Japanese Psychological Research
2000, Volume 42, No. 3, 168–177
Disruption of kinematic coordination
in throwing under stress
TAKAHIRO HIGUCHI1
Department of Psychology, School of Arts and Letters, Tohoku University,
Kawauchi, Aoba-ku, Sendai 980-8576, Japan
Abstract: The present study tested the conscious-control theory of the relationship between
stress and performance. Performers under stress conditions consciously attempted to control
their movements, disrupting the automaticity of control. Twenty-two male subjects (11 in
Experiment 1 and 11 in Experiment 2) performed an underhand ball-throwing task using the
non-dominant hand. The inter-trial variability of two kinematic measures was analyzed, namely
arm-joint coordination during the throw and hand position at release (release point). Experiment 1
confirmed the validity of regarding these variability measures as indices of automaticity, as
they did not vary in spite of resource shortage induced by a dual-task paradigm. In Experiment 2,
in which stress led to a detriment in performance, the variability of joint coordination increased,
whereas the release point became more fixed. These findings imply that throwing performance is impaired when the coordination is disrupted as a result of inflexible movement
executed by conscious control.
Key words: stress, underhand throwing, automaticity, variability, joint coordination.
Many studies have examined how stress or
anxiety affects motor performance. A major
theory proposed by early researchers was the
inverted-U hypothesis, which was based on the
general arousal concept. However, it has been
criticized from various viewpoints, for example
the failure to explain the mechanism, the lack
of clear empirical support, and the face validity
of the curve shape (see Jones, 1995; Neiss, 1988,
for reviews).
An appealing alternative theory is the
conscious-control theory (Baumeister, 1984;
Hardy, Mullen, & Jones, 1996; Masters, 1992;
Willingham, 1998), which proposes that performers under stressful conditions are motivated
to perform well and attempt to control movements consciously using explicit knowledge.
Performance is impaired because this leads
to “deautomatization” (Deikman, 1969), that is,
disruption of learned automaticity of control,
and regression to earlier stages of learning. For
example, Masters (1992) demonstrated that
stress impaired golf putting performance only
when subjects had explicit knowledge of the
skill.
However, findings in support of the
conscious-control theory can also be explained
by the resource-shortage theory (Easterbrook,
1959; Eysenck, 1979, 1982; Humphreys &
Revelle, 1984; Wine, 1971). This proposes
1
I would like to thank Associate Professor Jiro Gyoba for his constructive comments on an earlier version of the
manuscript. I would also want to thank Associate Professor Kohki Kudo for his suggestions on improving the
experimental design. Reprints may be obtained from Takahiro Higuchi, Department of Psychology, School of Arts and
Letters, Tohoku University, Kawauchi, Aoba-ku, Sendai, 980-8576 (E-mail: [email protected]).
© 2000 Japanese Psychological Association. Published by Blackwell Publishers Ltd, 108 Cowley Road,
Oxford OX4 1JF, UK and 350 Main Street, Malden, MA 02148, USA.
Disruption of kinematic coordination in throwing under stress
that stress impairs the quality of performance
because task-irrelevant information competes
with task-relevant information for space in the
processing system (Eysenck, 1982, p. 99). This
proposition seems plausible, and is supported
by many empirical data (e.g., Darke, 1988;
Leon, 1989; MacLeod & Mathews, 1988;
Rapee, 1993; Sorg & Whitney, 1992). Based on
this theory, poor performance is not brought
about by deautomatization, because automaticity
requires few, if any, resources. For example,
Masters’ (1992) subjects, who had explicit knowledge, performed poorly because they could
not effectively execute conscious control, owing
to the resource shortage.
The present study tested the critical prediction of the conscious-control theory. It
examined whether stress impairs automaticity,
thus leading to poor performance. The problem
here is the difficulty of identifying behavioral
indications of automaticity. One index might be
movement variability. It has been widely accepted that, at least in early stages of learning,
skilled movements that involve automaticity
are highly stable (e.g., Lee & Swinnen, 1993;
Logan, 1985; Platz, Dentzler, Kaden, &
Mauritz, 1994; see Vereijken, van Emmerik,
Whiting, & Newell, 1992, for evidence). Thus it
is expected that automaticity can be measured
using movement variability. The validity of this
idea was examined in Experiment 1.
