Dynamics of the support leg in soccer instep kicking

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Dynamics of the support leg in soccer instep kicking a

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Koichiro Inoue , Hiroyuki Nunome , Thorsten Sterzing , Hironari Shinkai & Yasuo Ikegami a

Graduate School of Education and Human Development, Nagoya University, Nagoya, Japan

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Research Centre of Health, Physical Fitness and Sports, Nagoya University Nagoya, Japan

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Department of Human Locomotion, Chemnitz University of Technology, Chemnitz, Germany d

Faculty of Education, Art and Science, Yamagata University, Yamagata, Japan Published online: 28 Feb 2014.

To cite this article: Koichiro Inoue, Hiroyuki Nunome, Thorsten Sterzing, Hironari Shinkai & Yasuo Ikegami (2014) Dynamics of the support leg in soccer instep kicking, Journal of Sports Sciences, 32:11, 1023-1032, DOI: 10.1080/02640414.2014.886126 To link to this article: http://dx.doi.org/10.1080/02640414.2014.886126

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Journal of Sports Sciences, 2014 Vol. 32, No. 11, 1023–1032, http://dx.doi.org/10.1080/02640414.2014.886126

Dynamics of the support leg in soccer instep kicking

KOICHIRO INOUE1, HIROYUKI NUNOME2, THORSTEN STERZING3, HIRONARI SHINKAI4 & YASUO IKEGAMI2 1

Graduate School of Education and Human Development, Nagoya University, Nagoya, Japan, 2Research Centre of Health, Physical Fitness and Sports, Nagoya University Nagoya, Japan, 3Department of Human Locomotion, Chemnitz University of Technology, Chemnitz, Germany and 4Faculty of Education, Art and Science, Yamagata University, Yamagata, Japan

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(Accepted 18 January 2014)

Abstract We aimed to illustrate support leg dynamics during instep kicking to evaluate the role of the support leg action in performance. Twelve male soccer players performed maximal instep kicks. Their motions and ground reaction forces were recorded by a motion capture system and a force platform. Moments and angular velocities of the support leg and pelvis were computed using inverse dynamics. In most joints of the support leg, the moments were not associated with or counteracting the joint motions except for the knee joint. It can be interpreted that the initial knee flexion motion counteracting the extension joint moment has a role to attenuate the shock of landing and the following knee extension motion associated with the extension joint moment indirectly contributes to accelerate the swing of kicking leg. Also, appreciable horizontal rotation of the pelvis coincided with increase of the interaction moment due to the hip joint reaction force on the support leg side. It can be assumed that the interaction moment was the main factor causing the pelvis counterclockwise rotation within the horizontal plane from the overhead view that precedes a proximal-to-distal sequence of segmental action of the swing leg. Keywords: joint moment, interaction moment, angular velocity, pelvis rotation, three-dimensional

Introduction Among numerous types of kicks in soccer, the instep kicking is one of the most common techniques when a fast shot or long distance kick is required. Studies performed on instep kicking have mainly considered the kicking leg (Apriantono, Nunome, Ikegami, & Sano, 2006; Barfield, Kirkendall, & Yu, 2002; Dörge, Andersen, Sørensen, & Simonsen, 2002; Levanon & Dapena, 1998; Luhtanen, 1988; Nunome, Asai, Ikegami, & Sakurai, 2002; Nunome, Ikegami, Kozakai, Apriantono, & Sano, 2006; Rodano & Tavana, 1993). As a robust relationship exists between the foot velocity of the kicking leg immediately before ball impact and the resultant ball velocity (Andersen & Dörge, 2011; Asami & Nolte, 1983; Isokawa & Lees, 1988; Levanon & Dapena, 1998; Nunome, Lake, Georgakis, & Stergioulas, 2006), investigators have focused on mechanisms of how to achieve faster velocity of the distal end of the leg towards ball impact. Nunome, Ikegami, et al. (2006) illustrated the time-series data of the “motion-dependent” interaction moment (the moment due to other joint motions) together with those of the muscle

moment during kicking. They found that the lower leg angular acceleration immediately before ball impact was strongly influenced by the interaction moment due to the proximal end force. Given the proximal end force will be affected by support leg motion, it is important to examine the kinetic link between the kicking leg and the support leg (Lees, Asai, Andersen, Nunome, & Sterzing, 2010). While much is known about the joint dynamics of the kicking leg, that of the support leg has received little interest in the research literature (Lees et al., 2010). Lees, Steward, Rahmana, and Barton (2009) reported joint moments of the support leg during kicking. However, the information was mostly limited to the sagittal plane motion while the instep kicking is characterised by segmental and joint rotations in multiple planes (Kellis & Katis, 2007). The instep kick motion starts with an angled approach (Scurr & Hall, 2009). Pelvic rotation on the horizontal plane (Levanon & Dapena, 1998; Nunome et al., 2002), which coincides with support leg touch-down and a sequential rotational motion of the kicking leg, follows leading up to ball impact. From the point of view of dynamics, the support leg is the only body

