Expert-novice Differences in SMR Activity during Dart Throw
Ming-Yang Cheng, Li-Chuan Lo, Chung-Ju Huang, Tsung Min Hung
The mental state prior to execution has a
major influence on the performance,
especially in self-paced sports (Salazar et al.,
1990; Zinsser, Bunker & Williams, 2006).
14 Elite
players
60 dart throw
tests in 6
sessions. Each
section included
10 dart throws
Mental
state
15
Novices
EEG data
acquiring
Attention
Performance
Attention is the key
element of mental
state related to peak
performance
(Krane & Williams,
2006; Vietta, Peper,
Schmid, 2006)
■ Rationale:
The application of EEG to examine motor
behavior provides a high-resolution metric to
capture the temporal dynamics of regional
cerebral cortical activity related to performance
(Hung, 2008). Recent studies addressed some
EEG attention indicators related to optimal
precision sports performance prior to execution,
however, there were few studies on the
relationship between SMR activity and
precision sports performance.
.
■ SMR (Sensory motor rhythm)
1. 12-15 Hz rhythm in sensory motor cortex,
which activity is negatively related to the
activity of sensory motor cortex (Sterman,
1996).
2. Higher SMR activity is associated with
reducing the somatosensory interference to
maintain the perception and attention during
information processing under preparation
state (Vernon et al., 2003), and action
inhibition, relaxed attention focusing, large
working memory (Gruzelier, Egner, &
Vernon, 2006).
■ Hypothesis:
Dart throw experts closer to throwing have
higher SMR power than novice.
SMR: The mean power value of C3
and C4 with a frequency of 12-15 Hz.
Action detection: bipolar was set in
the interior of the right-hand forearm.
Sample data: 3000ms prior to
execution.
2 (GROUP) x 3 (TIME) two-way
ANOVA mixed design, α = .05.
■ No interactions (F = 2.841, p = 0.087, eta
squre = 0.11) was found. However, the
GROUP main effect was significantly
different (F = 107. 65, p < .05, eta square =
0.82). The mean SMR power for experts 3s
before the dart throw was significantly
higher than novice and was maintained
stably higher. There was no difference in the
main effect of time (Figure 1).
Group
T3
T2
T1
Mean
Expert 0.53 (0.29) 0.58 (0.30) 0.60 (0.44) 0.57*
Novice
Mean
-0.57 (0.23) -0.64 (0.21) -0.65 (0.21)
-0.02
0.26
-0.43
-0.03
Table 1 Mean SMR power (μV) for expert and novice
during preparation of dart throw.
■ Purpose: To test whether the 12-15 Hz
EEG power only occurred in the sensory
motor cortex but not in the other regions.
■ Hypothesis: The mean power with 12-15
Hz for last 3s prior to execution in frontal
lobe, parietal lobe and occipital lobe had
no difference.
■ Statistics: 2 (GROUP) x 3 (TIME) twoway ANOVAs mixed design were applied
to test the difference in power with 12-15
Hz in all regions.
■ Result: No interaction result for group
and time factors. However, group main
effects was significant in all regions.
SMR power maintain a higher trend for
expert than novice during preparation
before dart throwing.
Figure 1 Mean SMR power (μV) for expert and
novice during preparation of dart throw.
■ SMR power before execution: Experts >
Novices
1. Experts’ skill level had achieved automaticity,
thus their performance didn’t rely on the
feedback of external kinesthesis information.
2. The enhancement of SMR power was related
to the improvement of attention (Egner, 2004).
Experts before execution might maintain their
attention under higher level.
■ Control analysis: the higher mean power of
12-15 Hz is not restricted to sensory motor
area.
1. The result of cerebral activity changing among
multi-regions has been confirmed by previous
study (Egner, 2004). Thus, attention
enhancement is not only due to promoting
power of 12-15 Hz in sensory motor area, but
a result of multi-regions’ interaction.
2. EEG power with 12-15 Hz belonged to β1 and
higher β1 represented the vigilance attention
of general awake (Steriade, 1993). Thus,
experts they were probably under general
awake state and maintained optimal attention
focusing before action execution.
Sport and Exercise Psychophysiology Lab., National Taiwan Normal University, Taiwan