S.Ü. Müh.-Mim. Fak. Derg., c.23, s.

3, 2008
J. Fac.Eng.Arch. Selcuk Univ., v.23, n.3, 2008

KINEMATIC ANALYSIS OF PENALTY KICK IN SOCCER

Ayhan GOKTEPE, 2Hakan KARABORK, 3Emre AK, 3Seref CICEK, 3Feza KORKUSUZ
1

1Selcuk University, Technical Science College, Konya

2Selcuk University, Faculty of Engineering and Architecture, Department of Geodesy and

Photogrammetry, Konya
3Middle East Technical University, Faculty of Education, Department of Physical Education and Sport,

Ankara

ABSTRACT: Kinematics of the instep penalty kick to four different targets (50cm2) placed at the
upper left (UL), lower left (LL), upper right (UR), and lower right (LR) corners in the goal. Five
colligate male soccer players were examined for their knee flexion and ankle extension strategies. The
swing, ball contact and follow through phases were analyzed by using a dual camera and Pictran
software system. Results revealed that participants had significantly higher ankle extension while
hitting the target at the UR (m=77.6 deg, sd=10.5) and LR (m=84.4 degree, sd=10.1) corners. In
conclusion players presented similar knee flexion but not ankle extension kinematic strategies at the
contact and follow through phases of the instep penalty kick to different corners in the goal.

Keywords: Digital photogrammetry, kinematics, motion analysis, penalty kick.

Futbolda Penalt At n Kinematik Analizi

ÖZET: Futbolda penalt at , kalenin sa üst, sa alt, sol üst ve sol alt kö lerine 50 cm
büyüklü ünde bir hedef konularak gerçekle tirilmi tir. 5 adet sporcunun topa vuru s ras nda diz ve
ayak bile inde olu an aç lar kinematik olarak incelenmi tir. Haretketin ba lang ç an ndan itibaren
topa vuru an na kadar olan görüntüleri çift kamera ile çekilmi tir. Çekilen görüntüler Pictran
fotogrametri yaz ile de erlendirilmi tir. De erlendirme sonucunda topa vuru esnas nda dizde
olu an aç lar, ayak bile inde olu an aç lara gore istatiksel olarak daha anlaml bulunmu tur.

Anahtar Kelimeler: Digital fotogrametri, hareket analizi, kinematik, penalt at .

INTRODUCTION professional players focused on the variables

that predict the success of the instep kick. Elite
Biomechanics and movement analysis in compared to young players developed a
soccer can be defined as the characteristics of a relatively constant mechanical strategy for the
skill quantitatively. Quantifying the movement instep kick (Ben-Sira, 1980; Gainor et al., 1978;
of certain task like of the penalty kick can be Hay, 1996; Tsaousidis and Zatsiorsky, 1996).
used to improve the performance of that skill From the mechanical point of view, the instep
(Bases 2008). kick is a multiplanar movement and the motion
The free kick in soccer including the of a single segment within a linked system is
penalty kick is the full-tension and almost nonlinear and cannot be solely attributed to
always deterministic momnet of a game. muscle forces and moments acting on the lower
Although each player develops individual extremity (Barfield, Kirkendall, Yu, 2002).
skills and strategies, the most frequently used Biomechanical analysis of a well executed
technique is the instep kick. Previous studies instep kick requires the assessment of the
(Asami and Nolte, 1983; Bloomfield et al., 1994; whole lower extremity kinetic chain.
Barfield, 1997) in young and seasonal
46 A. GOKTEPE, H. KARABORK, E. AK, S. CICEK, F. KORKUSUZ

Previous studies focused on the ball (Dragonfly Express, Point Grey Research, 2006)
velocity as an indication of success in instep at a frame rate of 60 frames/second. The
kick. However, a well documented kinematic cameras were placed at approximately 90
analysis of this movement in relation with degree angle to each other. A cage that covered
success was not documented in some detail. the volume of 1.0 m x 1.0 m x 2.0 m at 12 control
The instep kick can be divided into 3 phases. points was used to calibrate the space in which
These are swing, ball contact and follow- the instep penalty kicks were performed
through. Each phase should be executed (Figure 1). Photogrammetric restitutions were
successful enough to kick the ball to the conducted using the Pictran Software (Technet
desired location. Therefore, the aim of this GmbH, Germany). Adjustment process was
study was to investigate the ankle extension provided in bundles of 6-8 control points.
and the knee flexion differences of instep kick Three dimensional coordinates of the marked
during penalty where the success was indicated points were defined after the adjustment
4 different locations, the upper left (UL), the process was completed. Ankle extension and
lower left (LL), the upper right (UR), and the knee flexion were determined from the images.
lower right (LR) inner corners of the goal. The swing, ball contact and follow through
phases were assessed according to Barfield et al
METHODS (1998).

