Carbohydrate (CHO) loading does improve endurance performance.

Transcription

1 BPK 312 Nutrition for Fitness and Sport Carbohydrate (CHO) loading does improve endurance performance. Rey Arcega, Danielle Contreras, Jason Orey P-CP Presentations April 04,

2 Roadmap of Debate Carbohydrate loading as an Ergogenic Aid Hypothesis CHO clinical and non-clinical settings CHO mechanism of action Carbohydrate loading: Rey Arcega, Danielle Contreras, Jason Orey CHO Recommended Dietary Allowance (RDA) CHO loading research evidence in support positive ergogenic effects Research evidence in refute of ergogenic effects Conclusion 2

3 Point & Counter-Point Hypotheses Carbohydrate loading does improve endurance performance. Carbohydrate loading has no effect on endurance performance. 3

4 Carbohydrate Clinical Settings Supporting point hypothesis Pre-op CHO administration on grip strength, GI function & hospital stay following colorectal surgery Improve recovery of gut function (Noblett et al, 2006) 4

5 Carbohydrate Non-Clinical Settings Supporting point hypothesis CHO loading is recommended for endurance athletes partaking in events lasting longer than 90 minutes (Andrews et al, 2003). 5

6 Carbohydrate Mechanism of Action Supporting point hypothesis Increases glycogenesis Classic CHO loading method (Fogelholm, 1991). [Glucose] in blood delays onset of fatigue, sustained exercise intensity, improved performance (Andrews, 2003). Muscle glycogen provides most of the CHO during exercise as lactate turnover exceeds that of glucose. 6

7 Carbohydrate Mechanism of Action (Korla and Chanchal, 2014) 7

8 USDA recommends 45-65% of total caloric intake come from CHO. Carbohydrate loading: Rey Arcega, Danielle Contreras, Jason Orey RDA for Carbohydrate Supporting point hypothesis ACSM and ADA advises athletes to consume at rates of 0.7 g/kg body weight per hour during endurance events (Pfeiffer et al, 2012) 8

9 Carbohydrate Safe Level for Consumption Supporting point hypothesis In CHO loading 75-85% CHO is recommended to endurance athletes. Excess CHO intake is associated with weight gain and diabetes. 9

10 Research Evidence in Support of Positive Ergogenic Effects of CHO Loading 12 m, 6 fem runners 30-km time trial CHO group runs faster during last 5k 6 men finished faster (P<0.05) Control group decreased [blood glucose] 10 Trial 1 ( ), Trial 2 ( ). *P<0.05. (Williams et al., 1992)

11 Research Evidence in Support of Positive Ergogenic Effects of CHO Loading 8 fem. athletes km treadmill runs Blood glucose significantly higher at 40, 60, and 100 min during L +S, and at 80 and 100 during S and P. L+S S P *P significantly different from S, P<0.05. P significantly 11 different from L+S, P<0.05. (Andrews, 2003)

12 Point & Counter-Point Hypotheses Carbohydrate loading does improve endurance performance. Carbohydrate loading has no effect on endurance performance. 12

13 Research Evidence in Refute of CHO Loading Supporting C-P hypothesis Sherman Method of Carbohydrate Loading Muscle Glycogen levels and time to fatigue did not improve in females who carbohydrate loaded (Tarnopolosky et al, 1995) 13

14 Research Evidence in Refute of CHO Loading Supporting C-P hypothesis Stage of menstrual cycle was controlled for in the study Carbohydrate loading: Rey Arcega, Danielle Contreras, Jason Orey Potential differences in Glucose transporters (GLUT4) in men and women Total number of CHO ingested was lower in women than men Resp. Exchange Ratio (Tarnopolosky et al, 1995) CHO Loaded Men = CHO Loaded Women = Control Men = Control Women = 14

15 Research Evidence in Refute of CHO Loading Supporting C-P hypothesis Carbohydrate loading showed no statistically significant improvement in 100 km cycling time trials Double Blind Placebo Controlled Study (Burke et al, 2000) 15

16 Research Evidence in Refute of CHO Loading Supporting C-P hypothesis Financial rewards were given for completing the 100 km s fastest, or one of the sprints the fastest Time in the CHO loaded group improved by 1.5 minutes Carbohydrate loading: Rey Arcega, Danielle Contreras, Jason Orey (Burke et al, 2000) 16

17 mens-road-race 17

18 Conclusion Carbohydrate loading does improve endurance performance. Supports Point Hypothesis 18

19 References: Carbohydrate loading: Rey Arcega, Danielle Contreras, Jason Orey 1. Andrews, J. L., Sedlock, D. A., Flynn, M. G., Navalta J.W., & Hongguang Ji. Carbohydrate Loading and Supplementation in Endurance-trained Women Runners. J. Appl. Physiol. 95; Burke, L. M., Hawley, J. A., Schabort, E. J., St Clair Gibson, A., Mujika, I., & Noakes, T. D. Carbohydrate loading failed to improve 100-km cycling performance in a placebo-controlled trial. J. Appl. Physiol. 88(4); Fogelholm, G. M., Tikkanen, H. O., Naveri, H. K., Naveri, L. S., & Harkonen, M. H. Carbohydrate loading in practice: high muscle glycogen concentration is not certain. Br. J. Sports Med. 25(1); Korla, K., Chanchal, K. M. Modelling the Krebs cycle and oxidative phosphorylation. J. Biomo. Struct. Dyn. 32(2) Noblett, S. E., Watson, D. S., Huong, H., Davison, B., Hainsworth, P. J., & Horgan, A. F. Pre-operative oral carbohydrate loading in colorectal surgery: a randomized controlled trial. Colorectal Disease. 8(7); Pfeiffer, B., Stellingwerff, T., Hodgson, A. B., Randell, R., Pottgen, K., Res, P., Jeukendrup, A.E. Nutritional Intake and Gastrointestinal Problems During Competitive Endurance Events. Med. Sci. Sports Exerc. 44(2); Tarnopolosky, M. A., Atkinson, S. A., Phillips, S. M., & MacDougall, J. D. Carbohydrate loading and metabolism during exercise in men and women. J. Appl. Physiol. 78(4); Piacentini, M. F., Parisi, A., Verticchio, N., Comotto, S., Meeusen, R., & Capranica, L. No changes in time trial performance of master endurance athletes after 4 weeks on a low carbohydrate diet. Sport Sci. Health. 8(1); Williams, C., Brewer, J., & Walker, M. The effect of a high carbohydrate diet on running performance during a 30-km treadmill time trial. Eur. J. Appl. Physiol. 65; Yunsheng, M., Youfu, L., Chiriboga, D. E., Olendzki, B. C., Hebert, J. R., Wenjun, L., Leung K., Hafner, A. R., & Ira S. Ockene, I. S. Association between Carbohydrate Intake and Serum Lipids, J. Am. Coll. Nutr. 25(2);