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1.
Kinematic comparison of the preferred and non-preferred foot punt kick   总被引：1，自引：1，他引：0  
Kicking with the non-preferred leg is important in Australian Football and becoming important in the rugby codes. The aim of this study was to examine differences between preferred and non-preferred leg kicking in the drop punt kick. Seventeen elite Australian Football players performed kicks with the preferred and non-preferred leg. Optotrak Certus collected kinematic data of the kick leg and pelvis (200 Hz) from kick leg toe-off until ball contact. Foot speed, knee and shank angular velocity at ball contact, and pelvis range of motion were significantly larger for the preferred leg (P < 0.05). In contrast, hip and thigh angular velocity at ball contact and hip range of motion were significantly larger for the non-preferred leg. This indicates different movement patterns, with preferred-leg kicks making greater use of the pelvis, knee, and shank while non-preferred leg kicks rely relatively more on the hip and thigh (P < 0.05). Reasons for this difference might be due to locking degrees of freedom or sub-optimal sequencing in the non-preferred leg. The thigh-knee continuum identified by Ball ( 2008 ) was also evident in this study. Findings have implications for training non-preferred leg kicking for performance and injury prevention.  相似文献   

2.
In Australian rules football structured increases in ball size during development end with the transition to the Size 5 (adult) ball at the Under-15 age group. This study assessed changes in kick technique and performance in experienced junior performers when using Size 4 and 5 Australian rules footballs. Participants (n = 22, 13.77 ± 0.61 years) performed drop punt kicks in 2 representative tasks; a Decision-Making Test (DMT) (n = 14) and Set-Shot Test (SST) (n = 14 + 8). Results indicate participants sustained their level of kick performance (accuracy and quality of ball spin) in both tests when using a Size 5 football. Sustained kick performance in the DMT primarily resulted from adaptations to time-point technical measures at ball release. No significant differences were detected for technical measures between ball sizes in the SST. A dynamic kicking task (DMT) in combination with ball size manipulation may have placed greater demand on skill execution in comparison to a self-paced kicking task (SST). Results provide initial support for the utility of challenging representative dynamic and self-paced tasks, such as the DMT and SST used here for Australian football, for skill testing and practice in sport  相似文献   

3.
The aim of this study was to analyse the characteristics of the asymmetries in the dominant and non-dominant limbs when kicking stationary and rolling balls. Ten experienced Brazilian amateur futsal players participated in this study. Each participant performed kicks under two conditions (stationary ball vs. rolling ball) with the dominant and non-dominant limbs (five kicks per condition per limb). We analysed the kicking accuracy, ball and foot velocities, angular joint displacement and velocity. The asymmetry between the dominant and non-dominant limbs was analysed by symmetry index and two-way repeated measures ANOVA. The results did not reveal any interaction between the condition and limb for ball velocity, foot velocity and accuracy. However, kicking with the dominant limb in both kicks showed higher ball velocity (stationary ball: dominant – 24.27 ± 2.21 m · s?1 and non-dominant – 21.62 ± 2.26 m · s?1; rolling ball: dominant – 23.88 ± 2.71 m · s?1 and non-dominant – 21.42 ± 2.25 m · s?1), foot velocity (stationary ball: dominant – 17.61 ± 1.87 m · s?1 and non-dominant – 15.58 ± 2.69 m · s?1; rolling ball: dominant – 17.25 ± 2.26 m · s?1 and non-dominant – 14.77 ± 2.35 m · s?1) and accuracy (stationary ball: dominant – 1.17 ± 0.84 m and non-dominant – 1.56 ± 1.30 m; rolling ball: dominant – 1.31 ± 0.91 m and non-dominant – 1.97 ± 1.44 m). In addition, the angular joint adjustments were dependent on the limb in both kicks (the kicks with non-dominant limb showed lower hip external rotation than the kicks with the dominant limb), indicating that the hip joint is important in kick performance. In conclusion, the kicks with the non-dominant limb showed different angular adjustments in comparison to kicks with the dominant limb. In addition, kicking a rolling ball with the non-dominant limb showed higher asymmetry for accuracy, indicating that complex kicks are more asymmetric.  相似文献   