Correspondence: Koichiro Inoue, Graduate School of Education and Human Development, Nagoya University, Nagoya, Japan. E-mail: [email protected] © 2014 Taylor & Francis

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part that receives external force (ground reaction force) reaching more than twice the kicker’s body weight (Katis & Kellis, 2010; Kellis, Katis, & Gissis, 2004; Orloff et al., 2008). Hence, the support leg has an important role during kicking: to resist the large external force in order to stabilise the body and to transfer mechanical energy to the proximal segment, thereby contributing to a proximal–distal sequential motion of the swing leg in indirect ways as suggested in the literature (Nunome & Ikegami, 2005; Putnam, 1991). We aimed to provide data which will describe the kinetic aspects of the support leg in detail as well as its essential functions during kicking. The purpose of the present study, therefore, was to illustrate the joint dynamics of the support leg during soccer instep kicking using a three-dimensional motion analysis. Methods Participants Twelve male experienced collegiate soccer players (age = 20.9 ± 0.5 years, height = 170.8 ± 5.3 cm, body mass = 69.0 ± 7.3 kg, soccer experience = 14.6 ± 1.3 years with a minimum of 12 years; mean ± SD) from a team in the regional top collegiate league, volunteered to participate in the present study. All participants preferred to kick the ball with their right leg. The experiment protocol was approved by the Human Research Committee of Nagoya University. Informed written consent was obtained from each participant before the experiment. Experimental protocols Kicking motions were captured using a 10-camera motion capture system (Vicon Nexus; Vicon Motion Systems, Oxford, UK) at 500 Hz. Ground reaction forces under support leg were also recorded simultaneously at 1000 Hz by a bare force platform (Type 9281E; Kistler Instruments, Winterthur, Switzerland) set at floor level. These were synchronised electrically within the Vicon Nexus software. Three-dimensional coordinates were expressed as a right-handed orthogonal reference frame fixed on the floor (Z was vertical and pointed upward; Y was horizontal and pointed in the direction of the target, while X was perpendicular to Y and Z). A FIFAapproved size 5 soccer ball (Jabulani Lushiada; ADIDAS Japan K.K., Tokyo, Japan) was used, and its inflation was controlled at 900 hPa. Participants wore the same type of rubber outsole soccer shoes (Del Mundo Wide TT; PUMA, Herzogenaurach, Germany), socks, a compressive shirt and shorts, although differing in size. Passive reflection markers (14 mm in diameter) were fixed

firmly by double-sided tape onto 21 body landmarks, including the toe, posterior side of the calcaneus, the lateral and medial malleolus, middle point of the shank, the lateral and medial epicondyle of femur, middle point of the thigh, the greater trochanter on the support leg and the kicking leg (for the kicking leg, fifth metatarsal head substituted for the toe), both sides of the anterior superior iliac spine and midpoint of the posterior superior iliac spine. Before kicking, a static posture of each participant was captured to record the relative position between each marker. Following this, markers on the medial side (the medial malleolus and the medial epicondyle of femur) were removed because these markers were unable to be tracked throughout the kicking motion. Additionally, eight markers were attached on the forward half of the lateral hemisphere of the ball, which the kicking foot would not have contact. After warm-up, the participants were instructed to perform maximum effort instep kicks of a stationary ball using their preferred leg (right). Kicks were performed towards a target which covered the goalmouth 6 m away. The approach run up was standardised to three steps. Participants were allowed to perform familiarised trials prior to testing. During these familiarised trials, investigators observed the relative support foot position on the force platform and adjusted the ball position so that participants would be able to step their support foot on the force platform during kicking. All participants performed 10 consecutive trials so that two successful shots for each participant (having a good foot–ball impact, the support leg foot position on the force platform and getting the centre region of the goal) could be selected for further analysis. Kinematic and kinetic procedure All parameters were processed using custom programs (Matlab; MathWorks, Natick, MA, USA). Hip joint centres were defined following the procedure described by Davis, Ounpuu, Tyburski, and Gage (1991), who developed a function to estimate hip joint centres using radiographic measurement data of pelvis and leg length data. The knee joint centres were defined as the midpoint between the lateral and medial epicondyle of femur. The ankle joint centres were defined as the midpoint between the lateral and medial malleolus. Those joint centres were directly estimated from temporary reference frames fixed on each segment assuming that the relative joint centre positions were not changed from the static posture. For calculating absolute angular velocity and angular acceleration of each segment with the method of Feltner and Nelson (1996), right-handed segmental reference frames fixed on each segment, Rf, Rs, Rt