The experimental task in the present study
was underhand ball throwing with the nondominant arm, while aiming at a target. Automaticity was represented by the variabilities,
that is standard deviations, of two kinematic
measures: joint coordination during the forward
arm swing, and hand position at the moment
the ball was released, termed the release point.
Joint coordination was selected because it has
a high degree of freedom in natural throwing
(Hore, Watts, & Tweed, 1994). It is assumed
that, owing to automatization, joint coordination
becomes stable as consistent performance is
achieved through practice, and therefore the
variability of joint coordination will decrease
(McDonald, van Emmerik, & Newell, 1989;
Vereijken et al., 1992). The release point is
another important factor influencing the accuracy
169
of ball direction and is itself determined by
joint coordination (e.g., Hore, Watts, Martin, &
Miller, 1995; van Rossum & Bootsma, 1989).
Thus it should also show lower variability after
practice.
The present study comprised two experiments. The purpose of Experiment 1 was to
confirm the usefulness of movement variability
as an index of automaticity. If the variability is
determined by the degree of automaticity, it
should not increase in the case of resource
shortage for motor control because automatic
movements require few, if any, resources. A
dual-task paradigm was used to create the
resource shortage. In Experiment 2, the effect
of stress on movement variability was examined. Participants performed the throwing task
under stressful circumstances, in which anxiety
concerning poor performance was induced by
instruction.
General method
Task and apparatus. The experimental task was
an underhand ball-throwing maneuver using
the non-dominant hand, with the subject aiming at a target. All the subjects were righthanded. It should be noted that the degree of
freedom is constrained only in the early stages
of learning: In later stages it is freed to obtain
flexible movement (see Newell & McDonald,
1994; Vereijken et al., 1992). The non-dominant
hand was therefore chosen, so that low movement variability would represent high degree
of automaticity. In order for subjects to acquire
the skill quickly, the relatively simple underhand
ball throw was used in preference to more complex types of throwing skills, such as overhand
throwing or free throwing as in basketball.
The subjects threw tennis balls. The target,
composed of four concentric circles, was fixed
on a wooden board (100 cm × 100 cm). The
diameter of the inner circle (the bull’s-eye, at
which the subject aimed) was 8 cm and the
diameters of the other circles increased by
16-cm intervals. The board was placed so that
the bull’s-eye was at a height of 1 m and at a
distance of 3.3 m from the subject. Two LEDs
were placed over the target in order to pace the
© Japanese Psychological Association 2000.
170
T. Higuchi
throwing task. A red LED that was activated
for 1.5 s alerted the subjects to prepare for a
trial, and it was followed by a green LED that
signaled the start of the trial. Activation of
both LEDs was accompanied by audible beeps.
The displacement of the arm joints was
recorded with a Hi-8 video-camera (SONY,
Tokyo, Japan), which was placed 3 m to the left
of the subject and at a height of 1 m. The target
was filmed with a 8-mm video-camera (SANYO,
Tokyo, Japan) placed behind the subject, to
ascertain subjects’ performance.
To identify the frame in which the ball was
released, a small piece of folded plastic (3 cm ×
1 cm) was placed at the middle phalangial
joint of the middle finger. Copper plates were
attached to the inner sides of the fold. When a
tennis ball was being held, the copper plates
touched each other, and the electrical circuit
was completed. This activated an LED located
behind the subject’s head, and this was also
monitored by the camera monitoring the arm
movement. The frame in which the LED was
deactivated indicated ball release.
Procedure. LEDs were attached to the
shoulder, elbow, wrist, hand and hip, at specific
anatomical locations: the acromion process,
lateral epicondyle, radius styloid process, index
ungual phalange, and iliac crest, respectively.
These were used to calculate joint angles.
