A sensitivity analysis of the calculation of mechanical output through inverse dynamics: a computer simulation study

The purpose of this study was to systematically determine the effect of experimental errors on the work output calculated using two different methods of inverse dynamics during vertical jumping: (a) the conventional (rotational) method and (b) the translational method. A two-dimensional musculoskeletal model was used to generate precisely known kinematics. Next, the location of each joint center (JC) and the location of each segmentʹs center of mass (CM) were manipulated by ±10% of segment length to simulate errors in the location of joint centers (ΔJC) and errors in the location of segmentʹs center of mass (ΔCM), respectively. Work output was subsequently calculated by applying the two methods of inverse dynamics to the manipulated kinematic data. The results showed that the translational method of inverse dynamics was less sensitive (up to 13% error in total work output) to ΔJC and ΔCM than the rotational method (up to 28% error in total work output). The rotational method of inverse dynamics was particularly sensitive to simulated errors in JC.