2
Work with EMG and relaxation and tension began during the
1920's and 1930's through the pioneering efforts of Edmund
Jacobson. Jacobson found that the more relaxed a muscle was, the
lower its EMG activity level was. He also noted that this lowered
EMG activity level was associated with a more general subjective
sense of relaxation.
EMG biofeedback is also being applied very successfully in
rehabilitation medicine - such as in regaining control of lost muscle
function, re-establishing the correct relationship between agonist
and antagonist muscles, relaxing spasmodic activity and in
strengthening weak or atrophied muscles.
While Jacobson's work marked a milestone in EMG research, his
methods of measuring EMG were crude and cumbersome by today's
standards. The MyoTrac represents a tremendous step forward in
EMG technology. Thanks to solid state electronics and micro
circuitry, equipment which used to fill a laboratory in Jacobson's
time can be replaced today by the MyoTrac - small enough to fit in
the palm of your hand.
Installing and Testing Your Battery
Battery Insertion
: We strongly recommend the use of an alkaline
or lithium 9 volt battery. You can use a rechargeable nickel-
cadmium (NiCad) battery, but keep in mind that although NiCad
batteries can be charged many times, they last only about one
quarter as long in operation as an alkaline battery.
To insert or remove the battery, hold the device in one hand and
firmly grasp the sides of the battery compartment lid with the other.
Pull straight towards the rear of the case to slide it off. (See Figure
1.) Replace the battery, being careful to observe the proper polarity.
Slide the lid back in place, pushing gently to snap the clip.
