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 exp erimental errors on the work output calculated using two different methods of inverse dynamics during vertical jumping: (a) the conventional (rotation al) method and (b) the translational method. A two-dimensional musculoskele tal model was used to generate precisely known kinematics. Next, the locati on of each joint center (JC) and the location of each segment's center of m ass (CM) were manipulated by +/- 10% of segment length to simulate errors i n the location of joint Centers (Delta JC) and errors in the location of se gment's center of mass (Delta CM), respectively. Work output was subsequent ly calculated by applying the two methods of inverse dynamics to the manipu lated kinematic data. The results showed that the translational method of i nverse dynamics was less sensitive (up to 13% error in total work output) t o Delta JC and ACM than the rotational method (up to 28% error in total wor k output). The rotational method of inverse dynamics was particularly sensi tive to simulated errors in JC. (C) 2000 Elsevier Science Ltd. All rights r eserved.