[The influence of psychological variables on sports performance: assessment with the Questionnaire of Sports Performance-related Psychological Characteristics].

The purpose of this research was to observe the relationship among psychological variables and three important issues in sports competition: achieving success, long-term continuance and sustaining injuries. Three studies were carried out with three groups of athletes from the areas of judo, football and swimming, using the Questionnaire of Sports Performance-related Psychological Characteristics as the measuring instrument. The analyses carried out revealed significantly statistical associations between the perception of stress control and of self-confidence, and between achieving success, long-term continuance in competition sports and sustaining injuries. These results indicate the importance of psychological skills training to aid sports performance and prevent injuries, as well as the use of the above-mentioned questionnaire, which, with a limited number of items, measures a wide range of psychological variables in the specific context of sports.