FIXED MYOMETRY  

A FIXED MYOMETRY system normally consists of an electric HIGH/low examination table, an  orthopedic frame, pc or notebook computer with the QMA program, an analog/digital acquisition device, and various input instruments.  The examination table is placed within and surrounded by the orthopedic frame, or within easy access to a WALLSLIDE fixed point. 
An in-line force transducer (load cell) is secured to the frame, and a strap or cable is extended to a cuff.  The cuff is worn by the patient (subject), and the the patient is positioned on the examination table in such a way as to isolate a muscle or muscle group to test.   The test is started, the patient is directed to exert effort, and the resultant data is displayed as a trace (force/time curve).   The analog signal received from the force transducer is digitized by the acquisition converter in the pc and converted to data within a usable file structure.  Over time additional data may be acquired for longitudinal comparative analysis.  Progress of the patient may be fully documented with   reports that are automatically generated from the information you request.
Fixed Myometry testing permits stronger extremities, that may exceed 200 lbf, to be assessed without compromise.  Mechanical compromises of testing may occur when the effort exceeds either the maximum capacity of the instrument, or the effort permits the fixed point (plane of resistance) to be moved.  Another mechanical compromise of testing may occur when the effort is small, and the upper capacity of the instrument large.  The maximum error (accuracy) of the instrument may exceed the effort measured.  It is recommended to utilize instruments (force transducer) that compliment (slightly exceed) the anticipated efforts of the patient.  Instruments are normally ailable in a range from 1.1 lbf to 1000 lbf.

Critical criteria for test validity is that the acquisition of the data be accurate and repeatable.   Accuracy of an input instrument may be easily confirmed or improved with "Check & Tweak" - a sub-routine within QMA.  Repeatability or inter-rater reliability may be improved when each member of a study group is trained and utilize the same techniques and methodology when testing a patient.