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Support leg dynamics and Rp, were defined at the foot (Rf), shank (Rs) and thigh (Rt) on the support leg as well as pelvis (Rp). Each reference frame during analysis term was calculated from three non-collinear markers by using crossproduct. Rf fixed on the foot segment was calculated from the coordinates of the toe, heel and ankle joint centre. Rs and Rt were calculated from the coordinates of the hip, knee and ankle joint centre. Rs and Rt were fixed on the shank and thigh segments, respectively. Rp fixed on the pelvis segment was calculated from the coordinates of both the hip joint centres and the midpoint of posterior superior iliac spine. All reference frame vectors were normalised to unit length (Figure 1). The support leg was modelled as a linked segment model composed of the foot, shank, thigh and pelvis segment. Resultant joint moment vectors of each joint were calculated using inverse dynamics (Winter, 2009). Segment mass, centre of the mass location and moment of inertial values were derived from the data of young living Japanese athletes (Ae, Tang, & Yokoi, 1992), which was considered to be the most appropriate for the participants in the present study. The mass of the shoe (282–326 g) was added to the foot mass, and its effect on the length of radius gyration of the foot segment was assumed to be small enough to be negligible (Nunome et al., 2002). Ground reaction forces, free moments and centre of pressure were derived from the voltage data of the force platform. Those data originally sampled at 1000 Hz were re-sampled to 500 Hz to synchronise with the motion data. Using method similar to that reported by Sprigings, Marshall, Elliott, and Jennings (1994),

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the relative (joint) angular velocity vectors of the support leg ankle, knee and hip were calculated by subtracting absolute angular velocity vector of the distal segment from that of the adjacent proximal segment. According to the definition described by Nunome et al. (2002), both the resultant moment and the relative angular velocity vector of each joint were separated into orthogonal components using unit vectors included in anatomically relevant joint reference frames (rotation axes) defined at the ankle (Ra), knee (Rk) and hip (Rh) joints on the support leg (Figure 1). For the ankle joint, Za was a vector from the knee joint centre to the ankle joint centre, which represented the axis of ankle adduction (+) abduction (−). Xa was the vector product of Za and the vector from the heel to the toe, which represented the axis of ankle dorsal (+)/plantar flexion (−). Ya was the vector product of Za and Xa, which represented the axis of ankle inversion (+)/eversion (−). For the knee joint, Zk was a vector from the ankle joint centre to the knee joint centre, which represented the axis of knee external (+)/internal rotation (−). Xk was the vector product of Zk and the vector from the knee joint centre to the hip joint centre, which represented the axis of knee extension (+)/flexion (−). Yk was the vector product of Zk and Xk, which represented the axis of knee adduction (+)/addiction (−). For the hip joint, Zh was a vector from the knee joint centre to the hip joint centre, which represented the axis of hip external (+)/internal rotation (−). Xh was the vector product of the vector from the left hip joint centre to the right hip joint centre and Zh, which represented the axis of hip addiction (+)/adduction (−). Yh was the

Figure 1. Definition of reference frames. The segmental reference frames (left) were attached to the foot, shank, thigh and pelvis segment. The joint reference frames for rotation axes (right) were defined on the ankle, knee and hip joint.

