Passing performance:
Actions that led to directing the ball to the recipient
(teammate) by a proper passing technique were labeled
good performance or successful passing against actions
that led to loss of the ball after sending it to a recipient
were labeled low performance or failed passing.
Successful passes were counted as rate index after
dividing by total passing counts throughout the minutes
of playing. They are simply presented as percentile
ranks rather than base rates.
The performance criteria have been acknowledged
by two sport scientists and two elite level soccer
coaches as sufficient trustworthy to support practice
with elite players. Performance data were collected
using match analysis procedures [24] for each
competitive league game over the three-match period
(270 min) for both groups; in baseline and post
intervention phase. All soccer matches before and after
intervention, were videotaped and performance
variable evaluated through a close-up video analysis by
a professional coaching board that consisted of four
certified coaches working in national football leagues.
Game analysis consisted of full and careful inspection
of videotaped real competitions by the coaches’ board
which resulted in a single record for every pass as
successful or failed. They were blind to players’
conditions at all. Good performance defined as if the
ball was sent to the recipient successfully during a
game; it is different from experimental passing tests
which the players are scored on a scheduled protocol
for short or long passes in a laboratory setting.
Furthermore, passing performance was considered to
have the same value in every soccer field zone.
Procedure:
A prospective interventional study was conducted in
order to test efficacy of an ecological imagery
intervention on soccer performance during league
competitions. Players in imagery group were invited to
participate in the course including both Cognitive
specific and cognitive general imagery training
interview to evaluate any history of mental imagery
training in the baseline. As mentioned above we have
repeated the interviews for imagery group on a weekly
basis. All players reported little previous training in
imagery for soccer passing. Meanwhile, interviews
revealed that players were able to produce appropriate
images related to skill performance and have followed
the training program guidelines during the intervention
phase. The course of imagery training spanned an 8-
week period during which participants were involved
in a weekly imagery session guided by the lead author.
Educational classes were conducted in their clubs in a
private room setting.
Imagery training program:
Imagery training program consisted of an introductory
session for defining and explanation of sport imagery
and its application in soccer. Players completed
exercises to first develop external and then internal
imagery, real time speeds of images and create images
applying all senses to experience a perfect skill
performance. They were recommended to practice
imagery with their eyes closed to start with; by
increasing in experience of imagery practice they could
continue with eyes either open or closed. We explained
and taught them mental imagery regarding how to 1-
Relax the mind and concentrate on here and this time
2- Imagine a scene of a soccer game as the field of
practice 3- Put themselves in the picture 4- Orient to
the environmental cues like the others’ positions and
movements and 5- Start the practice in the mind to do
the best of performance. Then we discussed
specifically about passing during a real soccer game.
We showed them some examples of perfect passing
skills by expert models through competitions, but did
not obligate them to only use these pictures; they were
also taught to memorize their best practice in passing
performance and then rehearse in their mind over and
over again. We were trying to provide a training
program according to the environmental basis of soccer
performance. Players were taught to orient to the
advance cues in images of real games including
opponents, teammates, sounds and voices and search
for the best candidate for passing (as components of
cognitive general imagery). They also practiced to do a
perfect passing technique; They remembered to focus
on foot movements, angles, velocity, point of the ball
stroke, kick force and finally following the ball toward
the recipient (as components of cognitive specific
imagery).
We have asked our soccer expert committee to
develop the imagery script. They provided researchers
with a passing performance scenario during a real
soccer game. From this, the researchers work the
imagery script. Imagery script included specific and
general cognitive elements of imagery functions
specific for soccer passing. Furthermore, to benefit the
learning and development of imagery skill, each player
was encouraged to recreate and develop a gamespecific
imagery script similar to the main template
provided by expert committee, including cognitive
aspects of passing imagery.
We kept the weekly training before daily soccer
practice sessions. When one works on mental skills, it
is important to keep the sessions short and interesting
for the soccer players. The imagery sessions conducted
in about 10-15 minutes in each session. Moreover,
participants were asked to practice and use the imagery
according to the script on a daily basis; before and after
training or competitions to find more about how to
perform better and better.
They were informed and randomly called back and
asked questions about the training course from
researchers every time of the study. We conducted the
feedback sessions at the end of each supervised
training session in order to help athletes update their
imagery skills. Furthermore, to provide a homogenous
training program, we focused on facilitating but not
debilitating aspects of imagery during training sessions
and through imagery scripts. We have followed the
players through feedback sessions and interviews to
conduct the imagery only for successful passing
throughout the program.
Analytic Approach:
Our measurements revealed that participants played
unequal times in either pre or post test occasions; as
their records showed various total passing counts per
game. Thus, the data can be assumed as
“Unbalanced”. Whereas ANOVA has some limitations
especially when you worked on unbalanced data,
generalized estimating equation (GEE) approaches
have several advantages, including the ability to handle
unbalanced data without some of the pathologies of
ANOVA methods. For the main analyses to estimate
the strength of the effectiveness of imagery
intervention on passing performance, we computed
odds ratio (OR) and 95% confidence intervals (CI) in
the total sample by Using GEE population-averaged
model. We then performed subgroup analysis on the
effects of imagery training on different age categories.
All statistical analysis was performed by the package
of Stata 9. The statistical significance level was set at
0.05.