Monday, 1 August 2011
International Sports Science & Sports Medicine Conference 2011 in Newcastle
I'm presenting some of my work at the upcoming ISSSM Conference in Newcastle (http://www.isssmc.com/). I will summarise all the latest sports nutrition and sports science research that will be presented at the conference. In the meantime, see below for the two studies that I will be presenting in Newcastle.
Effects of carbohydrate and caffeine co-ingestion on a reliable simulated soccer-specific protocol
MK Ranchordas, C Pattison. Department of Sport, Faculty of Health & Wellbeing, Sheffield Hallam University, Collegiate Crescent Campus, Ecclesall Road, Sheffield S10 2BP
The aim of this study was to evaluate the effect of co-ingesting carbohydrate and caffeine (CHO+CAF) in comparison to carbohydrate (CHO) and placebo (PLA), during a reliable soccer-specific test (Currell et al., 2009). 8 university-standard soccer players ingested a PLA, a 6.4% CHO or 6.4% CHO and 16 mg CAF (CHO+CAF) solution on three occasions, in a double-blind randomized cross-over design, with each trial separated by 7 days. The protocol was 90 min in duration, made up of ten 6 min exercise blocks, each followed by soccer-specific skills tests(agility, dribbling, heading and kicking accuracy). Dependant variables (Agility, dribbling, heading, kicking accuracy, glucose, lactate, HR and RPE) were analyzed using one-way repeated measures ANOVA. Significant difference (p < 0.05) was found between CHO+CAF, CHO and PLA for each of the soccer-specific skill tests. Significant improvement (p = 0.02) was observed in agility time in CHO vs. PLA trials, although no significant difference (p > 0.05) was reported for dribbling, heading and kicking accuracy. Blood glucose and lactate were elevated (p < 0.05) with CHO+CAF supplementation over PLA, but there was no difference (p > 0.05) compared to CHO. Blood glucose increased (p = 0.01) in the CHO trial compared to PLA, with no difference (p > 0.05) between CHO+CAF and CHO. No significant difference (p > 0.05) was reported for HR and RPE values across all trial conditions. Skill performance during simulated soccer activity improved with CHO+CAF supplementation in comparison to both CHO and PLA. CHO+CAF co-ingestion had no ergogenic benefit over CHO in the maintenance and availability of blood glucose however, CHO+CAF co-ingestion did allow players to sustain a higher work intensity as opposed to CHO and PLA beverages as shown by elevated blood lactate levels.
Effect of Acute L-Arginine Supplementation on 20 km time trial performance in competitive male cyclists
MK Ranchordas, T Whitehead. Department of Sport, Faculty of Health & Wellbeing, Sheffield Hallam University, Collegiate Crescent Campus, Ecclesall Road, Sheffield S10 2BP
Increasing literature has studied the effects of dietary nitrates and moreover, L-arginine supplementation on tolerance to exercise and O2 consumption during exercise. However, few studies have investigated the effects of L-arginine on performance measures such as a time trial. It was hypothesised that an acute 3-day L-arginine supplementation would elicit a significant improvement in performance and reduce oxygen consumption during a 20 km time trial. 6 healthy male competitive cyclists (23 ± 5 y) participated in a double-blind crossover study, and consumed either one 500 m placebo (PLA) or L-arginine (ARG) beverage, containing 6 g of L-arginine, over a 2 week testing period. Following a 3-day supplementation, participants completed a ramped incremental test to exhaustion, followed by an hours rest and subsequently a 20 km time trial. Time trial completion time was reduced by 34 seconds (PLA 32:38 ± 1:50 vs. ARG 32:04 ± 1:38 min, P<0.05), O2 consumption during the time trial was also reduced (PLA 51.57 ± 8.19 vs. ARG 47.46 ± 6.09 mL.kg.min-1, P<0.05). Furthermore, both systolic and diastolic blood pressure were greatly reduced (PLA 132 ± 7 vs. ARG 127 ± 7 mmHg P<0.05 and PLA 79 ± 5 vs. ARG 74 ± 5 mmHg respectively, P<0.05). However, no differences were seen in participants’ VO2max during the ramped incremental test to exhaustion (58 ± 8 vs. 58 ± 8 mL.kg.min-1, P>0.05) although Wpeak was higher during the same test (PLA 385 ± 38 vs. ARG 395 ± 39 W). In conclusion, acute 3-day L-arginine supplementation at a dose of 6 g.day-1 increases 20 km time trial performance and reduces O2 consumption during time trial performance, in addition to reducing systolic and diastolic blood pressure. However, L-arginine appears to have no effect upon VO2max