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Alaine Mills KINS 6130 November 16, 2010

Short-term High Fat Diet Prior to Carbohydrate Loading: Gender Differences on Perceived Performance and Time to Fatigue. Alaine Mills KINS 6130 November 16, 2010. Introduction. Fuel Sources during Endurance Exercise Carbohydrates and Fats Most important to ensure optimal performance

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Alaine Mills KINS 6130 November 16, 2010

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  1. Short-term High Fat Diet Prior to Carbohydrate Loading: Gender Differences on Perceived Performance and Time to Fatigue Alaine Mills KINS 6130 November 16, 2010

  2. Introduction • Fuel Sources during Endurance Exercise • Carbohydrates and Fats • Most important to ensure optimal performance • Protein • Plays a small energetic role during endurance activities

  3. The Importance of Carbohydrates for Endurance Athletes • Play a role in the rapid metabolizing of fats for energy • If liver & muscles are depleted of glycogen, athlete will experience extreme fatigue • “Hitting the wall” • Carbohydrate stores are limited • Needs increase for endurance exercise (Sedlock, 2008)

  4. The Importance of Carbohydrates for Endurance Athletes • The CNS relies on carbohydrates to function properly • Mental fatigue • The time to exhaustion during endurance • directly related to the initial levels of stored muscle glycogen (Sedlock, 2008)

  5. The Importance of Fats for Endurance Athletes • Fat becomes a primary source of energy • Endurance training improves the body's ability to utilize fats for energy • Able to mobilize fats from adipocytes making more fatty acids available to working muscle • Endurance training also improves the working muscle’s capacity to oxidize fats that are delivered (Sedlock, 2008)

  6. Carbohydrate Loading • Manipulating one’s diet to enhance performance • High carbohydrate diet several days prior to competition • Maximizing muscle glycogen levels before an exercise event to help prevent fatigue (Sedlock, 2008)

  7. Literature Review • Research on short term high fat diets prior to CHO loading (Lambert, 2001; Havemann, 2006; Burke, 2000) • Results: • Modified patterns of fuel substrate utilization • Enhanced subsequent exercise capacity • Maximized the capacity for fat oxidation • Increased reliance on fat • Decreased reliance on muscle glycogen

  8. Literature Review • Women oxidize more lipids during exercise than men (Tarnopolsky, 1993; Devries, 2006). • Lower RER • Greater Reliance on fat oxidation • Due to Estrogen? • Some studies done on carbohydrate loading showed no effects on women (Tarnopolsky, 2001).

  9. Literature Review • Gaps in Previous Research on High Fat Diets: • Primarily male subjects only (Lambert, 2001; Havemann, 2006; Burke, 2000) • Lack of female-male comparison • Primarily Cycling (Lambert, 1994; Goedecke, 1999; Van Zyl, 1996)

  10. Purpose • Therefore, the purpose of this study is to compare male and female endurance runners on perceived performance and time to fatigue after following a short-term high fat diet prior to carbohydrate loading.

  11. Research Hypotheses • Women will increase their time to fatigue significantly more than men. • Women will decrease their RPE score significantly more than men.

  12. Limitations • Convenience Sampling • Volunteers • No randomization • Internal & External Validity

  13. Delimitations • Only endurance runners • One age group • Only one type of diet will be analyzed

  14. Assumptions • Participants will not deviate from the assigned diet plan • Participants will give maximal effort throughout the study

  15. Participants • Convenience Sample • 20 volunteers who run 3 days per week • Average 30 minutes per session • Ages: 19-24 years old • College students • Grouped according to gender • Recruitment • Informed consent

  16. Preliminary Testing • Anthropometric Data • Height & Weight • Body Fat Percentage • BIA • Reliable (r= 0.95-0.987) • Criterion-Related Validity (Jackson,1988)

  17. Preliminary Testing • VO² Max Test • Modified Bruce Treadmill Test • Provides warm-up • Treadmill speed increases in speed and grade every 3 minutes. Stage Speed (mph) Grade (%) Duration (min) 0 1.7 0 3 .50 1.7 5 3 1 1.7 10 3 2 2.5 12 3 3 3.4 14 3 4 4.2 16 3 5 5.0 18 3 6 5.5 20 3 7 6.0 22 3

  18. Preliminary Testing • Bruce Treadmill Test • Stability Reliability • r=0.96 • Criterion-Related Validity • Expected relationships verified (Robinson,2001)

  19. RestingEnergyExpenditure CalculationsandActivityFactors BW = Body Weight in Kg World Health Organization, 2010

  20. Dietary Manipulations • NHANES Food Frequency Questionnaire

  21. Dietary Manipulations 7 days 3-days (Lambert,2001) (Havemann,2005)

  22. Performance Measurement • Time to Exhaustion • Treadmill run to exhaustion @70% VO²max • Time to Exhaustion : The point when the subject can no longer maintain exercise intensity • For 15 seconds • Reliability • “Finding that there was no significant difference between trials enables future researchers to utilize the Robinson protocol with confidence that the trials will consistently be the same.” (Robinson, 2001) • Face Validity (Walsh, 2010)

