title: Exercise-induced dehydration does not alter time trial or neuromuscular performance.
abstract: This study examined the effect of exercise-induced dehydration by ~4% body mass loss on 5-km cycling time trial (TT) performance and neuromuscular drive, independent of hyperthermia. 7 active males were dehydrated on 2 occasions, separated by 7 d. Participants remained dehydrated (DEH, -3.8±0.5%) or were rehydrated (REH, 0.2±0.6%) over 2 h before completing the TT at 18-25 °C, 20-30% relative humidity. Neuromuscular function was determined before dehydration and immediately prior the TT. The TT started at the same core temperature (DEH, 37.3±0.3°C; REH, 37.0±0.2 °C (P>0.05). Neither TT performance (DEH, 7.31±1.5 min; REH, 7.10±1.3 min (P>0.05)) or % voluntary activation were affected by dehydration (DEH, 88.7±6.4%; REH, 90.6±6.1% (P>0.05)). Quadriceps peak torque was significantly elevated in both trials prior to the TT (P<0.05), while a 19% increase in the rate of potentiated peak twitch torque development (P<0.05) was observed in the DEH trial only. All other neuromuscular measures were similar between trials. Short duration TT performance and neuromuscular function are not reduced by dehydration, independent of hyperthermia.
authors.affiliation: School of Biomedical Sciences, Charles Sturt University, Bathurst, Australia.
authors.forename: C J
authors.initials: CJ
authors.lastname: Stewart
authors.affiliation: School of Human Movement Studies, Charles Sturt University, Bathurst, Australia.
authors.forename: D G
authors.initials: DG
authors.lastname: Whyte
authors.affiliation: School of Biomedical Sciences, Charles Sturt University, Bathurst, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Cannon
authors.affiliation: School of Exercise Science, Australian Catholic University, Melbourne, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Wickham
authors.affiliation: School of Biomedical Sciences, Charles Sturt University, Bathurst, Australia.
authors.forename: F E
authors.initials: FE
authors.lastname: Marino
mesh_terms: D000328:Adult; D054874:Athletic Performance / Q000502:physiology*; D001642:Bicycling / Q000502:physiology*; D015992:Body Mass Index; D001831:Body Temperature / Q000502:physiology; D003681:Dehydration / Q000503:physiopathology*; D005080:Exercise Test; D005440:Fluid Therapy; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology*; D013647:Task Performance and Analysis; D013997:Time Factors; D055815:Young Adult