The number of tennis players experiencing pain and/or injuries has increased drastically during the last two decades. However, little is known about the etiology of tennis- related pain and injuries in the lower extremities. The purpose of the present study was to analyze systematically the dynamic factors and boundary conditions which influence the frequency of occurrence of pain and/or injuries which occur in the lower extremities as a result of playing the game of tennis. Two groups of factors were studied:​ the dynamics of the movement and the type of shoe worn (one type with low friction and one type with high friction properties). The method used was a prospective analysis, i.e., all information concerning the movement and boundary conditions was collected from healthy subjects at the beginning of the study. 229 subjects were recruited who then performed three types of test movements:​ running, running- stopping and hopping sideways. The kinematic and kinetic measurements of these movements were carried out with a Kistler force platform and a Locam II high-speed camera. The subjects then played tennis for a two to three month period (half of the group played with one type of shoe, the others played with the other shoe). After each playing session the subjects had to fill in a "game record" sheet where they recorded the boundary conditions of the game (e.g., type of surface, length of the game, etc.). After a certain period of time some players experienced pain and/or injuries. These players were instructed to make an appointment with a physician of the University of Calgary's health centre in order to get a medical assessment which was recorded on a " medical questionnaire." The biomechanical results of the measurements of the players with pain were then compared to the results of the subjects without pain. The results from the questionnaires showed that the players wearing the hard shoe with high friction were injured more frequently (47.1%) than the players wearing the soft shoe with low friction (32.6%). The site of pain was connected with the type of shoe worn, and the frequency of pain could be related to the type (competitive- recreational) and the duration of the game. The biomechanical analysis resulted in consistent findings for the three movements studied. All movements had variables which showed significant differences for the pain and the no pain groups. The main findings were:​

The type of tennis shoe influences the type and magnitude of the stresses exerted on the lower extremities. The results suggest the assumption that the type of shoe is connected with the occurrence of pain and injuries. The behaviour of subjects in fast sideways movements with sudden changes in direction seem to be related to the occurrence of pain. It was found that the amount of inversion of the foot in this sideways movement was significantly different for subjects with pain compared to subjects without pain. A two dimensional analytical model of the foot was developed in order to explain the experimental result.

The results suggest that a prospective biomechanical analysis of typical movements can be used to establish assumptions concerning the etiology of pain and injuries in sports related activities.