[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.