During competitive alpine skiing, the mechanical and metabolic demands on skeletal muscles are very high. Compared to other competitive sports, muscle recruitment pattern is special and characterized by a preponderance of eccentric activity (Berg & Eiken, 1999). In the view of the particular requirements of elite alpine skiing the scientific basis, on which training regimes and testing protocols are based, is narrow and not abreast with the recent developments in materials and technique. Methods: In the course of the study "Allalin 2000", we investigated the physiology of modern alpine skiing on elite junior alpine skiers (Vogt et al. 2005). Endurance- and power-tests were performed before and after a single but exhaustive training day on skis. During the training day, the athletes performed 16 slalom runs and muscle biopsies were taken from M. vastus lateralis before, after 4 and after 16 runs. Muscle glycogen content, fiber type composition and fiber crosssectional area were determined. Blood lactate concentration, heart rate and race-time were recorded for each run. Total energy consumption during skiing was determined by measurement of oxygen consumption with a portable gas analyser. Results: Energy consumption during competitive alpine skiing is high and depends predominately on carbohydrate metabolism. The reduction in muscle glycogen content was higher in type I than type II fibers. Glycogen was almost undetectable in some type I fibers at the end of the training. The ratio of type II to type I cross-sectional area, maximal power output during an endurance test and jump performance in a counter-movement jump-test as well as strength of quadriceps muscle during knee extension correlated significantly to ski specific performance (P < 0.05). No significant relationship was found between fiber-type composition (mean values: 65% type I, 35% type II) and ski specific performance. Discussion: The glycogen depletion results indicate that during competitive alpine skiing the type I muscle fibers are importantly recruited. Alpine skiers must take care to refill glycogen stores by optimizing the regeneration phase after training. Both high oxidative capacity (endurance, type I fibers) and muscle hypertrophy (power, type II fibers) seem to be good predictors of performance in competitive alpine skiers. Training regimes must be developed to improve energy providing systems by high amounts of endurance training. In the context of strength development, training should also be focused to improve muscle coordination during eccentric muscle activity. Chronic eccentric exercise training on specific developed devices appears to be a promising approach to improve performance and prevent injury in alpine skiers.
© Copyright 2005 International Congress Mountain & Sport. Updating study and research from laboratory to field. 11th-12th November 2005. Rovereto (TN) - Italy. Programme and book of abstracts. Published by Centro Interuniversitario di Ricerca in Bioingegneria e Scienze Motorie. All rights reserved.