, subjects performed a 2-min sustained MVC of the right elbow flexors in a thermoneutral environment (24.6 ± 0.8°C, 37.2 ± 4.5% RH). The post exercise MVC was performed immediately following the ingestion of either 1.25 g kg(-1) of ice slurry (-1°C; ICE) or warm fluid (40°C; CON), in a counterbalanced and randomised order. Run time to exhaustion (42.4 ± 9.5 vs. 41.7 ± 8.7 min; p = 0.530), and rectal (39.08 ± 0.30 vs. 39.08 ± 0.30°C; p = 0.934) and skin temperatures (35.26 ± 0.65 vs. 35.28 ± 0.67°C; p = 0.922) and heart rate (189 ± 5 vs. 189 ± 6 beats min(-1); p = 0.830) at the end of the run were similar between trials. Torque output during the post-exercise 2-min sustained MVC was significantly higher (p = 0.001) following ICE (30.75 ± 16.40 Nm) compared with CON (28.69 ± 14.88 Nm). These results suggest that ice slurry ingestion attenuated the effects of exercise-induced hyperthermia on MVC, possibly via internal thermoreceptive and/or temperature-related sensory mechanisms.
authors.affiliation: School of Exercise, Biomedical and Health Sciences, Edith Cowan University, 270 Joondalup Drive, Joondalup, WA 6027, Australia. r.siegel@ecu.edu.au
authors.forename: Rodney
authors.initials: R
authors.lastname: Siegel
authors.forename: Joseph
authors.initials: J
authors.lastname: Maté
authors.forename: Greig
authors.initials: G
authors.lastname: Watson
authors.forename: Kazunori
authors.initials: K
authors.lastname: Nosaka
authors.forename: Paul B
authors.initials: PB
authors.lastname: Laursen
mesh_terms: D000328:Adult; D001628:Beverages; D001833:Body Temperature Regulation / Q000502:physiology; D004435:Eating / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005334:Fever / Q000209:etiology* / Q000503:physiopathology / Q000517:prevention & control; D006801:Humans; D007053:Ice; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology; D019415:Torque; D014882:Water-Electrolyte Balance / Q000502:physiology; D055815:Young Adult
chemical_list: D007053:Ice