Twenty-two patients with Grade III acromioclavicular (AC) joint dislocations were treated nonoperatively and evaluated by questionnaire, physical exam, and isokinetic strength and endurance testing. The mean follow-up time was 2.6 years (range, six months to 7.7 years). Patients returned to work an average of 2.1 weeks after injury. All of the patients were right-handed; 14 injured their dominant right AC joint whereas eight injured their nondominant left side. Isokinetic muscle testing was used to evaluate the strength and endurance of both shoulders in all 22 patients. Strength was measured as peak torque for shoulder flexion, extension, internal and external rotation, abduction, and adduction at 400 degrees per second. Internal and external rotation testing was also evaluated at 60 degrees per second. Endurance was measured at 400 degrees per second for flexion, extension, and internal and external rotation. The strength and endurance levels of the injured shoulders were comparable to the noninjured side. Although discomfort levels were low, long range follow-up reports reveal discomfort appearing with increased intensity of activity.