Hydration strategies of professional elite rugby league referees during super league matches

Due to the focus of research within athletic populations, little is known about the hydration strategies of rugby league referees. We observed all 8 full-time professional referees, during 31 Super League matches to investigate the drinking strategies and magnitude of dehydration (body mass loss) experienced by referees during match play. Referees arrived and remained euhydrated (urine osmolality; pre and post-match 558 ± 310 and 466 ± 283 mOsmol•kg-1). Mean body mass change was -0.7 ± 0.8%, fluid loss was 890 ± 435 g and fluid intake was 444 ± 167, 438 ± 190, 254 ± 108 and 471 ± 221 g during pre-match, first-half, half-time and second-half. This study suggests elite referees adopt appropriate hydration strategies during match-play to prevent large reductions in body mass, although individual variability was observed. Future research should investigate dehydration in referees from other sports and the effects on refereeing performance

The Effect of Pre-exercise Galactose and Glucose Ingestion on High-Intensity Endurance Cycling

ABSTRACT This study evaluated the effects of the pre-exercise (30 minutes) ingestion of galactose (Gal) or glucose (Glu) on endurance capacity as well as glycaemic and insulinaemic responses. Ten trained male cyclists completed three randomised high-intensity cycling endurance tests. Thirty minutes prior to each trial cyclists ingested 1 litre of either 40g of glucose, 40g of galactose, or a placebo in a double blind manner. The protocol comprised: 20 minutes of progressive incremental exercise (70% to 85% maximal power output (W max )); ten 90 second bouts at 90% W max , separated by 180 seconds at 55% W max ; 90% W max until exhaustion. Blood samples were drawn throughout the protocol. Times to exhaustion were longer with Gal (68.7±10.2 minutes, P=0.005) compared to Glu (58.5±24.9 minutes), with neither being different to placebo (63.9±16.2 minutes). Twenty-eight minutes following Glu consumption, plasma glucose and serum insulin concentrations were higher than with Gal and placebo (P<0.001). Following the initial 20 minutes of exercise, plasma glucose concentrations increased to a relative hyperglycaemia during the Gal and placebo, compared to Glu condition. Higher plasma glucose concentrations during exercise, and the attenuated serum insulin response at rest, may explain the significantly longer times to exhaustion produced by Gal compared to Glu. However, neither carbohydrate treatment produced significantly longer times to exhaustion than placebo, suggesting that the pre-exercise ingestion of galactose and glucose alone is not sufficient to support this type of endurance performance

Novel essential amino acid supplements enriched with L-leucine facilitate increased protein and energy intakes in older women: a randomised controlled trial

Background: Inadequate protein intake (PI), containing a sub-optimal source of essential amino acids (EAAs), and reduced appetite are contributing factors to age-related sarcopenia. The satiating effects of dietary protein per se may negatively affect energy intake (EI), thus there is a need to explore alternative strategies to facilitate PI without compromising appetite and subsequent EI. Methods: Older women completed two experiments (EXP1 and EXP2) where they consumed either a Bar (565 kJ), a Gel (477 kJ), both rich in EAAs (7.5 g, 40% L-leucine), or nothing (Control). In EXP1, participants (n=10, 68±5 years, mean±SD) consumed Bar, Gel or Control with appetite sensations and appetite-related hormonal responses monitored for one hour, followed by consumption of an ad libitum breakfast (ALB). In EXP2, participants (n=11, 69±5 years) ingested Bar, Gel or Control alongside an ALB. Results: In EXP1, EI at ALB was not different (P=0.674) between conditions (1179±566, 1254±511, 1206±550 kJ for the Control, Bar, and Gel respectively). However, total EI was significantly higher in the Bar and Gel compared to the Control after accounting for the energy content of the supplements (P<0.0005). Analysis revealed significantly higher appetite Area under the Curve (AUC) (P<0.007), a tendency for higher acylated ghrelin AUC (P=0.087), and significantly lower pancreatic polypeptide AUC (P=0.02) in the Control compared with the Bar and Gel. In EXP2, EI at ALB was significantly higher (P=0.028) in the Control (1282±513 kJ) compared to the Bar (1026±565 kJ) and Gel (1064±495 kJ). However, total EI was significantly higher in the Bar and Gel after accounting for the energy content of the supplements (P<0.007). Conclusions: Supplementation with either the Bar or Gel increased total energy intake whether consumed one hour before or during breakfast. This may represent an effective nutritional means for addressing protein and total energy deficiencies in older women