INTRODUCTION: To help understand how Alpine skiers cope with the stress of multiple weeks of training, this study attempted to maintain hydration levels, monitor carbohydrate (CHO) intake, and force feed some athletes with a carbohydrate-protein (CHO-P) supplement while taking characteristic measurements of fatigue of Alpine skiing over a two week period. METHOD: Eight male skiers completed the full protocol over two weeks of ski training. Four subjects were in the CHO-P group and four served as controls. All subjects skied with a Camelbak and drank 1-1.5L water/day and the CHO-P group consumed 5-6 Accel Gels/day during training. Dietary intake was measured and total daily carbohydrate (CHO) levels were calculated for each subject. Every 3rd day of training, subjects completed the following: 1.) Finger stick blood sample for Creatine Kinase (CK); 2.) A 60% MVC knee extension task (fixed at 120 degrees) to fatigue; 3.) Subjective ratings of quadriceps muscle soreness; and 4.) Training impulse (Trimp) as a product of perceived effort and number of training runs taken each day. RESULTS: Daily dietary CHO excluding the gels, Trimp, and muscle soreness were not different between groups or over time (repeated ANOVA, P>.05). There was a difference in CK levels between days (F=12.45, P<.05) rising from a mean (+SD) pre-ski level of 139.5+109.1 U/L to 561.8±301.9 U/L; however, the only difference was between Day 1 of the first week and all other days. There was a difference for 60%MVC time to fatigue (repeated ANOVA, F=5.29, P<.05). No differences between Days 1 and 3 of each week; but, by Day 6 of each week, there was a decrease in knee extensor muscle endurance. When CHO intake included Gels, a significant difference was noted between groups each day (repeated ANOVA, F=4.13, Pc.05) DISCUSSION: It was not surprising to see little difference in daily total CHO calorie intake between groups when Gel calones were not included. Everyone was offered the same menu items each day. Sustained elevated CK levels after day 1 probably reflect of muscle stress that neither the CHO-P nor maintaining hydration with water could prevent. CONCLUSION: Physiological demands for Alpine ski training exceed the CHO intake of young athletes in spite of encouragement from coaches and planned breaks to eat. Supplementing a skier's diet with 500-600 CHO-P Calories while ski race training, appears to provide enough energy to match the energy demand of a 3-4 hour training session on a glacier. ACKNOWLEDGEMENTS: The authors would like to thank Olin-Lacasse Ski Racing School, Timbertine Ski Area, and Camelbak, Inc. for their support in this study.
© Copyright 2012 Science and Skiing V. 5th International Congress on Science and Skiing, Dec. 14 - 19, 2010, St. Christoph am Arlberg. Veröffentlicht von Meyer & Meyer Sport (UK) Ltd.. Alle Rechte vorbehalten.