Biofeedback
is
a form of self-regulation in which an individual is provided information in the
form of sensory feedback about a biological condition or function in order to
gain control over that biological function. Biofeedback is often used as a
therapeutic tool by which sports medicine/rehabilitation professionals,
neurophysiologists, psychophysiologists, and therapists can use
electrophysiological instrumentation to measure, process, and “feedback” the
recorded information to the participating athlete or subject. The feedback is
usually provided through auditory and/or visual means.
There
are many types of biofeedback modalities available. One of the most popular and
widely accepted modalities is surface
EMG biofeedback. EMG (electromyography) bioinstrumentation measures
muscle activity by recording electrochemical activity of a muscle occurring
during depolarization and recruitment of a skeletal muscle motor unit. This
modality is used for muscle
reeducation and control when
orthopedic injuries or surgeries have taken place, or when the peripheral
nervous system has been impaired. It is also used to promote muscle relaxation
to decrease muscle guarding, pain, stress, and anxiety.
A
simple muscular biofeedback experiment design might use surface EMG electrodes
placed over the Vastus Medialis and Vastus Lateralis muscles. Surface EMG
electrodes should be placed vertically (parallel to the muscle fibers), over the
muscle belly, or largest part of the muscle, and a ground electrode should also
be used. Surface EMG should be recorded in several trials, including a Baseline
without biofeedback (where the participant is asked to maximally relax, e.g.,
not contract), Maximal Contraction
without Biofeedback, and a variety of Maximal Contraction with Biofeedback, such as
visual stimulus or auditory stimulus. After recording, compare the
surface EMG recordings and use peak-peak and mean measurements to determine if
any significant change was detected between any of the variables.
Biofeedback
is considered advantageous, as it provides participants a chance to use their
visual and auditory senses to become more aware of how they are performing
during therapy or training, attempt to improve upon it, and immediately see the
improvement as it is occurring. Because participants can immediately note
improvements, they are “rewarded.” This reward will hopefully lead to larger
improvements and accomplishments.