The subjects were instructed to aim and
throw the ball at the bull’s-eye, as accurately as
possible. Subjects performed the throwing task
in two sessions: a practice session and a performance session. The practice session consisted of
5 blocks of 30 trials, with 3–5-min rest between
the blocks.2 The performance session, which
consisted of a single block of 30 trials, was a
dual-task session in Experiment 1 and a stress
session in Experiment 2.
2
The amount of practice was determined in a pilot experiment, with a criterion that it was enough to decrease
the variability of joint coordination. Four male subjects
performed 300 throws on two consecutive days (150
throws each day). The procedure was the same as in
Experiments 1 and 2. The variability decreased up to
around 150 throws, but then remained more or less
constant, although this was not tested statistically.
© Japanese Psychological Association 2000.
Data analysis. Data were collected for
only the first and last 10 trials of the practice
session, together with the first 10 trials of the
performance session. The practice-session
trials were called the pre-practice session,
the post-practice session, respectively. The
kinematic data were sampled for 3 s. The
displacement of LEDs was digitized at a
sampling frequency of 60 Hz and processed via
a two-dimensional movement-recording system
(Quick-MAG system 1, OKK Inc., Tokyo,
Japan). Van Rossum and Bootsma (1989)
reported that the arm movement in underhand
throwing was executed mainly in the sagittal
plane. Therefore, two-dimensional recording
was sufficient for accurate analyses. After
transfer to the life-size unit, these data were
filtered by using a Butterworth lowpass filter.
The filtered frequency was 2.4–4.8 Hz, which
was determined by Hinrichs’ (1982) technique.
Performance was evaluated in terms of
absolute error (AE) and variable error (VE).
The AE was the mean absolute distance from
the bull’s-eye to the point of ball impact. The
VE was the standard deviation of the AE (see
Schmidt, 1988, ch. 3).
The variability of joint coordination was
evaluated as the standard deviation of crosscorrelations with zero time delay between the
angles at the shoulder, elbow and wrist (see
McDonald et al., 1989; Vereijken et al., 1992).
Cross-correlations were calculated for both
angular displacements and angular velocities.
The cross-correlations range from 1 to –1. A
value close to ±1 means that changes in one
cross-correlated component are highly dependent on changes in the other, while a value close
to 0 means these components change independently. Cross-correlation analysis was performed
on the data for the angular displacement and
velocity during the forward arm swing, which
started at the end of the back swing (termed
takeback), and terminated at the moment the
ball was released (see Figure 1). Each joint
angle was defined as the angle between two
segments. The shoulder angle, for example, was
an angle between the trunk (from the hip LED
to the shoulder LED) and the upper arm (from
the shoulder LED to the elbow LED).
Disruption of kinematic coordination in throwing under stress
End of
takeback
Ball
release
200
–110
–300
190
50
dual-task paradigm, in which subjects performed the throwing task at the same time as a
memory task. The variability measures should
not change in the dual-task situation, despite a
worsening of performance, because, as Singer,
Lidor, and Cauraugh (1993) demonstrated, a
conscious strategy cannot be executed effectively when mental resources are allocated to
the processing of a secondary task.
Elbow
Shoulder
20
–200
200
100
Wrist
150
170
–150
0
1.5
0
Time (s)
1.5
Time (s)
Forward arm swing
A. Angular
displacement
Figure 1.
171
B. Angular
velocity
Representative time course of angular
displacement (A) and velocity (B) for a
throw in the post-practice session.
The variability of the release point was
represented by the standard deviation of the
horizontal and vertical positions of the hand
when the LED that indicated the ball release
was deactivated.
Experiment 1
The purpose of Experiment 1 was to examine
whether the degree of automaticity could be
measured using the variability of the kinematic
measures. If the variability is determined by the
degree of automaticity, it should not increase in
the case of resource shortage for motor control. In the present experiment, a situation of
resource shortage was artificially created by a
Method
Subjects. The subjects were 11 male volunteers,
ranging in age from 19 to 28 years. All were
right-handed.
