Brief Review

This module focuses on Bioinstrumentation. In this section, a brief review of an approach to the measurement of human performance is presented. Click here for some stories and examples of where quantitative measurements are preferred to qualitative evaluations of human performance.

In order to study the motion of a joint and determine the strength of a muscle group, we need the following:

1. Create a model of the body segments of interest. (Click here for an example.) The figure below is a possible representation of the upper extremity. This is a three-link model with Links L1, L2 and L3 representing the upper arm, forearm and hand respectively. Joints J1, J2 and J3 are the shoulder, elbow and wrist. The centers of mass for each link are cm1, cm2 and cm3. Note: The center of masses are not at the midpoints.
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3. Derive the Equations of Motion (EOM). If reaction forces within intermediate joints are required, a Newtonian approach may be preferable. A Lagrangian approach is generally preferable for multidegree of freedom systems.
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5. Determine the Anthropometic data.
6. Kinematics - Develop a method to measure joint displacements, velocities, or accelerations. A table is provided to help organize the calculations of the velocities and accelerations.
7. Kinetics - Develop a method to measure applied loads and corresponding moment arms.
8. Design the Clinical Study (elements of this task were performed before Step 1 and in parallel to all other steps).
9. Design the instrumentation. Determine the sensors, sampling rates and filters.
10. Conduct limited test
11. Test normals
12. Test patients/subjects
13. Analyze data
14. Modify above steps as necessary.

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