4.
In the collision between a striking implement and ball, the term “sweet spot” represents the impact location producing best results. In football kicking, it is not known if a sweet spot exists on the foot because no method to measure impact location in three-dimensional space exists. Therefore, the aims were: (1) develop a method to measure impact location on the foot in three-dimensional space; (2) determine if players impacted the ball with a particular location; (3) determine the relationship between impact location with kick performance; (4) discuss if a sweet spot exists on the foot. An intra-individual analysis was performed on foot-ball impact characteristics of ten players performing 30 Australian football drop punt kicks toward a target. (1) A method to measure impact location was developed and validated. (2) The impact locations were normally distributed, evidenced by non-significant results of the Shapiro-Wilk test (p > 0.05) and inspection of histograms, meaning players targeted a location on their foot. (3) Impact location influenced foot-ball energy transfer, ball flight trajectory and ankle plantar/dorsal flexion. (4) These results indicate a sweet spot exists on the foot for the Australian football drop punt kick. In conclusion, the impact location is an important impact characteristic.  相似文献   

5.
This paper describes the use of Pareto-optimal solutions for the screw kick in rugby. We attempted to optimise the initial conditions for a screw kick. The optimisation was carried out using an elitist non-dominated sorting genetic algorithm. Distance achieved in flight is considered as an objective function, as well as the lateral deviation between the ball and the touchline, or the flight time. Six initial conditions were defined as control parameters: the magnitude of the velocity vector, the flight path angle, the azimuth angle, the spin rate, the pitch angle and the yaw angle. The results are summarised as follows: it is impossible for both objective functions to be satisfied simultaneously, although the greatest distance achieved in flight and the smallest value of the lateral deviation between the ball and the touchline, or the least flight time, is the ideal situation. This kind of conflicting solution is called a ‘Pareto-optimal solution’. The optimal kick in Pareto-optimal solutions made by the leg nearest the touchline produces a greater flight distance than the optimal kick in Pareto-optimal solutions made using the leg furthest from the touchline. The initial pitch angle, which is the angle between the longitudinal axis of the ball and the horizontal plane, should be comparable to or slightly greater than the initial flight path angle in order to satisfy the Pareto-optimal solutions.  相似文献   

6.
Flight dynamics of the screw kick in rugby   总被引：1，自引：1，他引：0  
This paper describes the aerodynamic forces and the flight trajectory for the screw (spiral) kick in rugby. The screw kick is defined as that which causes the ball to spin on its longitudinal axis. The aerodynamic forces acting on a rugby ball spinning on its longitudinal axis were measured in a wind tunnel using a six-component strut type balance. It was found that the drag, the lift and the pitching moment depend on the angle of attack, while the side force (Magnus force) depends on both the spin rate and the angle of attack in the range where the wind speed lies between 15 and 30 m s-1 and the spin rate is between 1 and 10 revolutions per second. Moreover, the flight trajectory was obtained by integrating the full nonlinear six degrees of freedom equations of motion on the basis of aerodynamic data. In a simulation, a ball spinning on its longitudinal axis tended to hook toward or away from the touchline even if the velocity and angular velocity vectors were parallel to the touchline. The direction of the hook depends on the direction of the angular velocity vector. The initial direction of the hook depends on the relationship between the flight path angle and the pitch angle as well as the direction of the angular velocity vector.  相似文献   

7.
This study involved a theoretical and an experimental investigation of the direct free kick in soccer. Our aim was to develop a mathematical model of the ball's flight incorporating aerodynamic lift and drag forces to explore this important 'set-play'. Trajectories derived from the model have been compared with those obtained from detailed video analysis of experimental kicks. Representative values for the drag and lift coefficients have been obtained, together with the implied orientation of the ball's spin axis in flight. The drag coefficient varied from 0.25 to 0.30 and the lift coefficient from 0.23 to 0.29. These values, used with a simple model of a defensive wall, have enabled free kicks to be simulated under realistic conditions, typical of match-play. The results reveal how carefully attackers must engineer the dynamics of a successful kick. For a central free kick some 18.3 m (20 yards) from goal with a conventional wall, and initial speed of 25 m·s?1, the ball's initial elevation must be constrained between 16.5° and 17.5° and the ball kicked with almost perfect sidespin.  相似文献   

