Test–Retest Reliability of Lower Extremity Functional Tests after a Closed Kinetic Chain Isokinetic Testing Bout

Context: Athletes are often examined for return to sports using a functional-testing algorithm. No research has determined whether a closed kinetic chain (CKC) isokinetic testing bout influences the reliability of functional tests. Objective: To determine whether a concentric CKC isokinetic test bout alters test‐retest reliability of lower extremity functional testing. Design: Subjects participated in velocity-spectrum CKC isokinetic bouts on 2 days 1 week apart. Setting: Hospital-based clinic. Participants: 28 normal subjects (mean age 26.7 years, height 27.2 cm, weight 75.8 kg). Analysis and Results: Means and SDs were determined. Intraclass correlation coefficients were used to calculate test‐retest reliability and between days 1 and 2 ranged from .91 to .98. Conclusions: Even after a CKC isokinetic test bout, test‐retest reliability of functional tests is very high. Future research should determine test‐retest reliability of functional tests for patients with lower extremity pathology. Key Words: muscle strength, functional outcome measures, physical-performance tests Manske RC, Smith B, Wyatt F. Test‐retest reliability of lower extremity functional tests after a closed kinetic chain isokinetic testing bout. J Sport Rehabil. 2003;12:119-132. © 2003 Human Kinetics Publishers, Inc. Athletic trainers and sports physical therapists often treat patients after lower extremity injury or surgical intervention. The ultimate goal of rehabilitation is to return these individuals to full premorbid function in the most efficient manner. Clinicians should assess level of impairment with goniometric measurement of range of motion, manual muscle testing, ligament-laxity testing, girth measurements, and isokinetic testing. Although these measurements are crucial to determine the extent of remaining pathology, they do not always provide an indication of a patient’s true physical-functional capabilities. Various functional-performance tests have been developed in an attempt to more accurately quantify physical function. When attempting to quantify