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vector product of Zh and Xh, which represented the axis of hip flexion (+)/extension (−). These vectors were normalised to unit length. Of these nine joint rotational axes, seven degrees of freedom were defined on the support leg so that the resultant joint moment and angular velocity vectors were separated into three components at the ankle joint, one component at the knee joint and three components at the hip joint (Table I). In order to describe the influence of the support leg on the pelvis motion, we computed the moments acting from the support leg: the reaction hip joint moment and the moment due to the hip joint reaction force. The reaction hip joint moment was defined as a reversal moment of the hip joint moment. The moment due to the hip joint reaction force was defined as an interaction moment, which was computed by the cross-product of the moment arm (the vector from the middle point of both hip joint centres to the support leg hip joint centre) and the hip joint reaction force acting on pelvis segment (Figure 2). The same two moments were calculated on the kicking leg side as well. Lastly, all the four moments were decomposed into the Zp axis, which defined a normal vector to the pelvic plane formed by both hip joint centres and the midpoint of posterior superior iliac spine (i.e. a yaw axis of the pelvis segment). The angular velocity of the pelvis segment was also computed as the rate of rotation about the Table I. Direction of joint reference frames and anatomical rotation for joint moment and angular velocity. Joint reference frame

Rotation axis

Positive (+)

Xa

Dorsal flexion

Ya Za

Inversion Adduction

Planter flexion Eversion Abduction

Knee joint (Rk)

Xk

Extension

Flexion

Hip joint (Rh)

Xh Yh Zh

Adduction Flexion External rotation

Abduction Extension Internal rotation

Ankle joint (Ra)

Negative (−)

Figure 2. Explanation of the parameters for calculating interaction moment due to hip joint reaction force.

Zp axis. Counter-clockwise rotation from the overhead view corresponded to the positive direction (+) for the angular velocity and moments. All the moment, angular velocity and ground reaction force data were calculated from the raw threedimensional coordinate data and/or the raw force platform data. The joint moment data were then smoothed using a fourth-order Butterworth low-pass filter with a cut-off of frequency of 25 Hz. For the kicking leg side moment data, we used the procedure applied in the previous study (Nunome, Ikegami, et al., 2006); that is, we extrapolated the signal after ball impact prior to smoothing. We decided that this was an optical procedure to avoid ball impact artefact in the present study. On the other hand, the angular velocity and the ground reaction force data apparently had little noisy oscillations enough quality to be available. For this reason, we judged that it was not necessary to smooth angular velocity and the ground reaction force data. According to the definition described by Lees et al. (2009), the instant of the touch-down of the support leg was determined from the ground reaction data and was defined as occurring when the vertical force had exceeded 20 N. Shinkai, Nunome, Isokawa, and Ikegami (2009) reported that the target edge of the ball (i.e. opposite side to where the foot struck the ball) began to move forward 2 ms after the instance of contact between the foot and the ball. Thus, the instance of ball impact was determined as 2 ms before the instant when the captured ball marker visually showed a clear onset of forward movement on the software of the motion capture. The period from the touch-down of the support leg to ball impact was normalised to 100%. To illustrate the data before the touch-down, the analysed portion was expanded to –50% using the same scaling factor for normalisation. For instance, if the total time from the touch-down to the ball impact is 0.10 s, the start point of the data will be 0.05 s before the touchdown. The period from –50% to 0% (before the touch-down) and that from 0% to 100% (from the touch-down to the ball impact) were termed flight phase and support phase, respectively (Figure 3).

Figure 3. Definition of the normalised time period during kicking.

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For calculating ball velocity, the geometrical centre of the ball was estimated from the ball markers by a least-squares technique assuming each marker was positioned the same distance from the ball centre. As typical ball contact time is less than 10 ms (Nunome, Lake et al., 2006; Shinkai et al., 2009), the initial ball velocity was calculated using the ball centre displacements in available airborne frames, starting from 10 ms after the instance of initial foot–ball contact. The forward and lateral components of the ball velocity were calculated as the first derivative of linear regression lines fitted to their non-filtered displacement, and the vertical component was calculated as the first derivative of a quadratic regression line with its second derivative set equal to –9.81 m · s−2 fitted to its non-filtered displacement (Nunome et al., 2002). The absolute magnitude of the ball velocity was calculated from the value of its components. In the present study, calculation for all parameters was performed on each trial (a total of 24 kicks), and then the values were used to compute discrete mean, SD and ensemble average curves.