8.
The purpose of this study was to determine whether joint velocities and segmental angular velocities are significantly correlated with ball velocity during an instep soccer kick. We developed a deterministic model that related ball velocity to kicking leg and pelvis motion from the initiation of downswing until impact. Three-dimensional videography was used to collect data from 16 experienced male soccer players (age = 24.8 ± 5.5 years; height = 1.80 ± 0.07 m; mass = 76.73 ± 8.31 kg) while kicking a stationary soccer ball into a goal 12 m away with their right foot with maximal effort. We found that impact velocities of the foot center of mass (CM), the impact velocity of the foot CM relative to the knee, peak velocity of the knee relative to the hip, and the peak angular thigh velocity were significantly correlated with ball velocity. These data suggest that linear and angular velocities at and prior to impact are critical to developing high ball velocity. Since events prior to impact are critical for kick success, coordination and summation of speeds throughout the kicking motion are important factors. Segmental coordination that occurs during a maximal effort kick is critical for completing a successful kick.  相似文献   

9.
The three-dimensional kinematics of international female footballers performing a simulated direct free kick (curve kick) were compared with those of an instep kick. Reflective markers attached to the participants were tracked by 17 Vicon cameras sampling at 250 Hz. Foot velocity at ball impact did not differ between the two types of kick, but the way in which foot velocity was generated did differ, with instep kicks using a faster approach velocity and greater linear velocities of the hip and knee, and curve kicks using a greater knee angular velocity at impact. In both types of kick, peak knee angular velocity and peak ankle linear velocity occurred at ball impact, providing biomechanical support to the common coaching recommendation of kicking through the ball. To achieve a curved ball trajectory, players should take a wide approach angle, point the support foot to the right of the intended target (for right-footed players), swing the kicking limb across the face of the goal, and impact the ball with the foot moving upwards and in an abducted position. This information will be useful to coaches and players in identifying the fundamental coaching points necessary to achieve a curved trajectory of the ball compared with the more commonly described instep kick kinematics.  相似文献   

10.
Abstract

The location and outcome of all free kicks taken directly at goal in the 2007 women's football World Cup were assessed to identify areas with the most goal-scoring potential and assist with tactical decisions and training design. Video of all free kicks taken directly at goal in the 32 games was captured and the location of the ball on the pitch was calculated from pitch markings and image pixel coordinates using a customized curve-fitting method. The outcome of each free kick was determined and for those that resulted in a goal or were saved, information on ball flight time and the placement of the ball relative to the goal was reported. All seven free kicks that resulted in a goal were taken from a central area within 7 m of the penalty circle, placed at the edge of the goal within approximately 1 m of the goalpost, and had an average flight time of 1.09 s, which was significantly faster than for those that were saved. All free kicks directed towards the bottom and centre of the goal resulted in straightforward saves for the goalkeeper. It is recommended that teams should consider a direct shot from free kicks awarded within 7 m of the penalty circle. For free kicks from wide areas and areas further from the goal, players should be aware of their individual ability and only take a shot when they perceive the probability of scoring a goal to be high. Otherwise, alternative attacking strategies should be considered to avoid an easy turnover of possession.  相似文献   

11.
Abstract

The current investigation aimed to determine whether there are differences in ball velocity and 3D kinematics when performing maximal kicks with the dominant and non-dominant limbs. Seventeen male academy soccer players performed maximal speed place kicks with their dominant and the non-dominant limbs. The 3D kinematics of the lower extremities were obtained using a 10-camera motion capture system operating at 500 Hz. Hip, knee and ankle joint kinematics were quantified in the sagittal, coronal and transverse planes and then contrasted using paired t-tests. Significantly higher ball velocities were obtained with the dominant limb. Foot linear velocity and knee extension velocity at ball contact were also found to be significantly greater in the dominant limb. That reduced ball velocities were observed between kicking limbs highlights the potential performance detriments that may occur when kicking with the non-dominant limb; thus, it is recommended that additional bilateral training be undertaken in order to attenuate this and improve overall kicking performance.  相似文献   

