Biomechanics of cross-country skiing locomotion

Cross-country skiing constitutes ancestral method for moving along in a snow environment.A number of techniques have been developed to facilitate this. Among these techniques, one of them; namely the Diagonal Stride Technique( DST) has been described by authors as an extension of walking and running. Most biomechanical research studies have analysed the DST as a sporting activity leaving the locomotor strategies poorly described. This relationship to walking and running and the involvement of a gliding phase make the DST an interesting locomotion which may reflect a locomotor adaptation of human to the environment. The overall purpose of the research undertaken in this work was to determine the strategies employed by skiers to progress along the ground in the DST. Different analytical approaches were used to test the research question: those involved cycle patterns, joint angular kinematics,coordination and mechanical analyses of different skiing conditions. The DST with poles was tested for two different speeds. In addition,the DST was investigated without poles. The description of the joints angular kinematics showed that specific movement patterns and segmental organisation were required for skiing with a reference to walking and running. The DST locomotion was mechanically similar to running but involved a gliding phase. The generation of forward displacement was carried out using an effective sequencing of hip extension and knee and ankle extension. Poles were reported to contribute to the generation of upper and lower body propulsion strategies. They were also supposed to increase the balance of the skier by providing additional supports. The increase of speed was achieved through faster limb movements without change in the joints range of motion. The overall conclusion of this work is that although the DST could be related to running, the skiers developed some specific body segmental organisations to progress along the ground,in response to the properties of the environment and of the material.