Secondary task. The secondary task was to
memorize a random sequence of five one-digit
numbers (e.g., 5, 4, 7, 1, and 8), and to
reproduce the number sequence backward
immediately after the trial. The numbers were
randomly selected from numbers 1 to 9, with
a restriction that the same number did not
appear more than once in a sequence. The
numbers were recorded with a woman’s voice
and presented using a personal computer
(APTIVA 2134 J3X, IBM, Tokyo, Japan).
Procedure. In the practice session, subjects
learned the throwing task without the simultaneous secondary task. In the performance
session, subjects performed the throwing task
as well as the secondary task. After the ready
signal, the five digits were presented. The start
signal was activated during the presentation
of digits, so that the subjects had to begin the
throwing task as the digits were being presented. The start signal was activated in an
interval between the digit presentation, so that
the subjects were not prevented from hearing
the digit by the audible beep of the start signal.
Results
Performance scores. Table 1 shows mean
performance scores. A one-way analysis of
variance (ANOVA) with repeated measures,
conducted on the AEs and VEs separately,
revealed a significant main effect of the session
in the AE, F(2, 20) = 29.84, p , .01, and in the
VE, F(2, 20) = 16.23, p , .01. A post-hoc
analysis showed that both the AEs and the VEs
were reduced significantly in the post-practice
© Japanese Psychological Association 2000.
T. Higuchi
172
Table 1. Mean (SD) absolute errors (AEs) and
variable errors (VEs) on the performance scores
in Experiment 1
Session
Error
Pre-practice
Post-practice
Dual task
AE
VE
25.5 (5.06)
12.1 (1.31)
12.0 (2.85)
7.1 (1.70)
17.6 (4.42)
10.4 (2.80)
session and increased significantly in the dualtask session.
Variability of joint coordination. Figure 2A
shows the mean within-subject variability, which
was represented by the standard deviation
of cross-correlations for angular displacement.
A two-way repeated measures ANOVA (3 coordinations × 3 sessions) revealed neither a main
effect of session nor an interaction between
coordination and sessions, F(2, 20) = .24, ns and
F(4, 40) = 1.42, ns, respectively.
Figure 2B shows the variability of crosscorrelations for angular velocity. An ANOVA
revealed that there was a marginally significant
interaction, F(4, 40) = 2.39, p , .07. Post-hoc
analysis revealed that the standard deviation
in the post-practice session was increased for
the shoulder-elbow coordination, and decreased
Discussion
The purpose of Experiment 1 was to examine
the effect of resource shortage induced by the
secondary task on the kinematic variability.
It was assumed that if the variability was
determined by the degree of automaticity, the
kinematic measures would not vary in the dualtask situation. The results revealed that the
kinematic variability was not affected by
the simultaneous secondary task, in spite of the
performance decrement. Therefore the kinematic variability can be regarded as an index
of automaticity.
0.35
(A)
0.3
0.3
0.25
0.25
Variability
Variability
0.35
for the shoulder-wrist. However, these values
did not significantly change in the dual-task
session.
Variability of release point. Variability of
the release point, represented by the standard
deviation, was calculated for horizontal and
vertical positions separately. Mean variability
scores in the pre-, post- and dual-task sessions
were 4.92, 3.77 and 3.45 cm for the horizontal
position, 5.27, 5.12 and 4.52 cm for the vertical
position, respectively. A one-way ANOVA with
repeated measures was conducted for each
position separately and showed no significant
effects, F(2, 20) = 1.53, ns, F(2, 20) = .90, ns,
respectively.
0.2
0.15
Shoulder-elbow
Shoulder-wrist
Elbow-wrist
0.2
0.15
0.1
0.1
0.05
0.05
0
0
Prepractice
Postpractice
Session
Figure 2.
(B)
Dual
task
Prepractice
Postpractice
Dual
task
Session
Mean within-subject variability of cross-correlations for angular displacement (A) and angular
velocity (B) in Experiment 1.
© Japanese Psychological Association 2000.