Results The average resultant ball velocity was 26.6 ± 1.5 m · s−1. Figure 4 shows the average value (±SD) of the joint moments and angular velocities of the ankle joint for the support leg. As shown, the ankle experienced a rapid multiaxial motion, which did not accompany the action of the joint moments. From the approximate instant of the touch-down, the ankle was rapidly forced into plantarflexion and inversion. Right thereafter, the ankle was forced into opposite directions: dorsal flexion and eversion. From the earlier part of the support phase (25%), consistent abduction motion appeared towards the ball impact. Meanwhile, the ankle joint moments counteracted the ankle joint motions, in which the plantarflexion and inversion moments appeared while the dorsal flexion and eversion motions were occurring. Moreover, a slight adduction moment was seen from the earlier part of the support phase (25%) when the abduction motion was occurring. Figure 5 shows the average value (±SD) of the joint moment and angular velocity of the knee for the support leg. The joint moment counteracted the joint motion for most of the movement, except for the phase immediately before ball impact (after 75% of the time). During the flight phase, the flexion moment was dominant while the support leg knee was extending towards touch-down. Soon after the touch-down, the knee joint moment developed a large extension moment while the knee was flexing. Immediately before ball impact, the knee came to

Figure 4. The average value (±SD) of the joint moment and angular velocity at the ankle joint of the support leg: dorsal flexion/plantarflexion (top), inversion/eversion (middle) and adduction/abduction (bottom).

extend again while the extension moment remained reasonably constant. Figure 6 shows the average value (±SD) of the joint moments and angular velocities of the hip for the support leg. All through the flight and support phases, the hip constantly exhibited an extension moment. Meanwhile, hip extension motion was maintained for all but the earlier part of the support phase (25–50%). Although there was a noteworthy adduction angular velocity increase during the middle of the support phase (around 50%), the joint moment was not substantially large. From the instant of touch-down, the hip was rapidly forced into external rotation while a slight internal rotation moment was exhibited.

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Figure 5. The average value (±SD) of the joint moment and angular velocity at the knee joint of the support leg: extension/ flexion.

Subsequently, a noteworthy internal hip rotation appeared from the earlier part of the support phase (0–25%), while still generating a slight internal hip rotation moment. The average curve (±SD) of mediolateral, anteroposterior and vertical ground reaction forces on the support leg is presented in Figure 7. There were clear, simultaneous onsets of lateral (towards the support leg side), posterior and vertical upward force from the instant of touch-down. Of the three components, the upward force was the largest and showed the steepest increase, reaching its peak magnitude swiftly (around 10%) and remaining at roughly the same magnitude towards ball impact. The lateral force showed a rather steeper increase than the posterior force, but their magnitudes were reasonably similar. Figure 8 shows the average value (±SD) of the pelvis rotation angular velocity and the four moments associated with pelvis rotation. There was a clear onset of pelvis counter-clockwise rotation from the instant of touch-down. After reaching its peak magnitude during the mid support phase, the angular velocity decreased during the latter half of the support phase. On the support leg side, the interaction moment rapidly increased after touch-down and acted in the counterclockwise direction during the entire support phase. In contrast, the reaction hip joint moment began to act on the clockwise direction from the mid support phase (around 50%). On the kicking leg side, those two moments initially acted on the clockwise direction and then began to act on the counter-clockwise direction after the mid support phase.

Discussion Support leg kinetics To date, there is only one study (Lees et al., 2009) that showed the joint moments of the support leg

Figure 6. The average value (±SD) of the joint moment and angular velocity at the hip joint of the support leg: adduction/ abduction (top), extension/flexion (middle) and external rotation/ internal rotation (bottom).

during kicking. However, the study solely reported those parameters as one-axial rotation motion (i.e. extension/flexion and dorsal/plantar flexion). Thus, of the variables obtained in the present study, the data for ankle dorsal/plantar flexion, knee extension/ flexion and hip extension/flexion were comparable to those of the study of Lees et al. (2009). Overall, the general patterns of the joint moments and angular velocities were similar between the two studies; however, in the study of Lees et al. (2009), ankle plantar flexion began before the support leg contacted with the ground. Lees et al. (2009) suggested this

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Support leg dynamics

Figure 8. The average value (±SD) of the pelvis segment angular velocity and the four moments acting on the pelvis: the pelvis segment angular velocity (top), the moments of the support leg side (middle) and that of the kicking leg side (bottom). Figure 7. The average value (±SD) of the ground reaction force: medial/lateral (top), anterior/posterior (middle) and vertical upward/downward (bottom).

