Reliability, precision, and gender differences in knee internal/external rotation proprioception measurements

Objective: To develop and assess the reliability and precision of knee internal/external rotation (IR/ER) threshold to detect passive motion (TTDPM) and determine if gender differences exist. Design: Test-retest for the reliability/precision and cross-sectional for gender comparisons. Setting: University neuromuscular and human performance research laboratory. Participants: Ten subjects for the reliability and precision aim. Twenty subjects (10 males and 10 females) for gender comparisons. Intervention: All TTDPM tests were performed using a multi-mode dynamometer. Subjects performed TTDPM at two knee positions (near IR or ER end-range). Intraclass correlation coefficient (ICC (3,k)) and standard error of measurement (SEM) were used to evaluate the reliability and precision. Independent t-tests were used to compare genders. Main outcome measurements: TTDPM toward IR and ER at two knee positions. Results: Intrasession and intersession reliability and precision were good (ICC = 0.68-0.86; SEM = 0.22°-0.37°). Females had significantly diminished TTDPM toward IR at IR-test position (males: 0.77° ± 0.14°, females: 1.18° ± 0.46°, p= 0.021) and TTDPM toward IR at the ER-test position (males: 0.87° ± 0.13°, females: 1.36° ± 0.58°, p= 0.026). No other significant gender differences were found (p> 0.05). Conclusions: The current IR/ER TTDPM methods are reliable and accurate for the test-retest or cross-section research design. Gender differences were found toward IR where the ACL acts as the secondary restraint.