Average power output during (and in the final 15 minutes) of PT2 were significantly reduced in PL, demonstrating the contrasting benefits of CPE. Whilst the type and quantity of CHO has been shown to enhance exogenous CHO oxidation rates [3, 7, 18], late stage performance enhancement
may still occur with more conservative ingestion rates. By the start of PT2, during the CPE trial, participants had consumed a selleck kinase inhibitor total of 158.5 g CHO or 37.3 g.hr-1. Comparable ingestion rates have been shown to enhance late stage exercise performance elsewhere [22] despite being below known optimal delivery rates of 1-1.2 g.min-1 or 60-70 g.hr-1 [16]. It is most likely that any ergogenic or recovery effects from the CPE beverage are explained by the PLX4032 price www.selleckchem.com/products/VX-680(MK-0457).html combination of the maltodextrin and dextrose formulation. It has been demonstrated that the inclusion of multiple carbohydrates will result in higher exogenous carbohydrate oxidation (CHOEXO) rates
[23]. The combined uptake of total sugars from the sodium dependent glucose transporter (SGLT1) and GLUT5 intestinal transport mechanisms provides potential for maximal exogenous oxidation rates [3]. Whilst the oxidation rates of both dextrose and maltodextrin are similar, the inclusion of maltodextrin reduces beverage osmolarity, hence increasing the potential for carbohydrate delivery to the intestinal lumen, as well as fluid uptake. Furthermore, the inclusion of sodium to the test beverage is known to enhance carbohydrate bioavailability [24]. Despite relatively low CHO ingestion rates employed in the current study, an enhancement in both CHO delivery and CHOEXO would still have a resultant sparing or even suppressing effect on endogenous CHO utilisation [25], as well as maintaining the CHOTOT observed between performance bouts. As CHOEXO rates have typically been shown Dichloromethane dehalogenase to plateau after 90 minutes of steady state exercise, this in part explains the ergogenic potential observed in PT2 with CPE. Alternatively, as CHO ingestion rates were below optimal delivery levels, it is possible that the co-ingestion
of protein may have provided additional ergogenic value through increased caloric content. Whilst it has been suggested the addition of approximately 2% protein to a CHO beverage has minimal effect on subsequent performance, or glycogen resynthesis [26, 27], other studies have demonstrated a positive effect of co-ingestion of protein on endurance performance [8, 9, 28, 29] and short term recovery [30]. When carbohydrate-protein beverages have been administered during acute recovery (in comparison to an iso-energetic carbohydrate beverage), there is supporting evidence that the addition of protein positively enhances repeated same day time to exhaustion trials [31, 32]. The most likely explanation for this is the higher caloric content of the beverages employed, in comparison to lower dose carbohydrate only beverages [32].