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
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
