Muscle control in elite alpine skiing. Med. Sci. Sports Exerc., Vol. 31, No. 7, pp. 1065-1067, 1999.
Purpose: The purpose of this study was to determine whether muscle control may be influenced by accelerative forces brought about by the downhill displacement of body mass in combination with the sharp turns during alpine skiing.
Methods: Sixteen elite skiers performed either super G (SG), giant slalom (GS), slalom (SL), or freestyle mogul (FM) skiing. Knee and hip joint angles and electromyographic (EMG) activity of the knee extensors were recorded.
Results: During the course of a turn, the minimum (deepest stance position) knee angle of the outside (main load-bearing) leg ranged from 60° to 100°, where the smallest angle was obtained in the FM event. Among the traditional alpine disciplines, smaller knee angles were obtained in the high-speed events (i.e., knee angle: SG<GS<SL). Knee angular velocity of the outside leg ranged from 15° to 300°·s−1, with the slower movements in the high-speed disciplines (i.e., knee angular velocity: SG<GS<SL<FM). In all disciplines, EMG activity reached near-maximal levels during the course of a turn. In SG, GS, and SL, but not in FM skiing, a marked predominance of eccentric over concentric muscle actions was observed. The dominance of slow eccentric muscle actions has not been observed in other athletic activities.
Conclusions: We believe these results have important implications for the design of specific training models.
Department of Orthopedic Surgery at Daderyd Hospital, Department of Physiology and Pharmacology, Defence Research Establishment, Division of Human Studies, Department of Aviation Medicine, Karolinska Institutet, SE-171 77 Stockholm, SWEDEN
Submitted for publication April 1997.
Accepted for publication March 1998.
The participation of members and coaches of the Swedish National Teams is acknowledged.
This study was in part funded by the Swedish Center for Sports performance (CPU).
Address for correspondence: Hans E. Berg, M.D., Department of Orthopedic Surgery, Karolinska Institutet at Danderyd Hospital, SE-18288 Danderyd/Stockholm, Sweden.