indicated there was a premeditated motion to prepare for support leg landing. In contrast, in the present study, a sudden plantarflexion of the ankle joint appeared from the instant of the touch-down. The influence of the smoothing procedures may explain that discrepancy between the two studies. For investigating this issue, the present data of the ankle joint motion were re-sampled (250 Hz) and smoothed by a 12 Hz Butterworth filter to resemble the condition

applied in the Lees et al. (2009) study. Figure 9 shows the raw (same as Figure 4) and the smoothed data. These data highlight that pseudo ankle plantar flexion motion prior to the touch-down was created by the re-sampling and smoothing process. The present study has demonstrated and confirmed that there is little ankle pre-motion before the touch-down. For the joint moments about the coronal, transversal joint axes, there are no data available in the literature for comparison. A rapid ankle inversion/eversion and hip external rotation motions appear instantaneously after the touch-down. In contrast, these joints exhibited negligible amount or contrary joint moments in

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K. Inoue et al. extensors of the support leg were exhibiting concentric contraction during this phase. Those muscle activations most likely serve to lift the body and contribute to produce the linear upward acceleration of the hip joint on the kicking leg side. Practically, in order to achieve a fluent action of the motion-dependent interaction moment acting on the kicking leg, lifting the whole body upward by the support leg motion would be an effective action, particularly during the final phase of kicking.

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Dynamic interaction between the support leg and pelvis

Figure 9. Comparison of the dorsal flexion/plantarflexion angular velocity at the ankle joint calculated from two different procedures: raw data (500 Hz), and re-sampled (250 Hz) and filtered data (12 Hz cut-off frequency).

relation to these motions. It is logical to assume that these rapid motions were triggered by the impact peak of the ground reaction force typically seen in the first 25% after the touch-down (see Figure 7). Previous studies reported the support leg received large ground reaction forces in excess of two times body weight (Katis & Kellis, 2010; Kellis et al., 2004; Orloff et al., 2008), and a similar result was confirmed in the present study as well. Therefore, it is reasonable to generally speculate that the support leg has two major roles during kicking: (1) to resist the large external force in order to stabilise the body and/or (2) to transfer the mechanical energy to the proximal segment, thereby contributing to a proximal–distal sequential motion of the swing leg. The former could be characterised by negative power due to joint moments, and the latter could be extracted by positive power due to joint moments. In most joints of the support leg, the joint moments were not associated or counteracting the joint motions. As the ankle joint never exhibited positive power throughout the support phase, it can be interpreted that this joint works exclusively for absorbing the large external force from the ground. This seems very reasonable given the ankle is the most distal joint and will receive the ground reaction forces first. Immediately before ball impact the knee extension motions came to be associated with the knee extension joint moments, thereby producing a distinctive positive power. Nunome and Ikegami (2005) demonstrated that linear upward acceleration of the hip joint on the kicking leg side induces a motion-dependent interaction moment for accelerating the lower leg swing during the final phase of kicking. In the present study, the positive power due to the knee extension moments was seen on the support leg just before the ball impact, suggesting the knee

Pelvis rotation is typically seen in the mature instep kicking style, and its importance has been described in previous studies (Roberts & Metcalf, 1968; Wickstrom, 1975). It has been characterised that the rotation of the pelvis about the support leg precedes a proximal-to-distal sequence of segmental action of the swing limb. Of multi-axial rotational motion (Lees et al., 2009; Levanon & Dapena, 1998), the horizontal rotation has been considered to enhance protraction of the kicking leg side of pelvis (Lees & Nolan, 1998). Although it has been assumed that joint moments and/or the ground reaction force (Andersen & Dörge, 2011) most likely regulate the pelvis rotation, major kinetic sources that induced the horizontal rotation had not been clarified. The present study was, therefore, the first study that described the dynamic interaction between the support leg and pelvis. It can be seen that the angular velocity of the pelvis did not exhibit a marked change before the touch-down. A sudden transition of the pelvis angular velocity was observed from the instant of touch-down of the support leg after which angular velocity continued to increase until the middle of the support phase. This motion coincided with a clear increase of the interaction moment of the support leg side, while there were no appreciable changes for the other moments. As the touch-down of support leg seemed to trigger the rapid pelvis rotation, the joint reaction force of support leg side attributing to the ground reaction force was the most dominant factor to induce this counter-clockwise pelvis rotation. After the mid support phase, the angular velocity of the pelvis decreased while the interaction moment of the support leg side still maintained a distinctive positive value. From the onset of decrease of the pelvis angular velocity, the reaction hip joint moment on the support leg side began to generate a clockwise moment. Nunome, Ikegami et al. (2006) indicated that the deceleration of the kicking leg thigh typically seen in the proximal-todistal sequences was initiated by the kicking leg knee joint moment acting on the thigh. The result of the present study falls in line with the result of Nunome, Ikegami, et al. (2006) for the cause of