Five collegiate male soccer players (age= RESULT

21.5±2.2 years; body weight= 68.4±4.6 kg; body
height= 1.74±5.6 m; soccer experience= 10.4±5.0 Analysis of variance results revealed that
years) volunteered for the study. Each player there was no significant knee flexion
executed 5 successful instep penalty kicks to difference when the instep kick was used to hit
the targets (50 cm2) placed at the 4 (UL, LL, UR, the UL, LL, UR and LR targets at the swing,
and LR) inner corners of the goal. Five contact and follow through phases (Figure 2).
reflective markers were used to define the Players tend to use the similar knee flexion
thigh, the shank and the foot. Markers were strategy for all targets.
placed on the a) right anterior superior iliac Results revealed that there was no
spine, b) lateral condyle of the right knee, c) significant ankle extension difference at the
lateral malleolus, d) posterior of the calcaneus swing phase. However, ankle extension
and e) distal metatarsal head of the fifth differed significantly at ball contact
phalanx. (F(3,16)=11.61, p=.00) and follow through
(F(3,16)=3107, p=.05) phases.
Pair-wise comparison of the contact phase
revealed that players had significantly higher
ankle extension when shooting the ball to the
UR corner (m =77.6 degree, sd=10.5) and LR
corner (m=84.4 degree, sd =10.1) when compared
to the LL corner (m =56.2 degree, sd =9.6) and
UL corner (m=59.6 degree, sd =4.2).
Results for the follow through phase
revealed that players presented significantly
higher ankle extension when shooting the ball
to the LR corner (m =66.8 degree, sd =7.05) when
compared to the LL corner (m =56.2 degree, sd
Figure 1. Penalty kick. =5.97) (Figure 3).
ekil 1. Penalt at .
DISCUSSION & CONCLUSION
The instep penalty kicks were recorded at a
stereoscopic view with two digital cameras
 Kinematic Analysis of Penalty Kick In Soccer 47

Players presented a similar knee flexion our knowledge, this perhaps is the first study
strategy while shooting the ball to different comparing lower extremity joint kinematics at
locations in the goal in each phase of the instep instep penalty kick to different locations in the
kick. However, ankle extension at ball contact goal.
and follow through phases were different
when the LR and LL corners were targeted. To

Figure 2. Knee flexion strategy of players.

ekil 2. Diz fleksiyon aç .
48 A. GOKTEPE, H. KARABORK, E. AK, S. CICEK, F. KORKUSUZ

Figure 3. Ankle extension strategy of players.

ekil 3. Ayak bilek aç .

The study was limited to collegiate male negatively affected and the probability of
soccer players. The advantage of the study was missing the penalty is increasing. Nunome,
field measurements. Shinkai et al. (2007) (2006), found that highly skilled soccer players
focused on the motion of the foot at the contact have better inter-segmental motion for both the
phase of the kicking movement. They found preferred and non-preferred leg.
that the foot was plantarflexed, abducted and In conclusion, our results presented that
everted during the contact with the ball. They players had similar knee flexion but not ankle
also suggested that after the foot contact with extension kinematic strategies at the contact
the ball it does not have any effect on the and follow through phases of the instep
velocity of the ball (Shinkai, 2007). penalty kick to different corners in the goal.
Apriantono et al. (2006), investigated the
effect of muscle fatigue on the kinematics of ACKNOWLEDGEMENTS
instep kicking and found that fatigue does
have a negative effect on the kinematics of the This study is funded with a grant
movement. (Apriantono, 2006). As we think (106M124) from Technical and Scientific
about the penalty kick in an actual game, it can Research Council of Turkey (TUBITAK),
be said that as the player develops fatigue, the Turkey.
kinematics of his/her kicking action could be

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