Weng
(1987) recorded EEG 2-3 days prior to a marathon and one-half to three
and one-half hours following the marathon. He reported a reduction in
the power spectrum following the race especially in the total alpha band
indicating that distance running affects the CNS as well as muscular
and cardiopulmonary systems.
Twelve elite wrestlers had
occipital and precentral mean alpha frequency (MAF) recorded prior to
and following two training competitions (Weiss,Beyer &
Hanson,1991). MAF at the precentral site was increased in 20 of 24
sessions while at the occipital region MAF was increased in 22 of 24
sessions. This was viewed as a sign of higher CNS activation and
corresponded with previous reported results of increased MAF for the
"imagined' wrestling moves. The authors conclude that this concordance
would suggest that motor imagery may well be a good model for studying
activation processes in sport.
Imagery of the Event
There
is a recent review of the ample evidence of the changes in EEG during
the task of imaging motor skills but athletes were not used as
subjects. Jennerod (1994) reviews the neurophysiological studies of
movement imagery and suggest that when an individual is imaging
self-performed movements both the motor and visual-spatial systems of
the brain are involved.
DeBease (1989) used softball players
in an attempt to determine whether doing visual versus kinesthetic
imagery would result in different areas of the brain being utilized. She
found more alpha in the occipital region, the visual area, as compared
with the central or motor regions regardless of whether the athlete was
using the visual or kinesthetic perspective. .
Beyer,Weiss,Hansen,
Wolf and Seidel (1990) claim that the mean alpha frequency increased
over the left occipital and pre-central areas during imagery of a
swimming task. They used three imagery trials and found the second trial
to produce the larges increase in mean alpha frequency. They also
recommend the use of imagery to assess the mental processes in sport as
it seems to represent actual sport and has a minimum of artefacts.
Wilson,
Bird, Schwartz & Williams (1994) used quantitative or Q EEG to
assess visual and kinesthetic imagery of a 100 metre race with elite
swimmers. There were no differences in alpha between the two
perspectives but females had significantly more left temporal beta
while males had more right frontal beta during kinesthetic imagery.
This was interpreted as the utilizing of more thinking with language by
the females and more thinking with images by the males.
BIOFEEDBACK
The
use of EEG biofeedback to enhance motor skills of atypical patients has
been demonstrated in several studies (Birbaumer, 1997). Hemispheric
changes due to biofeedback of slow cortical potentials has been
demonstrated (Rockstroh, Elbert, Birbaumer & Lutzenberger, 1990).
From
the previous pre-performance EEG studies which showed hemispheric
asymmetries prior to the execution of a skill, Landers et al (1991)
used ERP biofeedback to determine if athletes could learn hemisphere
differentiation and whether this would affect sport performance.
Pre-elite but experienced archers were assigned to either a correct
(decrease left hemisphere activity), incorrect (decrease right
hemisphere) ERP's or to a control group. Slow potential shifts were
presented from the data of the few seconds prior to arrow release with a
visual bar display which also had computer controls for movement
artifacts. The archers had warm up trials followed by 27 data collection
trials with right and left temporal electrodes. There were no
differences between pre and post test performance scores for the control
group. The incorrect feedback group had poorer post-treatment scores
while the correct feedback group significantly improved their post
treatment archery scores.
A number of authors have reported
clinically using EEG biofeedback for enhancing sport performance but
none were located in the research literature. Additionally, these
studies reported at conferences included other mental training skills
that are known to have an impact upon sport performance, eg imagery,
relaxation, etc, so the contribution of EEG biofeedback to the reported
athlete improvement can not be assessed.
Cautions
and Summary of Section
Much of the research reported here
should be considered preliminary as the methodology was not always
reported and the quality of the research could not be determined.
Additionally most studies had very few athletes and their selection was
not always described. The diversity of countries reporting sport EEG
research suggests that there is an interest and need for research into
the assessment and training of athletes.
Following are summary
statements of research previewed in this paper:
The
baseline EEG of athletes who perform well in the stress of competition
shows a higher percentage of time in alpha
The learning of
motor skills changes EEG patterns.
EEG alpha increased in left
frontal prior to successful performance when there is no
visual-perceptual processing required
EEG alpha increases
in both right and left temporal/central regions when the athlete is
responding to others actions or both hands are required
EEG
alpha increased when athletes moved from spread to selective attention
Low frequencies dominated the first second of the readiness period
while beta dominated the last second of the readiness period
ERP's of athletes showed a predominance of right hemisphere activity
Different ERP measures distinguished the type of skill necessary for
different rifle shooting events
Frontal-central ERP negativity
is related to aiming in shooting tasks while slow wave positivity is
related to gun stabilization.
In recordings during competition,
higher frequency EEGs were recorded for the better athletes
Pre
to post sport performance shows enhanced alpha activity
Increases
in alpha are found in athletes who do sport skill imagery but only beta
was different when comparing visual vs kinesthetic imagery.
ERP
biofeedback was successfully learned by athletes and resulted in
improved sport performance
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Sue is a retired professor of York University, where she taught sport psychology, coaching, and self-regulation courses. Her experience includes Biofeedback and Neurofeedback in a medical center, counseling center, businesses, and in schools. For (
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