Disruption of kinematic coordination in throwing under stress
However, it must be noted that kinematic
variability did not reduce significantly after
the 150 throws, regardless of the performance
improvement. The outcome did not conform to
the expectation that the subject would stabilize
the movement to restrict degrees of freedom
(Vereijken et al., 1992). Therefore it can
be said that the kinematic variability did
not necessarily correlate with performance
variability.
Experiment 2
The purpose of Experiment 2 was to examine
the effect of stress on the two variability
measures, which were regarded as indices of
automaticity from the findings in Experiment 1.
If stress impairs automaticity, the degree of
freedom of movement, which was constrained
through practice, will be freed because of
deautomatization. As a result, consistent movement will be broken and the inter-trial variability of joint coordination and release point
will increase.
Method
Subjects. Eleven subjects with high traitanxiety scores on a Japanese version (Shimizu
& Imae, 1981) of the STAI (Spielberger,
Gorsch, & Lushene, 1970) were selected, in
order to see performance impairment clearly
(e.g., Calvo & Alamo, 1987; Terelak, 1990).
The 11 male volunteers (aged 18–23 years),
whose mean STAI trait score was 43.6 (SD 4.8),
were all new to the experimental task.
Procedure. In the performance session, the
subjects performed a throwing task under
evaluative stress. Before the performance
session, the subjects were instructed that this
experiment was one of the most important
parts of the project, which was taken seriously
by many professors. The importance of accomplishing two particular goals in the next block
was stressed: to improve their scores from
previous blocks, and to be sure to throw the
ball within the outer perimeter of the circular
target in every trial (the radius of the outer
circle was 28 cm).
173
Table 2. Mean (SD) absolute errors (AEs) and
variable errors (VEs) on the performance scores in
Experiment 2
Session
Error
Pre-practice
Post-practice
Dual task
AE
VE
24.5 (6.46)
12.4 (3.41)
15.0 (6.17)
8.0 (2.16)
18.1 (5.56)
9.3 (2.59)
Results
Performance scores. Table 2 summarizes
performance in the throwing task. A one-way
ANOVA with repeated measures was conducted on the AEs and the VEs separately, and
revealed a significant main effect of session on
both the AE and the VE, F(1, 10) = 22.80,
p , .01, F(1, 10) = 14.84, p , .01, respectively.
Post-hoc analysis showed that the AE was
reduced significantly in the post-practice session and was increased significantly in the
stress session. The VE was reduced in the postpractice session but did not change significantly
in the stress session.
Variability of joint coordination. Figure 3A
shows the mean within-subject variability of
the cross-correlations for angular displacement.
A two-way ANOVA with repeated measures
revealed that there was a marginal main effect
of session, F(2, 20) = 2.81, p , .10. Post-hoc
analysis found a significant tendency for an increase in the stress session (p , .05). Figure 3B
illustrates the mean within-subject variability
of the cross-correlation for angular velocity. A
main effect of session, F(2, 20) = 3.76, p , .05,
was significant. There was a significant decrease
in the post-practice session and a significant
increase in the stress session.
Variability of release point. Mean variability
scores in the pre-practice, post-practice, and
stress sessions were 4.26, 3.60 and 2.51 cm for
the horizontal position, 5.40, 4.71 and 3.82 cm
for the vertical position, respectively. An
ANOVA with repeated measures showed that
a main effect of session was significant in the
horizontal position, F(2, 20) = 5.25, p , .05.
The variability score in the stress session was
lower than that in the pre- and post-practice
session.
© Japanese Psychological Association 2000.
T. Higuchi
174
(A)
0.35
0.3
0.3
0.25
0.25
Variability
Variability
0.35
0.2
0.15
Shoulder-elbow
Shoulder-wrist
Elbow-wrist
0.2
0.15
0.1
0.1
0.05
0.05
0
0
Prepractice
Postpractice
Stress
Session
Figure 3.
(B)
Prepractice
Postpractice
Stress
Session
Mean within-subject variability of cross-correlations for angular displacement (A) and angular
velocity (B) in Experiment 2.
