Background:The traditional index of return to sport (RTS) readiness following anterior cruciate ligament reconstruction (ACLR) is the achievement of physical competence criteria. Emerging research indicates that psychological response and self-perceptions of physical competence may be critical for successful RTS among young athletes.Hypothesis/Purpose:The purpose of this study was to test the hypothesis that young athletes with higher actual and perceived physical competence will demonstrate a more positive psychological response at time of RTS after ACLR.Methods:Thirty-eight athletes (median age=16.9 years [IQR: 16.1, 18.8]) following primary ACLR completed testing within 8 weeks of medical clearance to RTS. All participants completed isokinetic knee extension strength (180°/s) and single-limb crossover hop for distance, in addition to the Knee injury and Osteoarthritis Outcome Score (KOOS), Self-Perception Profile Athletic Competence, and ACL Return to Sport after Injury (ACL-RSI) questionnaires. Criteria for the achievement of actual (APC) and perceived physical competence (PPC) were operationally defined based on established age- and activity-relevant cutoff scores (Table 1). Psychological response was assessed with ACL-RSI overall score, in addition to each ACL-RSI subscale score (Emotions, Confidence, Risk Appraisal). Multiple linear regression analyses were used to determine differences in ACL-RSI scores based on achievement of APC and PPC, while adjusting for age and sex.Results:Of the 38 participants, 9 (23.7%) were able to meet all criteria for High APC, while 29 (76.3%) participants were categorized as Low APC. Twenty-one (55.3%) of the 38 participants were categorized as Very Good PPC, and 17 (44.7%) were categorized as Somewhat Good PPC. The regression model for overall ACL-RSI score was significant (F (4,33) = 5.224, p=0.002, adj. R2 = 0.313), with age explaining 26.4% of the total variance (p=0.001). In evaluating the ACL-RSI subscales, the regression model for the ACL-RSI Emotions score was significant (F(4,33) = 7.760, p<0.001, adj. R2 = 0.422), with age, sex, and PPC explaining 33.9% (p<0.001), 7.0% (p=0.04), and 7.7% (p=0.03) of the total variance, respectively. Lastly, the regression model for ACL-RSI Risk Appraisal score (F(4,33) = 3.416, p=0.019, adj. R2 = 0.207) was significant, with age and PPC explaining 10.5% (p=0.034) and 12.9% (p=0.02) of the total variance, respectively (Table 2).Conclusion:In partial accordance with our hypothesis, higher PPC, but not APC, was significantly associated with a more positive psychological response among young athletes after ACLR. Interventions to improve self-perceptions of competence may optimize psychological readiness to RTS.Table 1.Actual and Perceived Physical Competence CriteriaTable 2.Results of Standard Multiple Regression of Competence on ACL-RSI Scores