# Full body Inverse dynamics analysis

## Disciplines

Biomechanics and Biotransport

## Abstract (300 words maximum)

In biomechanics when trying to create an in-depth analysis of the forces on the body, it is common to use the inverse dynamics method as a form of calculation. The inverse dynamics of the human body are calculated by using newton’s laws. With the human body it is necessary to use multiple axis systems, a global axis that is a fixed origin point and x,y,z axes at the center of mass of each portion of the body. The reaction forces and moments must be transformed from the origin axis to each specific section. This is achieved by using several matrix equations. These transferred moments and reactions are then used to calculate angular acceleration and angular velocity by using Euler’s equations. This process of transforming axes and solving many equations must be done for each joint section of the body. The typical model of the human body has at least twelve of these joint sections. By utilizing MATLAB, a software that is used for complex calculations and OpenSim a modeling software for the human body this process can be simplified. In OpenSim motion capture data can be uploaded into the program and assigned to various models of the human body. The motion capture data is gathered by placing markers on a human subject and using high speed cameras to capture movement. By creating an interface between MATLAB and OpenSim it is possible to create a system that simplifies the process of calculating inverse dynamics from motion capture data. This interface is paired with MATLAB code to create a full body analysis of inverse dynamics from motion capture data.

## Academic department under which the project should be listed

WCHHS - Health Promotion and Physical Education

## Primary Investigator (PI) Name

Michael Hales

## Additional Faculty

John Johnson, jjohn235@kennesaw.edu, Department of Exercise Science and Sport Management

Full body Inverse dynamics analysis

In biomechanics when trying to create an in-depth analysis of the forces on the body, it is common to use the inverse dynamics method as a form of calculation. The inverse dynamics of the human body are calculated by using newton’s laws. With the human body it is necessary to use multiple axis systems, a global axis that is a fixed origin point and x,y,z axes at the center of mass of each portion of the body. The reaction forces and moments must be transformed from the origin axis to each specific section. This is achieved by using several matrix equations. These transferred moments and reactions are then used to calculate angular acceleration and angular velocity by using Euler’s equations. This process of transforming axes and solving many equations must be done for each joint section of the body. The typical model of the human body has at least twelve of these joint sections. By utilizing MATLAB, a software that is used for complex calculations and OpenSim a modeling software for the human body this process can be simplified. In OpenSim motion capture data can be uploaded into the program and assigned to various models of the human body. The motion capture data is gathered by placing markers on a human subject and using high speed cameras to capture movement. By creating an interface between MATLAB and OpenSim it is possible to create a system that simplifies the process of calculating inverse dynamics from motion capture data. This interface is paired with MATLAB code to create a full body analysis of inverse dynamics from motion capture data.