STUDY DESIGN: Phenomenographic, cross-sectional. OBJECTIVES: To describe ways of experiencing participation in activities of individuals with a nonreconstructed anterior cruciate ligament injury and to describe the emotional aspects related to participation. Further, the objective was to explore factors affecting the activity level. BACKGROUND: The importance of assessing different factors (knee status, muscle performance, psychological factors, performance-based tests, and subjective rating of knee function) after an anterior cruciate ligament injury has been emphasized. However, the results of these assessments do not answer the question of how the individuals themselves experience their participation in activities. METHODS: Semi-structured interviews were conducted with 19 strategically selected informants (age range, 18-43 years) who had sustained an anterior cruciate ligament injury 18 to 67 months previously. A phenomenographic approach, which describes individuals' ways of experiencing a phenomenon, was used. RESULTS: Five qualitatively different categories were identified: (A) unconditioned participation, (B) participation as conditioned by risk appraisal, (C) participation as conditioned by experienced control of the knee, (D) participation as conditioned by experienced knee impairment, and (E) participation as conditioned by neglecting the knee injury. Within each category, 5 interrelated aspects were discerned: focus, level of performance, activities, strategies, and feelings. Categories A, C, and E reflected experiences of full participation, whereas categories B and D reflected experiences of modified participation. There were mostly positive feelings regarding participation. Negative feelings were expressed in category D. Factors affecting the activity level were grouped according to the framework of the International Classification of Functioning, Disability and Health and described as facilitating or hindering the activity level. Facilitating factors included regaining and maintaining physical function, regaining confidence in knee function, and learning/relearning movement patterns. Hindering factors included fear of injury/reinjury, uncontrollable giving way, and loss of motivation. CONCLUSION: With different strategies, most of the informants achieved a satisfactory activity level, despite impairments and decreased activity level. Both physical and psychological factors were described to affect the activity level, as well as time since injury.