Support leg dynamics

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kick leg thigh deceleration. The result of the present study indicated the hip joint moment of support leg sides acting on the pelvis initiated the deceleration of the pelvis rotation, thereby forming the apparent proximal-to-distal sequence of segmental action from the pelvis to the kicking foot. In the present study, we clarified several critical functions of the support leg within a stable ball kicking condition and skilled homogeneous cohort. Future studies which examine these functions in unstable conditions (e.g. kicking a moving ball) or different skill level cohort are warranted. Further, this assessment should also include evaluation within-individual patterns as, at certain joints, some individuals seemed to optimise their motions in slightly different ways. Conclusions It can be concluded that (1) drastic ankle plantar flexion, ankle inversion/eversion motions and hip external rotation appearing just after the support leg touch-down were most likely triggered by the impact peak of the ground reaction force; (2) most joint moments produced at the ankle, knee and hip joints do not generate positive power, thereby having a role to absorb the shock of the landing; (3) knee extension motions immediately before ball impact were accompanied by those extension joint moments and would contribute to acceleration of the swing of kicking leg; and (4) the interaction moment due to the hip reaction force of support leg side attributing to the ground reaction force was the main factor in producing counter-clockwise rotation of the pelvis from the overhead view (rotation around the yaw axis) that precedes a proximal-to-distal sequence of segmental action of the swing leg. Acknowledgement The authors thank Dr. Kevin Ball at Victoria University for his great help in preparing this manuscript. References Ae, M., Tang, H., & Yokoi, T. (1992). Estimation of inertial properties on the body segments in Japanese athletes. Biomechanism, 11, 23–33. Andersen, T. B., & Dörge, H. C. (2011). The influence of speed of approach and accuracy constrain on the maximal speed of the ball in soccer kicking. Scandinavian Journal of Medicine & Science in Sports, 21(1), 79–84. doi:10.1111/j.16000838.2009.01024.x Apriantono, T., Nunome, H., Ikegami, Y., & Sano, S. (2006). The effect of fatigue on instep kicking kinetics and kinematics in association football. Journal of Sports Sciences, 24(9), 951– 960. doi:10.1080/02640410500386050

