A Review of Athletic Energy Expenditure, Using Skiing as a Practical Example

In this review we analyze competition sports, particularly downhill speed skiing and cross-country skiing, in terms of physical performance. The effects of various forces/parameters on athletic performance are summarized, and metabolic energy cost and mechanical power output are reviewed. The primary factors contributing to energy loss in the athlete are drag, friction between athlete and ground, and gravitational force (i.e., the movement of body segments in the gravitational field). According to previous reports the latter is the most significant factor. However, estimated levels of energy expenditure, occurring as a direct result of gravitational force, vary considerably depending on the method used in the analysis. We also demonstrate the importance of changes in friction and drag in athletic performance, using practical examples from skiing.