Discussion
The purpose of Experiment 2 was to examine the
effect of stress on the variabilities of the two
kinematic measures in throwing, namely the
joint coordination in the arm and the hand
position at the point of releasing the ball. These
variabilities were regarded as indices of the
automaticity from the findings in Experiment 1,
in which the variabilities did not change in spite
of the performance decrement caused by the
resource shortage for motor control.
The conscious-control theory and the
resource-shortage theory predict different effects
of stress on these variabilities. The former theory
predicts a harmful effect because it proposes
that stress leads to deautomatization and thus
interferes in learned stability of the movement.
In contrast, the latter theory predicts no harmful effects because even if stress reduces the
resources available for motor control, the kinematic variabilities do not change in the case of
resource shortage.
The result of variability in joint coordination
supports the conscious-control hypothesis.
Kinematic variability, which was represented
by the standard deviation of cross-correlations,
was significantly increased in terms of angular
velocity and was marginally increased in terms
of angular displacement.
© Japanese Psychological Association 2000.
However, the result of variability in the release point was not in line with the predictions
of either theory. The variability in the horizontal position decreased significantly in the
stress session, despite a decline in throwing
performance. This result is somewhat surprising, because in many studies the consistent
release position has been highly correlated
with skilled throwing (e.g., Hore et al., 1994,
1995; Hore, Watts, & Tweed, 1996; McDonald
et al., 1989).
Did the subjects consistently reproduce only
the release point, or the whole hand trajectory?
Figure 4 shows a comparison of the trajectories
of four subjects in the post-practice and the
stress session. It seems that not all of the
hand positions throughout the arm swing had
become stable by the stress session. To confirm
this visual inspection statistically, the variability
of hand position at the takeback was further
analyzed as a representation of the trajectories.
Mean variability scores in the post-practice and
stress sessions were 3.34 and 2.83 cm for the
horizontal position, and 1.58 and 1.37 cm for
the vertical position, respectively. A one-way
ANOVA with repeated measures showed no
difference between the sessions. This suggests
that not all of the hand positions throughout
the swing of the throw were stabilized under
Disruption of kinematic coordination in throwing under stress
175
(A) Post-practice session
TA
MO
TY
SS
start
forward
swing
end of
takeback
Vertical
(B) Stress session
Horizontal
Figure 4.
Trajectories of the hand LED on four subjects (TA, MO, TY, and SS) in the post-practice session
(A) and the stress session (B).
stress. One would expect the subjects to conform to the conscious-control mode especially
in reproducing consistent release.
General discussion
Past studies that support the conscious-control
theory have a problem in that the results can
also be explained by the resource-shortage
theory. However, in this study it is hard to
justify the results from the viewpoint of the
resource-shortage theory. In Experiment 1 the
variability of kinematic measures did not
change even when the resources available for
motor control were reduced.
The conscious-control theory offers a more
plausible explanation of the results, although it
does not explain them entirely. According to
this theory, the desire to perform well causes a
subject to use conscious control because it
can increase accuracy (see Willingham, 1998).
In Experiment 2, the subjects were instructed
to throw as accurately as possible in the stress
session. To accomplish the goal, one might expect the subjects to attempt to reproduce their
movement by conscious control. This tendency
was reflected in the consistency of the release
point. However, the accomplishment of accurate throws (invariant position of ball release)
by conscious execution disrupted the invariance
in joint coordination, and this may explain the
subjects’ poor performance.
If these interpretations are true, the results
also suggest that the conscious-control theory
needs revision. In Experiment 2, the hand
position at ball release was initially inconsistent, but became stable through practice.
The theory predicts the hand position should
become variable again under stress, because
the movement regresses to that in the early
stages of learning. However, in the stress
session hand position became more stable,
© Japanese Psychological Association 2000.
T. Higuchi
176
although throwing performance was impaired.
Therefore the change from automatic to
conscious control does not mean regression to
the initial stages of learning. Considering that
consistent release is usually critical for throwing performance, the change to conscious
control reflects adherence to a control strategy
that the performers think is critical for better
performance.