12.
Place kicks in Rugby Union present valuable opportunities to score points outside the spatiotemporal dynamics of open play but are executed under varying performance constraints. We analysed effects of specific task constraints and relevant contextual factors on place kick performance in the 2015 Rugby Union World Cup. Data were collected from television broadcasts for each place kick. In addition to kick outcomes, contextual factors, including time of the kick in the match, score margin at the time of the kick, and outcome of the kicker’s previous kick, were recorded. Effects of spatial task constraints were analysed for each kick, using distance (m) and angle (°) of the kick to the goalposts. A binomial logistic regression model revealed that distance from, and angle to, the goalposts were significant predictors of place kick outcome. Furthermore, the success percentage of kickers who missed their previous kick was 7% lower than those who scored their previous kick. Place kick success percentage in the 10 minutes before half-time was 8% lower than the mean tournament success percentage, which was 75% (95% CI 71–78%). The highest kick success percentage was recorded when scores were level (83%; 95% CI 72–91%). Our data highlighted how subtle changes in task constraints and contextual factors can influence performance outcomes in elite performers in international competition. Fluctuations in place kick success suggested that individual constraints, such as thoughts, emotions and fatigue, induced during competition, could interact with perceptions to influence emergent performance behaviours.  相似文献   

13.
Abstract

The purpose of the present study was to compare the three-dimensional kinematics of the lower extremities and ground reaction forces between the instep kick and the kick with the outside area of the foot (outstep kick) in pubertal soccer players. Ten pubertal soccer players performed consecutive kicking trials in random order after a two-step angled approach with the instep and the outstep portion of the foot. Three-dimensional data and ground reaction forces were measured during kicking. Paired t-tests indicated significantly higher (P < 0.05) ball speeds and ball/foot speed ratios for the instep kick compared with the outstep kick. Non-significant differences in angular and linear sagittal plane kinematic parameters, temporal characteristics, and ground reaction forces between the instep and outstep soccer kicks were observed (P > 0.05). In contrast, analysis of variance indicated that the outstep kick displayed higher hip internal rotation and abduction, knee internal rotation, and ankle inversion than the instep kick (P < 0.05). Our results suggest that the instep kick is more powerful than the outstep kick and that different types of kick require different types of skill training.  相似文献   

14.
Modelling the flight of a soccer ball in a direct free kick   总被引：2，自引：0，他引：2  
This study involved a theoretical and an experimental investigation of the direct free kick in soccer. Our aim was to develop a mathematical model of the ball's flight incorporating aerodynamic lift and drag forces to explore this important 'set-play'. Trajectories derived from the model have been compared with those obtained from detailed video analysis of experimental kicks. Representative values for the drag and lift coefficients have been obtained, together with the implied orientation of the ball's spin axis in flight. The drag coefficient varied from 0.25 to 0.30 and the lift coefficient from 0.23 to 0.29. These values, used with a simple model of a defensive wall, have enabled free kicks to be simulated under realistic conditions, typical of match-play. The results reveal how carefully attackers must engineer the dynamics of a successful kick. For a central free kick some 18.3 m (20 yards) from goal with a conventional wall, and initial speed of 25 m x s(-1), the ball's initial elevation must be constrained between 16.5 degrees and 17.5 degrees and the ball kicked with almost perfect sidespin.  相似文献   

15.
The punt kick is a fundamental skill used in several team sports; however, there has been a lack of research on how fatigue affects its technique. The purpose of this study was to determine the effects of short-term fatigue on punt-kicking performance. Eight elite and sub-elite Australian Football players performed maximal drop punt kicks on their preferred leg prior to, during and after a match-specific fatigue protocol. Optotrak Certus collected kinematic data from kick foot toe-off until ball contact. Repeated-measures analysis of variance showed a significant increase in 20 m sprint times after each short-term protocol, indicating fatigue. Foot speed did not significantly change with fatigue; however, increases in the range of motion at the pelvis and kicking thigh, along with increases in kicking thigh angular velocity, occurred. For the support leg, maximum knee flexion angular velocity increased while there was greater flexion found at the knee and hip, and greater range of motion at the knee. Players are able to make kinematic adaptations in order to maintain foot speed while punting for maximal distance after short-term efforts.  相似文献   

16.
Abstract

This study examined the consistency of pre-performance routines in international rugby union goal kickers on kicks of varying difficulty and under different amounts of situational pressure. Concentration times and physical preparation times were calculated from video recordings of the 572 place kicks taken during the 1999 Rugby Union World Cup. In contrast to the view that performers should seek consistent pre-performance routine times, the results revealed a strong positive relationship between kick difficulty and concentration time. Analysis of the effect of situational pressure, determined by the difference in score before the kick, revealed that players tended to have longer concentration times and shorter physical preparation times when the scores were close. There were no differences between the best and worst kickers in the tournament on routine time, consistency or rhythmicity. The view that increasing the temporal consistency of a routine will result in improved performance is challenged.  相似文献   