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Asami, T., & Nolte, V. (1983). Analysis of powerful ball kicking. In H. Matsui & K. Kobayashi (Eds.), Biomechanics VIII-B (pp. 695–700). Champaign, IL: Human Kinetics. Barfield, W. R., Kirkendall, D. T., & Yu, B. (2002). Kinematic instep kicking differences between elite female and male soccer players. Journal of Sports Science & Medicine, 3, 72–79. Davis, R., Ounpuu, S., Tyburski, D., & Gage, J. (1991). A gait analysis data collection and reduction technique. Human Movement Science, 10, 575–587. doi:10.1016/0167-9457(91) 90046-Z Dörge, H. C., Andersen, T. B., Sørensen, H., & Simonsen, E. B. (2002). Biomechanical differences in soccer kicking with the preferred and the non-preferred leg. Journal of Sports Sciences, 20(8), 293–299. doi:10.1080/026404102753576062 Feltner, M. E., & Nelson, S. T. (1996). Three-dimensional kinematics of the throwing arm during the penalty throw in water polo. Journal of Applied Biomechanics, 12(3), 347–372. Isokawa, M., & Lees, A. (1988). A biomechanical analysis of the instep kick motion in soccer. In T. Reilly, A. Lees, K. Davies, & W. J. Murphy (Eds.), Science & football (pp. 449–455). London: E & FN Spon. Katis, A., & Kellis, E. (2010). Three-dimensional kinematics and ground reaction forces during the instep and outstep soccer kicks in pubertal players. Journal of Sports Sciences, 28(11), 1233–1241. doi:10.1080/02640414.2010.504781 Kellis, E., & Katis, A. (2007). Biomechanical characteristics and determinants of instep soccer kick. Journal of Sports Science & Medicine, 6, 154–165. Kellis, E., Katis, A., & Gissis, I. (2004). Knee biomechanics of the support keg in soccer kicks from three angle of approach. Medicine & Science in Sports & Exercise, 36(6), 1017–1028. doi:10.1249/01.MSS.0000128147.01979.31 Lees, A., Asai, T., Andersen, T. B., Nunome, H., & Sterzing, T. (2010). The biomechanics of kicking in soccer: A review. Journal of Sports Sciences, 28(8), 805–817. doi:10.1080/ 02640414.2010.481305 Lees, A., & Nolan, L. (1998). The biomechanics of soccer: A review. Journal of Sports Sciences, 16(3), 211–234. doi:10.1080/ 026404198366740 Lees, A., Steward, I., Rahmana, N., & Barton, G. (2009). Lower limb function in the maximal instep kick in soccer. In T. Reilly & G. Atkinson (Eds.), Contemporary sport, leisure & ergonomics (pp. 149–159). London: Routledge. Levanon, J., & Dapena, J. (1998). Comparison of the kinematics of the full-instep kick and pass kicks in soccer. Medicine & Science in Sports & Exercise, 30(6), 917–927. doi:10.1097/ 00005768-199806000-00022 Luhtanen, P. (1988). Kinematics and kinetics of maximal instep kicking in junior soccer players. In T. Reilly, A. Lees, K. Davies, & W. J. Murphy (Eds.), Science & football (pp. 441– 448). London: E & FN Spon. Nunome, H., Asai, T., Ikegami, Y., & Sakurai, S. (2002). Threedimensional kinetic analysis of side-foot and instep soccer kicks. Medicine & Science in Sports & Exercise, 34(12), 2028– 2036. doi:10.1249/01.MSS.0000039076.43492.EF Nunome, H., & Ikegami, Y. (2005). The effect of hip linear motion on lower leg angular velocity during soccer instep kicking. In Q. Wang (Ed.), Proceedings of the XXIIIrd Symposium of the International Society of Biomechanics in Sports (pp. 770–772). Beijing: The People Sports Press. Nunome, H., Ikegami, Y., Kozakai, R., Apriantono, T., & Sano, S. (2006). Segmental dynamics of soccer instep kicking with the preferred and non-preferred leg. Journal of Sports Sciences, 24(5), 529–541. doi:10.1080/02640410500298024 Nunome, H., Lake, M., Georgakis, A., & Stergioulas, L. K. (2006). Impact phase kinematics of instep kicking in soccer. Journal of Sports Sciences, 24(1), 11–22. doi:10.1080/ 02640410400021450

1032

K. Inoue et al.

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Orloff, H., Sumida, B., Chow, J., Habibi, L., Fujino, A., & Kramer, B. (2008). Ground reaction forces and kinematics of plant leg position during instep kicking in male and female collegiate soccer players. Sports Biomechanics, 7(2), 238–247. doi:10.1080/14763140701841704 Putnam, C. A. (1991). A segment interaction analysis of proximalto-distal sequential segment motion patterns. Medicine & Science in Sports & Exercise, 23(1), 130–144. doi:10.1249/ 00005768-199101000-00019 Roberts, E. M., & Metcalf, A. (1968). Mechanical analysis of kicking. In J. Wartenweiller, E. Jokl, & M. Hebbelink (Eds.), Biomechanics I (pp. 315–319). Basel: Karger. Rodano, R., & Tavana, R. (1993). Three-dimensional analysis of instep kick in professional soccer players. In T. Reilly, J. Clarys, & A. Stibbe (Eds.), Science & football II (pp. 441–448). London: E & FN Spon.

Scurr, J., & Hall, B. (2009). The effects of approach angle on penalty kicking accuracy and kick kinematics with recreational soccer players. Journal of Sports Sciences & Medicine, 8, 230–234. Shinkai, H., Nunome, H., Isokawa, M., & Ikegami, Y. (2009). Ball impact dynamics of instep soccer kicking. Medicine & Science in Sports & Exercise, 41(4), 889–897. doi:10.1249/ MSS.0b013e31818e8044 Sprigings, E., Marshall, R., Elliot, B., & Jennings, L. (1994). A three-dimensional kinematic method for determining the effective of arm segment rotations in producing racquet-head speed. Journal of Biomechanics, 27(3), 245–254. Wickstrom, R. L. (1975). Developmental kinesiology. Exercise & Sports Science Reviews, 3, 163–192. Winter, D. A. (2009). Biomechanics and motor control of human movement (4th ed.). Hoboken, NJ: John Wiley & Sons.