Validity and Reliability of a Digital Inclinometer to Assess Knee Joint Position Sense in an Open Kinetic Chain.

CONTEXT New methods are being validated to easily evaluate the knee joint position sense (JPS) due to its role in sports movement and the risk of injury. However, no studies to date have considered the open kinetic chain (OKC) technique, despite the biomechanical differences compared to closed kinetic chain movements. OBJECTIVE To analyze the validity and reliability of a digital inclinometer to measure the knee JPS in the OKC movement. DESIGN The validity, inter-tester and intra-tester reliability of a digital inclinometer for measuring knee JPS were evaluated. SETTING Sports research laboratory. PARTICIPANTS Eighteen athletes (11 males and 7 females; 28.4 ± 6.6 years; 71.9 ± 14.0 kg; 1.77 ± 0.09 m; 22.8 ± 3.2 kg/m2) voluntary participated in this study. MAIN OUTCOMES MEASURES Absolute angular error (AAE), relative angular error (RAE) and variable angular error (VAE) of knee JPS in an OKC. RESULTS Intraclass correlation coefficient (ICC) and standard error of the mean (SEM) were calculated to determine the validity and reliability of the inclinometer. Data showed excellent validity of the inclinometer to obtain proprioceptive errors compared to the video analysis in JPS tasks (AAE: ICC = 0.981, SEM = 0.08; RAE: ICC = 0.974, SEM = 0.12; VAE: ICC = 0.973, SEM = 0.07). Inter-tester reliability was also excellent for all the proprioceptive errors (AAE: ICC = 0.967, SEM = 0.04; RAE: ICC = 0.974, SEM = 0.03; VAE: ICC = 0.939, SEM = 0.08). Similar results were obtained for intra-tester reliability (AAE: ICC = 0.861, SEM = 0.1; RAE: ICC = 0.894, SEM = 0.1; VAE: ICC = 0.700, SEM = 0.2). CONCLUSIONS The digital inclinometer is a valid and reliable method to assess the knee JPS in OKC. Sport professionals may evaluate the knee JPS to monitor its deterioration during training or improvements throughout the rehabilitation process.