Although the results support the consciouscontrol theory, it must be noted that conscious
control itself does not have a detrimental effect
on motor performance. Some earlier findings
have suggested the usefulness of the conscious
strategy on motor control or learning. For example, augmented feedback about movement
kinematics is reported to have improved skill
learning (e.g., Schmidt & Young, 1991; Todorov,
Shadmehr, & Bizzi, 1997). Dadkhah (1998)
showed that increasing the body consciousness
of disabled sportsmen helped them to attain
better body balance. Notably, according to
Bäckman and Molander (1991), the adoption of
a conscious-control strategy did not necessarily
impair the performance of highly skilled players.
These findings imply that whether conscious
control disrupts performance under stress or
not depends on the interaction between the
demand of the skill (e.g., speed, timing) and the
degree of skill (e.g., expert or novice).
Conclusion
The present study tested the conscious-control
theory, by examining the effect of stress on
automaticity of motor control. In addition to
a worsening of performance, the consistency
of joint coordination was disrupted, while the
release point was fixed. The results support the
conscious-control theory, although the results
concerning the release point call for a revision
of the theory. One possibility is that the effort
to throw accurately caused the subjects to
control the release point consciously, because
they thought that the release point was the
most important factor influencing the accuracy
of ball direction. Conversely, though, the use of
conscious control disrupted the more dynamic
joint coordination. Therefore the variability
© Japanese Psychological Association 2000.
of joint coordination increased, resulting in a
decrement in performance.
References
Bäckman, L., & Molander, B. (1991). Cognitive
processes among skilled miniature golf players:
Effects of instructions on motor performance,
concentration time, and perceived difficulty.
Scandinavian Journal of Psychology, 32, 344–351.
Baumeister, R. F. (1984). Choking under pressure:
Self-consciousness and paradoxical effects of
incentives on skillful performance. Journal of
Personality and Social Psychology, 46, 610–620.
Calvo, M. G., & Alamo, L. (1987). Test anxiety and
motor performance: The role of muscular and
attentional demands. International Journal of
Psychology, 22, 165–178.
Dadkhah, A. (1998). The effect of dohsa-hou on body
consciousness in disabled sportsmen. Japanese
Psychological Research, 40, 134–143.
Darke, S. (1988). Effects of anxiety on inferential
reasoning task performance. Journal of Personality and Social Psychology, 55, 499–505.
Deikman, A. J. (1969). Deautomatization and the
mystic experience. In C. T. Tart (Ed.), Altered
states of consciousness (pp. 23–43). New York:
Wiley.
Easterbrook, J. A. (1959). The effect of emotion on
cue utilization and the organization of behavior.
Psychological Review, 66, 183–201.
Eysenck, M. W. (1979). Anxiety, learning and
memory: A reconceptualization. Journal of
Research in Personality, 13, 363–385.
Eysenck, M. W. (1982). Attention and arousal. New
York: Springer-Verlag.
Hardy, L., Mullen, R., & Jones, G. (1996). Knowledge
and conscious control of motor actions under
stress. British Journal of Psychology, 87, 621–636.
Hinrichs, R. N. (1982). Upper extremity function in
running. Unpublished doctoral dissertation.
Pennsylvania State University.
Hore, J., Watts, S., Martin, J., & Miller, B. (1995).
Timing of finger opening and ball release in fast
and accurate overarm throws. Experimental
Brain Research, 103, 277–286.
Hore, J., Watts, S., & Tweed, D. (1994). Arm position
constraints when throwing in three dimensions.
Journal of Neurophysiology, 72, 1171–1180.
Hore, J., Watts, S., & Tweed, D. (1996). Errors in the
control of joint rotations associated with inaccuracies in overarm throws. Journal of Neurophysiology, 75, 1013–1025.
Humphreys, M. S., & Revelle, W. (1984). Personality,
motivation and performance: A theory of the
Disruption of kinematic coordination in throwing under stress
relationship between individual differences and
information processing. Psychological Review,
91, 153–184.
Jones, G. (1995). More than just a game: Research
developments and issues in competitive anxiety
in sport. British Journal of Psychology, 86,
449–478.
