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

Area of Science:

• Biomechanics
• Sports Science
• Human Movement Analysis

Background:

• Inverse dynamics is essential for calculating work output in biomechanical analyses.
• Accurate calculation of work output is critical for understanding athletic performance and injury mechanisms.
• Experimental errors can significantly impact the reliability of biomechanical calculations.

Purpose of the Study:

• To systematically evaluate the impact of experimental errors on work output calculations.
• To compare the sensitivity of the rotational and translational methods of inverse dynamics to simulated errors.
• To determine which inverse dynamics method provides more reliable work output data during vertical jumping.

Main Methods:

• A 2D musculoskeletal model generated precise kinematic data for vertical jumps.
• Simulated experimental errors by manipulating joint center (JC) and center of mass (CM) locations by +/-10%.
• Calculated work output using both conventional (rotational) and translational inverse dynamics methods with manipulated data.

Main Results:

• The translational method exhibited lower sensitivity to simulated errors in JC and CM, with up to 13% error in total work output.
• The rotational method showed higher sensitivity, with up to 28% error in total work output.
• The rotational method was particularly susceptible to simulated errors in joint center locations.

Conclusions:

• The translational method of inverse dynamics is more reliable for calculating work output in vertical jumping when experimental errors are present.
• Researchers should consider the translational method to enhance the accuracy and robustness of biomechanical analyses.
• Minimizing errors in joint center and center of mass identification is crucial for accurate biomechanical modeling.