Nowadays, science and technology development has propelled all researchers
develop worldwide variety field which among them is in field of sports. In the
field of sports, all researchers have made numerous studies about performance
and development of athlete at every sort of game with used biomechanics method
which it to increase sports development quality for every country. The most
widely studied soccer kick is the instep kick (Lees and
Nolan, 1998; Nunome et al., 2006; Apriantono
et al., 2006). An understanding of the biomechanics of kicking can
assist the coaching process. Coaching experience, combined with knowledge of
a mechanical model of the desired performance, is regarded as necessary for
a coach to correct performance (Elliott, 2001; Lees,
Instep kicking has been studied from the youngest age groups to seasoned professionals
(Asami and Nolte, 1983; Luhtanen,
1988). The instep kick generally uses the laces of the shoe to strike the
ball. A key factor in the success of any kick in soccer is the placement of
the supporting foot (the non-kicking foot plant) If the support foot is improperly
positioned relative to the ball, the resultant kick will likely be errant. When
kicking with the right foot, the approach should be from behind and to the left
of the ball; the approach is made from behind and to the right of the ball when
kicking with the left foot.
Success of an instep soccer kick depends on various factors including the distance
of the kick from the goal, the type of kick used, the air resistance and the
technique of the main kick which is best described using biomechanical analysis.
Previous reviews have examined biomechanics of soccer movements in-detail (Lees,
1996; Lees and Nolan, 1998). The basic (two-dimensional)
kinematics of the lower limb segments during instep soccer kicks have been previously
reviewed (Lees, 1996; Lees and Nolan,
1998). These include examination of angular position-time and angular velocity
curves during the kick as well as the linear kinematics of the joints involved.
The higher the speed of the foot before impact, the shorter the foot-ball contact
and the highest the ball speed. For this reason, the ball-to-foot speed ratio
has been considered as an index of a successful kick (Asami
and Nolte, 1983; Kellis et al., 2004; Lees
and Nolan, 1998; Nunome et al., 2006; Plagenhoef,
1971). For instep kicks, ball-to-foot speed ratios reported in the literature
range from 1.06 to 1.65 (Asami and Nolte, 1983; Isokawa
and Lees, 1988; Kellis et al., 2004; Kellis
et al., 2006; Nunome et al., 2006)
depending on the foot area used to examine foot speed.
A soccer kick may be performed either from a stationary position or at a certain
distance from the ball. The approach consists of several steps and can be performed
at an angle relative to the ball. The length, speed and angle of approach are
the most important aspects of this preparatory movement which has a significant
effect on soccer kick success (Isokawa and Lees, 1988;
Kellis et al., 2004). Kicking from an angled
approach up to 45° may increase ball speed, although this increase may not
be statistically significant (Isokawa and Lees, 1988).
Kick in habit its used when player taking free kick, penalty kick and also shooting.
So in this analysis, movement of kicking through impact phase in ball when player
making kick will be study. Apart from that, injury in fetlock often happened
excess loading result given when kick carried out. Effect which found of this
problem cause failed player giving performance and good game and often make
mistakes when play.
Further, kicking with running approach demonstrates higher ball speed values
compared with static approach kicks. To our knowledge, the difference between
one-step and multi-step approach on ball speed values is not clear. However,
practice shows that soccer players prefer a multi-step approach, most often
2 or 3 steps prior to the main kicking action. Ball speed values during the
maximum instep kick range from 18 to 35 msec-1 depending on various
factors, such as skill level, age, approach angle and limb dominance. Accurate
kicks are generally slower than powerful kicks. The full instep kick has been
biomechanically studied in detail defining its typical components including
the foot/ball contact phase. Successful kicks need to be fast and accurate,
especially when kicking on goal. The distance, velocity and angle imposed kicking
are the important parameters involving the kicking activities where it can contribute
high impact to effectiveness of kicking (Kellis et al.,
2004). Therefore, this study will focus more on the biomechanics analysis
towards the soccer players besides to identifying to their kicking action and
technique using the instep kicking. Among the different instep kicking techniques
the full instep kick is the fastest, followed by the inner and outer instep
kicks (Neilson and Jones, 2005). In this research, the
quantitative biomechanics analysis was introduced. The study was executed by
quantitative measurement as well as quantitative biomechanics analysis. On the
other hand, if the aspect is assessed by observation and survey, the results
of the analysis are known as qualitative biomechanical analysis (Luhtanen,
MATERIALS AND METHODS
Subject selection: Most important thing is subject has to be in good health during experiment because the kick that will be done is from self force. The subject was selected from professional soccer player with average heights of Asian. Height, weight, age and body size of the subject was considered as data for analysis Observation started when subject stops kicking the ball where posture of the leg from waist to knee and then to ankle was observed.
Study setup: The study was conducted on July 2008 at the field of National Sports Institute (ISN). One subject has been chosen to do this study. The deflection tape was attached on the lower limb of the subject part that is on the waist, knee and also ankle. The subject movement will be recorded via video recording by video camera that will focus in section lower limb of the subject. Data recording were done with video/picture using two Sony video camera that located at the side and the front view of the subject when making the kicking. This camera can analyse as fast as 0.02 sec frame-1. Preparation for data recording is on Fig. 1. Figure 1 show the study setup for subject making an instep kicking. Two camera will be using for this study that have been place at the front and side view. The camera will focus on the lower limb of the subject when the subject making a kicking to get a better visualized.
Figure 2 presents the methodology process for this study.
It started with selection of the subject. The subject must be in good condition
and release from any injury.
