Maximum hand grip protocol serves for acquiring and computing the average maximum value of force that subject is able to apply by squeezing the provided force measurement device. Later the computed average maximum value is passed to global variable in order to be used in other protocol routines described in parallel subsections of this document.
The source code of this program is located in physRunHandgripMax.m file. In this function we are aiming to get three separate measurement of hand grip force and compute the average.The algorithm of implementation consists of initialization, acquisition and computation phases.
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- Receives the protocol setting and analog/digital channel settings.
- Creates analog channel object handle to read the amount of hand gripe force from BIOPAC acquisition unit.
- Creates digital channel object handle to read the 0-7 button press event.
- Creates figure on the extended screen with given coordinates.
- Creates axes, level indication bar that indicates to the amount of hand grip force.
- Creates labels "MAX Force1=","MAX Force2=","MAX Force3=" indicating maximum acquired value of hand grip force during measurement-1, measurement-2, measurement-3 respectively.
- Creates indicator in the upper right corner indicating the currently ongoing measurement number.
- Extracts the calibration parameters from received channel settings object.
- Outputs the analog signal to BIOPAC protocol channel, with voltage level corresponding to "Hand Grip MAX" protocol.
Acquisition
In this phase function physRunHandgripMax looks for the maximum value of hang grip that has been acquired during n-th measurement. As subject applies a force the program monitors and stores the maximum value that have been acquired in variable HANDMAX_TMP(n), which is displayed in real time on the screen. Subject can continue applying force but new value will be accepted only if it is greater than previously recorded force value during the same measurement. To proceed to next measurement any of 0-7 buttons shall be pressed.
Computation
After acquiring all the necessary samples of maximum hand grip force the program computes the average using sample mean formula. The computed average value is passed to global variable HANDGRIP_MAX. This average maximum force value is also displayed on the screen during all n measurements.