  23. Performance Measurement • Rate of Perceived Exertion • Validated Borg RPE Scale • Criterion-Related Validity • Correlation w/ HR • Reliable (r=0.86) (Chen, 2002) • An ordinal scale • Verbally Explained • The greater the exertion felt the greater the number reported by the individual being tested

  24. Procedure • Trial 1 • Prior to any dietary manipulations • Standard Warm-up • Timed run to Exhaustion • Evaluation of RPE every 3 minutes

  25. Procedure • Diets Begin • High Fat Diet for 7 days • Carbohydrate Loading for 3 days following the High Fat Diet • Trial Two • Day 11 • Performed the same way as trial 1

  26. Statistical Analysis • Two way ANOVA with Repeated Measures • Independent Variable: Gender (Male and Female) • Dependant Variable • Time to Exhaustion (Pre and Post) • Two way ANOVA with Repeated Measures • Independent Variable: Gender (Male and Female) • Dependant Variable • RPE (Pre and Post) • α < .05

  27. References • Baechle, T.R., and R.W. Earle, eds. (2008). Essentials of Strength Training and Conditioning, 3rd ed. Champaign, IL: Human Kinetics. • Lambert, E.V., Goedecke, J.H., Zyl, C.V., Murphy, K., Hawley, J.A., Dennis, S.C., & Noakes, T.D.(2001). High fat diet versus habitual diet prior to carbohydrate loading: Effects on exercise metabolism and cycling performance. International Journal of Sport Nutrition and Exercise Metabolism,11(2), 209-225. • Venables, M.C., Achten, J., &Jeukendrup, A.E. (2005). Determinants of fat oxidation during exercise in healthy men and women: A cross-sectional study. J.Appl Physiol, 98(1), 160-167. • Havemann, L., West, S.J., Goedecke, J.H., Macdonald, I.A., St. Clair Gibson, A., Noakes, T.D. & Lambert, E.V. (2006). Fat Adaptation followed by carbohydrate loading compromises high-intensity sprint performance. J Appl Physiol, 10,0 194-202. doi:10.1152/japplphysiol.00813.2006 • Sherman, M.W., & Leenders (1995). Fat loading: The next magic bullet?. International Journal of Sport Nutrition, 5(S1-S12) • Walsh, A.L., Gonzalez, A.M., Ratamess, N.A., Kang, J., & Hoffman, J.R. (2010). Improved time to exhaustion following ingestion of energy drink Amino Impact. Journal of the International Society of Sport Nutrition. 7(14), 1-6.

  28. References • Tarnopolsky, L.J., Tarnopolsky, S.A., & MacDougall, J.D. (1990). Gender differences in substrate for endurance exercise. J. Appl. Physiol, 68: 302-308 • Sedlock, D.A. (2008). The latest approach on carbohydrate loading: A practical approach. Current Sports Medicine Reports, 7 (4), 209-213. • Burke, L.M., Angus, D.J., Cox, R.C., Cummings, N.K., Febbraio, M.A., Gawthorn, K.,Hawley, J.A., Minehan, M., Martin, D.T., & Hargreaves, M. (2000). Effect of fat adaptation and carbohydrate restoration on metabolism and performance during prolonged cycling. J Appl Physiol, 89(6), 2413-2421. • Tarnopolosky, M.A., Zawada, C., Richmond, L.B., Carter, S., Shearer, J., Graham, T., & Philips, S.M. (2001). Gender differences in carbohydrate loading are related to energy intake. J. Appl Physiol, 91(1), 225-230. • Conlee, R.K., Hammer, R.L., Winder, W.W., Bracken, M.L., Nelson, A.G., & Barnett, D.W. (1990). Glycogen relpletion and exercise endurance in rats adapted to a high fat diet. Metabolism, 39 (3), 289-294. • Lambert, E.V., Speechly, D.P., Dennis, S.C., Noakes, T.D. (1994). Enhanced endurance in trained cyclists during moderate intensity exercise following 2 weeks adaptation to high fat diet. Eur J Appl Physiol, 69, 287-293.

  29. References • Weltman, A., Snead, D., Stein, P., Seip, R., Schurrer, R., Rutt, R., & Weltman, J. (2007). Reliability and validity of a continuous incremental treadmill protocol for the determination of lactate threshold, fixed blood lactate concentrations, and VO2 max. Int J Sports Med, 11 (1), 26-32. • Chen, M.J., Fan, X., Moe, S.T. (2002). Criterion-related validity of the Borg ratings of percieved exertion scale in healthy individuals: A meta-analysis. Journal of Sports Sciences, 11 (1), 873-899. • Billat, V., Renoux, J. C., Pinoteau, J., & Petit, B. (1994). Reproducibility of running time to exhaustion at VO2 max in subelite runners. Medicine and Science in Sports and Exercise, 26 (2), 254.

  30. References • A. S. Jackson, M. L. Pollock, J. E. Graves and M. T. Mahar (1988). Reliability and validity of BIA in determining body composition. J Appl Physiol .64: 529-534 • Robinson, E.M., Graham, L.B., Headley, S.A. (2001). The Reliability of a run to exhaustion. Journal of Exercise Physiology. • Bruce, R. A., F. Kusomi, and D. Hosmer. Maximal oxygen uptake and nomographic assessment of functional aerobic impairment in cardiovascular disease. Am. Heart J. 85: 546–562, 1973.

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