Class: BE209
Group: R1
Members: ANGGONO,DANIEL;CHAU, TUNG T;GOKHIN, DAVID; KEANE, MEGAN
P;NGUYEN DUC, THANH TRAN; PLEVY, JAMIE
Date: December, 2002
INTRODUCTION:
The objective of the project was to recreate the effect of LegStrength.vi,
but this time without the aid of any special virtual instruments.
Namely, a circuit was built that functioned as a window comparator and
then it was used to measure the number of times that an exercise device
attached to an individual’s arm moved through its range of motion in a
fixed amount of time. The variables that were measured are the effect
of exercise before arm extension and the effect of dominant vs. non-dominant
sides (namely, right vs. left hands in a right-handed individual).
Specifically, two hypotheses were tested: (1) It is expected that the number
of full arm extensions through the voltage “window” in 1 minute will increase
immediately after exercise has been done with an added weight. The
null hypothesis is: “There is no difference in the number of arm extensions
before and after exercise is done with an added weight.” (2) It is
expected that the number of full arm extensions through the voltage “window”
in 1 minute will be higher on the dominant side. The null hypothesis
is: “There is no difference in amount of work performed by the arm in 1
minute between the dominant and non-dominant sides.”
When a voltage comparator was first utilized in Experiment 3, it was observed that the software called LegStrength.vi caused an LED to light whenever the voltage across a potentiometer was between two specified input voltages, namely a high reference voltage and a low reference voltage. Such a device is known as a window comparator, because it responds to voltages within a predefined range, or “window.” Window comparators are useful in any situation such that a voltage being monitored must remain within predefined limits. For example, it may be crucial that a temperature remain within an interval conducive for the growth of tissue culture, or that the brightness of a reading lamp is high enough to be useful but not so high as to be a nuisance. In the situation being investigated in this lab, the window comparator was used to monitor the movement of an exercise device as the arm is extended through its range of motion. The start- and endpoints of the motion corresponded to the boundaries of the voltage window. With a device that can indicate a range of motion, it was also be possible to study the effect of exhaustion and side-dominance on performance.
This exercise device is similar to a range-of-motion goniometer which
alerts the user with an LED when the proscribed boundaries of motion are
reached. These devices are commonly used in physical therapy and
rehabilitation. They also have applications in athletic training
and performance assessment. For example, the Guymon Goniometer eliminates
the need to manually store each measurement collected by the device. By
storing the information internally, it reduces evaluation time. Scores
can be recalled later or can be loaded directly into a computer through
the use of serial port computer interface and software. Also,
the Universal Inclinometer is comparable to the goniometer for quick and
easy upper and lower extremity range of motion measurements because it
is easily adjusted at the initial position so the final reading is the
range of motion.