CONTEXT: Quadriceps strength is a key outcome for guiding rehabilitation and return to sport-specific activities after anterior cruciate ligament reconstruction (ACLR) surgery. OBJECTIVE: (1) Describe the quadriceps-strength-testing practices and barriers college athletic trainers (ATs) are using and experiencing when returning patients to sport-specific activities after ACLR. (2) Compare testing methods between college ATs working in the National Collegiate Athletic Association (NCAA) Division I setting and other college settings. DESIGN: Cross-sectional study. SETTING: Online survey. PATIENTS OR OTHER PARTICIPANTS: Two hundred forty-three full-time collegiate ATs who had primarily overseen/directed an ACLR rehabilitation in the past 5 years (age = 34.8 ± 10.7 years, length of AT practice = 11.7 ± 9.3 years, NCAA Division I setting = 56%). MAIN OUTCOME MEASURE(S): Our survey included 4 sections: demographics, general ACLR rehabilitation practices, quadriceps-strength-testing methods and criteria, and quadriceps-strength-testing barriers. RESULTS: Knee-muscle strength was the most common (98%) outcome collegiate ATs used when determining whether an ACLR patient is ready to progress to sport-specific activities. Manual muscle testing was the most used testing method (57%), followed by isokinetic dynamometry (IKD) (48%), repetition maximum testing (35%) and handheld dynamometry (22%). Most ATs (63%-64%) used greater than 90% side-to-side symmetry as their return to sport-specific activities criterion. Lack of equipment needed (83%), lack of financial means (28%), and lack of training/education (20%) were the barriers that most limited ATs use of IKD testing, the gold standard testing method. Compared with ATs in other settings, a greater proportion of ATs working in the NCAA Division I setting used IKD testing (65% vs 28%) and a smaller proportion used manual muscle testing (47% vs 70%). CONCLUSIONS: Although almost all college ATs considered knee-muscle strength an important outcome to assess when returning patients to sport-specific activities after ACLR, quadriceps-strength-testing practices were highly variable among ATs and may be affected by access to necessary resources.