Lee, T. D., & Swinnen, S. P. (1993). Three legacies of
Bryan and Harper: Automaticity, variability and
change in skilled performance. In J. L. Starkes &
F. Allard (Eds.), Cognitive issues in motor expertise
(pp. 295–315). Amsterdam: North-Holland.
Leon, M. R. (1989). Anxiety and the inclusiveness of
information processing. Journal of Research in
Personality, 23, 85–98.
Logan, G. D. (1985). Skill and automaticity: Relation,
implications, and future directions. Canadian
Journal of Psychology, 39, 367–386.
McDonald, P. V., van Emmerik, R. E. A., & Newell,
K. M. (1989). The effects of practice on limb
kinematics in a throwing task. Journal of Motor
Behavior, 21, 245–264.
MacLeod, C., & Mathews, A. (1988). Anxiety and
the allocation of attention to threat. Quarterly
Journal of Experimental Psychology, 40A,
653–670.
Masters, R. S. W. (1992). Knowledge, knerves and
know-how: The role of explicit and implicit
knowledge in the breakdown of a complex motor
skill under pressure. British Journal of Psychology,
83, 343–358.
Neiss, R. (1988). Reconceptualizing arousal: Psychological states in motor performance. Psychological Bulletin, 103, 345–366.
Newell, K. M., & McDonald, P. V. (1994). Learning
to coordinate redundant biomechanical degrees
of freedom. In S. P. Swinnen, J. Massion,
H. Heuer, & P. Casaer (Eds.), Interlimb coordination: Neural, dynamical, and cognitive constraints
(pp. 515–536). London: Academic Press.
Platz, T., Denzler, P., Kaden, B., & Mauritz, K.-H.
(1994). Motor learning after recovery from
hemiparesis. Neuropsychologia, 32, 1209–1223.
Rapee, R. M. (1993). The utilization of working
memory by worry. Behavior Research Therapy,
31, 617–620.
177
Schmidt, R. A. (1988). Motor control and learning:
A behavioral emphasis (2nd ed.). Champaign,
IL: Human Kinematics.
Schmidt, R. A., & Young, D. E. (1991). Methodology for motor learning: A paradigm for
kinematic feedback. Journal of Motor Behavior,
23, 13–24.
Shimizu, H., & Imae, K. (1981). Development of
the Japanese edition of the Spielberger State–
Trait Anxiety Inventory (STAI) for student use.
Japanese Journal of Educational Psychology, 29,
348–353. (In Japanese.)
Singer, R. N., Lidor, R., & Cauraugh, J. H. (1993).
To be aware or not aware? What to think about
while learning and performing a motor skill.
Sport Psychologist, 7, 19–30.
Sorg, B. A., & Whitney, P. (1992). The effect of trait
anxiety and situational stress on working memory
capacity. Journal of Research in Personality, 26,
235–241.
Spielberger, C. D., Gorsch, R. L., & Lushene, R. E.
(1970). Manual for the State-Trait Anxiety
Inventory. Palo Alto, CA: Consulting Psychologists Press.
Terelak, J. (1990). Individual differences in anxiety
level and psychomotor performance. Personality
and Individual Differences, 11, 771–775.
Todorov, E., Shadmehr, R., & Bizzi, E. (1997).
Augmented feedback presented in a virtual
environment accelerates learning of a difficult
motor task. Journal of Motor Behavior, 29,
147–158.
van Rossum, J. H. A., & Bootsma, R. J. (1989).
The underarm throw for accuracy in children.
Journal of Sport Science, 7, 101–112.
Vereijken, B., van Emmerik, R. E. A., Whiting, H. T.
A., & Newell, K. M. (1992). Free(z)ing degrees
of freedom in skill acquisition. Journal of Motor
Behavior, 24, 133–142.
Willingham, D. B. (1998). A neuropsychological
theory of motor skill learning. Psychological
Review, 105, 558–584.
Wine, J. (1971). Test anxiety and direction of
attention. Psychological Bulletin, 76, 92–104.
(Received Feb. 12, 1999; accepted Jan. 22, 2000)
© Japanese Psychological Association 2000.