title: Hydration status of rugby league players during home match play throughout the 2008 Super League season.
abstract: The hydration status of rugby league players during competitive home match play was assessed throughout the 2008 Super League season. Fourteen players from 2 Super League clubs were monitored (72 observations). On arrival, 2 h prior to kick off, following normal prematch routines, players' body mass were measured following a urine void. Prematch fluid intake, urine output, and osmolality were assessed until kick off, with additional measurements at half time. Fluid intake was also monitored during match play for club B only, and final measurements of variables were made at the end of the match. Mean body mass loss per match was 1.28 ± 0.7 kg (club A, 1.15 kg; club B, 1.40 kg), which would equate to an average level of dehydration of 1.31% (mass loss, assumed to be water loss, expressed as a percentage of body mass), with considerable intra-individual coefficient of variation (CV, 47%). Mean fluid intake for club B was 0.64 ± 0.5 L during match play, while fluid loss was 2.0 ± 0.7 L, with considerable intra-individual CV (51% and 34%, respectively). Mean urine osmolality was 396 ± 252 mosm·kg-1 on arrival, 237 ± 177 mosm·kg-1 prematch, 315 ± 133 mosm·kg-1 at half time, and 489 ± 150 mosm·kg-1 postmatch. Body mass losses were primarily a consequence of body fluid losses not being completely balanced by fluid intake. Furthermore, these data show that there is large inter- and intra-individual variability of hydration across matches, highlighting the need for future assessment of individual relevance.
authors.affiliation: Carnegie Faculty, Carnegie Research Institute, Leeds Metropolitan University, Leeds, UK. J.Ohara@leedsmet.ac.uk
authors.forename: John Paul
authors.initials: JP
authors.lastname: O'Hara
authors.forename: Benjamin Lee
authors.initials: BL
authors.lastname: Jones
authors.forename: Costas
authors.initials: C
authors.lastname: Tsakirides
authors.forename: Sean
authors.initials: S
authors.lastname: Carroll
authors.forename: Carlton Brian
authors.initials: CB
authors.lastname: Cooke
authors.forename: Roderick Frederick Gerardus Joseph
authors.initials: RF
authors.lastname: King
mesh_terms: D000328:Adult; D000465:Algorithms; D056352:Athletes; D001835:Body Weight; D003681:Dehydration / Q000175:diagnosis*; D004326:Drinking; D005538:Football; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D009994:Osmolar Concentration; D005082:Physical Exertion / Q000502:physiology; D015203:Reproducibility of Results; D013997:Time Factors; D006113:United Kingdom; D014556:Urine / Q000737:chemistry; D014882:Water-Electrolyte Balance; D055815:Young Adult