Despite the growing interest in extreme sports around the world, researchers have rarely investigated the complex factors that have led to a developed commitment to extreme sports in recent years. Precisely, the social identity of ultramarathoners remains a research niche. The aim of the article is to analyze the impact of a sports event on shaping social identity of ultramarathon runners on the example of Karkonosze Winter Ultramarathon (held in Poland). The qualitative method used in the article-interviews with runners-made it possible to examine the factors that create social identity, among which the motives for participation, sports subculture, and the authenticity of the experience play a key role. The first part of the article describes the theoretical aspects of social identity in sport. The second, empirical part presents the research results supplemented by the statements of the contestants. In this case, the subject of analysis is the motives for participation in a winter ultramarathon and their characteristics. Lastly, the article analyzes the subculture of ultramarathoners and the experience of contestants' authenticity. The investigated winter ultramarathon created the perfect space for creation, deepening and celebrating the social identity of ultramarathoners assessed as a value in itself. The article enriches the present knowledge about the motivation of ultramarathoners because, unlike the results of quantitative research, it presents in-depth responses of runners who were not always concerned by existing research questionnaires.
Keywords: authenticity of experience; social identity; sports events; sports motivations; sports subculture; ultramarathon.