On the potential of various approaches in load analysis to reduce the frequency of sports injuries.

The purpose of this paper is to discuss various approaches used in load analysis with special consideration of whether there is some evidence that these approaches have actually contributed to a reduction of sport injuries and whether these approaches have the theoretical potential to reduce the frequency of injuries at all. Two possible approaches are compared. The 'cause-effect approach' uses the estimation of internal stress. It is proposed that a comparison of the internal stress with the critical stress limits for an anatomical structure of interest may not help to reduce the frequency of injuries for two reasons. Firstly, the estimation of the critical stress limits and the internal stress may have significant errors which inhibit possible conclusions. Secondly, the information provided by the comparison of internal stress and critical stress limits was implicitly available in the injury frequencies and no new knowledge has been added. It is proposed that stresses estimated from model calculations can successfully be used to reduce the frequency of injuries if they are compared (comparison technique) with stresses estimated for comparable situations (e.g. shoes with and without orthotics). The 'empirical approach' is based on the assumption that the knowledge of the mechanisms of an injury is not a prerequisite for the reduction of the frequency of injuries. The approach establishes statistical correlations between factors related to injuries on one side and specific injuries or groups of injuries on the other side. This approach has frequently been used in the development of sport shoes. It is speculated that studies using an empirical approach have the potential to actually reduce the frequency of injuries. The conclusive evidence that biomechanical research in load analysis has in fact contributed to a reduction of the frequency of injuries is still missing for both discussed approaches.