17.
ABSTRACT

A possible link between soccer-specific injuries, such as groin pain and the action of hip adductor muscles has been suggested. This study aimed to investigate neuromuscular activation of the adductor magnus (AM) and longus (AL) muscles during instep and side-foot soccer kicks. Eight university soccer players performed the two types of kick at 50%, 75% and 100% of the maximal ball speed. Surface electromyography (EMG) was recorded from the AM, AL, vastus lateralis (VL) and biceps femoris (BF) muscles of both kicking and supporting legs and the kicking motions were three-dimensionally captured. In the kicking leg, an increase in surface EMG with an increase in ball speed during instep kicking was noted in the AM muscle (p < 0.016), but not in AL, VL or BF muscles (p > 0.016). In the supporting leg, surface EMG of both AM and AL muscles was significantly increased with an increase in the ball speed before ball impact during both instep and side-foot kicks (p < 0.016). These results suggest that hip adductor muscles markedly contribute to either the kicking or supporting leg to emphasise the action of soccer kicks.  相似文献   

18.
This study examined the consistency of pre-performance routines in international rugby union goal kickers on kicks of varying difficulty and under different amounts of situational pressure. Concentration times and physical preparation times were calculated from video recordings of the 572 place kicks taken during the 1999 Rugby Union World Cup. In contrast to the view that performers should seek consistent pre-performance routine times, the results revealed a strong positive relationship between kick difficulty and concentration time. Analysis of the effect of situational pressure, determined by the difference in score before the kick, revealed that players tended to have longer concentration times and shorter physical preparation times when the scores were close. There were no differences between the best and worst kickers in the tournament on routine time, consistency or rhythmicity. The view that increasing the temporal consistency of a routine will result in improved performance is challenged.  相似文献   

19.
Abstract

In taekwondo, the stance position can potentially affect kick performance. The aim of this study was to analyse mechanical variables in the roundhouse kick in taekwondo according to three stance positions (0°, 45°, 90°). Nine experienced taekwondo athletes performed consecutive kicking trials in a random order according to these three relative positions of the feet on the ground. Measurements for the mechanical analysis were performed using two 3D force plates and an eight-camera motion capture system. The taekwondo athletes’ reaction and execution times were shorter when starting from the 0° and 45° stance positions than from the 90° position (P < 0.05). Moreover, the ground reaction force was negatively correlated with execution time and positively with velocity of thigh and shank. Our results suggest that the stance position affects the execution technique of taekwondo athletes’ kicks. It is suggested that athletes should not adopt the 90° stance position because it will not enable them to achieve the best performance in the roundhouse kick.  相似文献   

20.
Impact is an important aspect of the kicking skill. This study examined foot and ball motion during impact and compared distance and accuracy punt kicks. Two-dimensional high-speed video (4000 Hz) captured data of the shank, foot and ball through impact of 11 elite performers kicking for maximal distance and towards a target 20 m in distance. Four phases were identified during impact, with an overall reduction in foot velocity of 5.0 m · s?1 (± 1.1 m · s?1) and increase in ball velocity of 22.7 m · s?1 (± 2.3 m · s?1) from the start to end of contact. Higher foot velocity was found in distance compared to accuracy kicks (22.1 ± 1.6 m · s?1 vs. 17.7 ± 0.9 m · s?1, P < 0.05), and was considered to produce the significant differences in all impact characteristics excluding foot-to-ball speed ratio. Ankle motion differed between the kicking tasks; distance kicks were characterised by greater rigidity compared to accuracy kicks evident by larger force (834 ± 107 N vs. 588 ± 64 N) and smaller change in ankle angle (2.2 ± 3.3° vs. 7.2 ± 6.4°). Greater rigidity was obtained by altering the position of the ankle at impact start; distance kicks were characterised by greater plantarflexion (130.1 ± 5.8° vs. 123.0 ± 7.9°, P < 0.05), indicating rigidity maybe actively controlled for specific tasks.  相似文献   

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