The observation will started when the subject making a kicking and it be focused
on the lower limb. From that, the data of this study will be analyse about the
motion, ball distance, maximum force and multiple linear. Lastly, the force
equation will be identify.
Data analysis: In this study, the subject doing instep kick with one
step, two step and three step run with two times trial. The subject making instep
kicking by using the right leg. Instep kicking activities were recorded by high
speed camera video and later the image will be edited through still images according
to the frame of every 0.02 per sec-1. Instep kicking were analysed
by using the Silicon Pro Coach software (Morrison, 1997).
From this analysis, the velocity, acceleration, distance and kicking angle was
identified as significant or not significant to the force model. The statistical
analysis was conducted by using Minitab software (Farber,
RESULTS AND DISCUSSION
Motion analysis: Figure 3 presents the edited images
from front view according to frame and Fig. 4 presents the
edited images from side view according to frame.
||Front view kicking pictures according to frame
||Side view kicking pictures according to frame
Kicking in each frame will be analyzed according to angle, acceleration, kicking
velocity and frame distance at ankle.
Figure 5 shows the angle where the subject started making
kick and the angle when kicking in ball is carried out. The reading angle also
gained by using reading at every frame. This angle was measured from hip point,
knee point and ankle point of the kicking leg. The length, speed and angle of
approach are the most important aspects of this preparatory movement which has
a significant effect on soccer kick success (Isokawa and
Lees, 1988; Kellis et al., 2004).
Figure 6 shows, the subject which uses right leg started making a kicking. The analysis which made are when subject doing a two step run which it will be analyzed by using software Silicon Pro Coach. In this figure, it shows the velocity relationship fight every time frame adopted and also the distance when making kicking.
Figure 7 shows the maximum velocity produced in frame 4, which before the foot impact and hit into the ball. The speed at the ankle when frame 4 is 8.20 m sec-1.
Figure 8 shows the beginning impact in ankle and ball part which the velocity in ankle will decline consequence of the impact which occurred. Velocity at the moment is 7.67 m sec-1 which velocity value lesser as much as 0.53 m sec-1. After the impact happened, the velocity will decreased until subject finish doing kicking. Kicking distance will be measured after kick carried out and drop ball falling on field surface will be recorded his distance.
Figure 9 shows the resultant angle when ankle and ball touching
(foot and ball impact happened). This angle is analyzed from waist, knee and
ankle part which angle resultant is 141°. From this study, it show that
the highest force produced in frame 4, where it occur when the ankle touch with
ball. Here, the force considered is at ankle part because that part more hit
the ball when making kick compared to knee part and waist.
||The angle of subject making kicking
||Graf velocity against time
||Graf velocity fight maximum time achieved
The results of this study indicate that the angle of kicking is 39°. Good
kicking angle has been stated previously in earlier research the angular kick
is 45°. The foot velocity reduction before the foot touching the ball would
give the high impact to the force inflicted by foot on ball. Anderson
and Sidaway (1994) analysed the co-ordination of the low instep kick using
timing variables and angle plots.
||Graf velocity against time at frame 5
||The angle of right leg subject
||Ball distance kicked for all run type
In this analysis, it found time and distance is course of doing dependent
Table 1 presents the ball distance kicked achieved from the
subject in two trials. It shows that the three steps run have a better distance
then other type run when making kicking. So, making kicking with a lot of run
can give a better distance. Further, kicking with running approach demonstrates
higher ball speed values compared with static approach kicks (Opavsky,
Table 2 shows the maximum velocity resultant is in three
step run of the left leg subject namely the maximum velocity resultant was 11.71
||The maximum velocity for all run type
||The maximum force resultant for each run type
For the right leg subject the maximum velocity resultant is 8.20 m sec-1.
The foot velocity before ball kicked is directly proportional with force imposed
In this analysis, the force resultant of lower limb can be analyse through Minitab and Silicon Coach Pro software. With run expansion, the force resultant before ball kicked will be increase. From Table 3, it show that the highest average force of right leg produced in force model analysis which using the three step run. In three step run, the highest average force produce is 5879.60 N and the highest average velocity is 8.2 m sec-1.
Multiple linear modelling:
From the multiple linear regression for all variables it recorded that R2
= 1.000 and the output R2 x 100% = 100% where R2 is the
coefficient of determination. This can be interpreted as indicating that the
model containing distance, acceleration and angle for approximately 100% of
the observed variability in force. The model equation that been used is:
Figure 10 show the multiple linear graf for all variable
in three step run. The Minitab output show that the least square point estimates
of the model parameter are:
where, β1 is velocity, β2 is acceleration and
β3 is distance. The multi linear model equation for three step
This study also show the multi linear model equation for all type run using
first step, second step and three step run:
||The multiple modeling for all variable in three step run
where, y is level of ability, x1 is velocity, x2 is acceleration
and also x3 is distance.
This study has shown that the highest average forces produced in force model analysis which using three step run. The highest average force of instep kicking is 5879.60 N, the highest average velocity is 8.2 m sec-1 with distance kick as much as 47.85 m and the multi linear model equation is í = - 18.1+711x1+0.146 x2+396x3. It also show that the instep kicking using a lot of step run will give the highest average force, average velocity and distance. This study was done to obtain the equation that relates with the variables and to get the force model equation when kicking have been made. It is hoped that this study would be beneficial to the Malaysian soccer to get the better techniques in kicking and avoid from injury.
This study was financially supported by Ministry of Higher Education of Malaysia under Sport Research Grant with a close collaboration by National Sports Institute of Malaysia (06-01-02-SF0543).