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Transcript of Goal
Introduce the topic
Gaps in the research
Goal: Research Question
Background: Why are carbohydrates (CHO) so important?
Primary fuel source to produce ATP (adenosine triphosphate) during abiding exercise
(Widrick et al, 1993)
CHO stores become limiting during exercise - specifically during prolonged exercise
(Coyle et al, 1992; Tsintzas et al, 1998)
Hypoglycemia and reduced CHO oxidation rates cause subsequent decrease in exercise performance
(Tsintzas et al, 1998)
CHO Supplementation During Exercise
CHO ingestion during prolonged exercise produces significant ergogenic effects
(Bjorkman et al, 1984)
Empirical evidence suggests CHO feeding improves endurance performance at ~1h
(Below et al, 1995; Jeukendrup et al, 2003)
Mechanisms explaining the improvement are unclear
(Below et al, 1995; McConnell et al, 2005; Carter et al, 2004)
Sparing hepatic glycogen
(Bosch et al, 1994; Jeukendrup et al, 1999)
Maintaining blood glucose concentration
(Coyle et al, 1986)
(Coyle et al, 1986)
Mechanisms by Which CHO Improve Performance
During high intensity exercise of ~1h duration, blood glucose concentrations are well maintained
(Carter et al, 2004)
Many studies found no clear metabolic effect
(Carter et al, 2004; McConnell et al, 2000)
Central, non metabolic effect through the activation of the CNS via orphangeal receptors
(Maresh et al, 2001; Riebe et al, 1997)
REVIEW OF THE LITERATURE
A. Pottier, J. Bouckaert, W. Gilis, T. Roels and W. Derave (2010)
Aim: Explore the effects of ingestion or mouth rinse of a 6% isotonic solution upon a 1-h high intensity cycle time trial.
~2.5 minutes shorter to complete the time trial with CES compared with the placebo
Literature Review - Pottier et al (2010)
No significant difference in time trial performance with ingestion of CES compared to placebo
Findings - Pottier et al (2010)
Rinsing the mouth with a 6% isotonic CES (carbohydrate electrolyte solution) improved performance but not ingestion of the same solution
Critique - Pottier et al (2010)
Blood glucose levels were higher during the CHO trials compared with placebo
I. Rollo, C. Williams and M. Nevill (2011)
Aim: Explore the effects of ingesting a 6.4% carbohyrate solution or mouth rinsing during a 1-h run.
Literature Review - Rollo et al 2011
CHO ingestion significantly improved running speed compared to the mouth rinse and placebo
Findings - Rollo et al (2011)
Mouth rinsing then ingesting a CES significantly improved running performance compared to just rinsing the same solution or ingesting a placebo
Critique - Rollo et al (2011)
Standardised the time the solution was kept in the oral cavity
Results of Pottier et al (2010) and Rollo et al (2011) were contradictory
Only two studies as of yet to test effects of CHO mouth rinse versus ingestion during a 1-h endurance activity
Both tested the effects of an ~6% CES
Lack of clear mechanism due to lack of metabolic changes seen in both studies point to a central effect
Gaps in the Research
Limited research into the effects of the same CHO solution ingested versus mouth rinse
Mechanism thought to be a central effect, through orphangeal receptors activating the central nervous system
Significance of ergogenic effects of mouth rinse compared to ingestion linked to length of time solution kept in oral cavity
Amount and composition of pre-exercise meals were not recorded
Dietary preparations can have large influence upon performance
(Beelen et al, 2009)
No clear mechanism was recorded which explained the significant difference in performance between the ingestion and mouth rinse respectively
During placebo trial, the solution was ingested
Lack of significance of the mouth rinse compared to placebo may have been resulting factor of the positive ergogenic effects of the ingestion of a fluid per se
The vast majority of studies have tested the effects of a 6% CHO solution as a mouth rinse
Clark (1926) highlighted 'Occupancy Theory'
Results have practical implications such as to reduce gastrointestinal distress, diabetic individuals
(Peters et al, 2000; Seckl et al, 1986)
Tsintzas and Williams (1998) - blood glucose concentrations drop less during running than cycling, endogenous CHO stores less limiting in Rollo's study (2011)
What effect does ingesting a 20% CHO solution have upon a 1-h cycle time- trial performance compared with mouth rinsing the same solution?