%0 Journal Article %A King, Mark A. %A Lewis, M. G. C. %A Yeadon, M. R. %D 2012 %I Begell House %K computer simulation, joint torque, biarticular muscle, knee joint %N 2 %P 117-130 %R 10.1615/IntJMultCompEng.2011002379 %T IS IT NECESSARY TO INCLUDE BIARTICULAR EFFECTS WITHIN JOINT TORQUE REPRESENTATIONS OF KNEE FLEXION AND KNEE EXTENSION? %U https://www.dl.begellhouse.com/journals/61fd1b191cf7e96f,42f1beba0b405e70,28cd90e70c62e74d.html %V 10 %X The purpose of this study was to consider whether it is necessary for biarticular effects to be accounted for in subject-specific representations of maximal voluntary knee extension and knee flexion torques. Isovelocity and isometric knee torques were measured on a single participant at three different hip angles using a Contrex MJ dynamometer. Maximal voluntary torque was represented by a 19-parameter two-joint function of knee and hip joint angles and angular velocities with the parameters determined by minimizing a weighted rms difference between measured torques and the two-joint function. The weighted rms difference between the two-joint function and the measured knee flexion torques was 14 Nm or 9% of maximum torque, while for knee extension the difference was 26 Nm or 9% of maximum torque. The two-joint representation was shown to be more accurate than an existing single-joint representation for torques measured at hip angles other than those used to derive the single-joint function parameter values. The differences between the traditionally used single-joint representation and the measured knee flexion and knee extension torques were largest for the most extended hip joint angle (15 and 18% of maximum torque, respectively), while the corresponding differences for the two-joint function were 9% and 8% of maximum torque. It is concluded that a two-joint function can account for changes in knee flexion and knee extension joint torques due to both monoarticular and biarticular muscles over a range of both hip and knee angles, and this has the potential to improve the biofidelity of whole-body subject-specific torque-driven simulation models. %8 2012-03-13