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1.
ABSTRACT

When executed correctly, swing bowling has the potential to influence the outcome of a cricket match, yet little is known about the required bowling action and ball flight characteristics. This study aimed to describe the bowling action and initial ball flight characteristics as well as to identify variables that may be associated with increased swing in pathway and high-performance medium and fast pace bowlers. A 17-camera Vicon motion analysis system captured retro-reflective markers placed on the upper-body of participants and new cricket balls to quantify bowling action and initial ball flight kinematics. Bowlers delivered the ball with their forearm and hand angled in the direction of intended swing with an extended wrist flexing through the point of ball release. Bowlers who produced more swing had increased seam stability, possibly linked to a lower wrist and ball angular velocity. It is believed that swing increases with seam stability, however, optimal ranges may exist for seam azimuth angle, ball angular velocity and release speed. These findings may assist coaches to optimise the performance of bowlers, however, future research should use bowlers who play at higher levels to investigate swing bowling at greater speeds.  相似文献   

2.
This modelling study sought to describe the relationships between elbow joint kinematics and wrist joint linear velocity in cricket fast bowlers, and to assess the sensitivity of wrist velocity to systematic manipulations of empirical joint kinematic profiles. A 12-camera Vicon motion analysis system operating at 250 Hz recorded the bowling actions of 12 high performance fast bowlers. Empirical elbow joint kinematic data were entered into a cricket bowling specific “Forward Kinematic Model” and then subsequently underwent fixed angle, angular offset and angle amplification manipulations. A combination of 20° flexion and 20° abduction at the elbow was shown to maximise wrist velocity within the experimental limits. An increased elbow flexion offset manipulation elicited an increase in wrist velocity. Amplification of elbow joint flexion–extension angular displacement indicated that, contrary to previous research, elbow extension range of motion and angular velocity at the time of ball release were negatively related to wrist velocity. Some relationships between manipulated joint angular waveforms and wrist velocity were non-linear, supporting the use of a model that accounts for the non-linear relationships between execution and outcome variables in assessing the relationships between elbow joint kinematics and wrist joint velocity in cricket fast bowlers.  相似文献   

3.
Cricket     
The laws of bowling in cricket state ‘a ball is fairly delivered in respect of the arm if, once the bowler's arm has reached the level of the shoulder in the delivery swing, the elbow joint is not straightened partially or completely from that point until the ball has left the hand’. Recently two prominent bowlers, under suspicion for transgressing this law, suggested that they are not ‘throwing’ but due to an elbow deformity are forced to bowl with a bent bowling arm. This study examined whether such bowlers can produce an additional contribution to wrist/ball release speed by internal rotation of the upper arm. The kinematics of a bowling arm were calculated using a simple two‐link model (upper arm and forearm). Using reported internal rotation speeds of the upper arm from baseball and waterpolo, and bowling arm kinematics from cricket, the change in wrist speed was calculated as a function of effective arm length, and wrist distance from the internal rotation axis. A significant increase in wrist speed was noted. This suggests that bowlers who can maintain a fixed elbow flexion during delivery can produce distinctly greater wrist/ball speeds by using upper arm internal rotation.  相似文献   

4.
In order to get bounce and movement seam bowlers need to bowl the ball “into” the pitch. Standard deliveries by elite players are typically projected at around 7° below horizontal. In contrast, young players currently often need to release the ball almost horizontally in an effort to get the ball to bounce close enough to the batter. We anticipated that shortening the pitch could be a simple way to help young bowlers to release the ball at a better angle and with more consistency. Twenty county or best in club age group under 10 and under 11 seam bowlers were analysed bowling indoors on two different pitch lengths. They were found to project the ball on average 3.4° further below horizontal on a 16 yard pitch compared with a 19 yard pitch, while ball speed and position at release changed negligibly. Pitch length did not affect the consistency of the release parameters. The shorter pitch led to a ball release angle closer to that of elite bowlers without changing release speed, and this should enable players to achieve greater success and develop more variety in their bowling.  相似文献   

5.
This study sought to identify kinematic differences in finger-spin bowling actions required to generate variations in ball speed and spin between different playing groups. A 12-camera Vicon system recorded the off-spin bowling actions of six elite and 13 high-performance spin bowlers, and the “doosra” actions of four elite and two high-performance players. Forearm abduction and fixed elbow flexion in the bowling arm were higher for the elite players compared with the high-performance players. The elite bowlers when compared with the high-performance players delivered the off-break at a statistically significant higher velocity (75.1 and 67.1 km/hr respectively) and with a higher level of spin (26.7 and 22.2 rev/s respectively). Large effect sizes were seen between ball rotation, pelvic and shoulder alignment rotations in the transverse plane. Elbow extension was larger for elite bowlers over the period upper arm horizontal to ball release. Compared to the off-break, larger ranges of shoulder horizontal rotation, elbow and wrist extension were evident for the “doosra”. Furthermore, the “doosra” was bowled with a significantly longer stride length and lower ball release height. Although not significantly different, moderate to high effect size differences were recorded for pelvis rotation, elbow extension and elbow rotation ranges of motion.  相似文献   

6.
Kinematic studies have shown that fast bowlers have run-up velocities, based on centre of mass velocity calculations, which are comparable to elite javelin throwers. In this study, 34 fast bowlers (22.3 ± 3.7 years) of premier grade level and above were tested using a three-dimensional (3-D) motion analysis system (240 Hz). Bowlers were divided into four speed groups: slow-medium, medium, medium-fast, and fast. The mean centre of mass velocity at back foot contact (run-up speed) was 5.3 ± 0.6 m/s. Centre of mass velocity at back foot contact was significantly faster in the fastest two bowling groups compared to the slow-medium bowling group. In addition, stepwise multiple regression analysis showed that the centre of mass deceleration over the delivery stride phase was the strongest predictor of ball speed in the faster bowling groups. In conclusion, centre of mass kinematics are an important determinant of ball speed generation in fast bowlers. In particular, bowlers able to coordinate their bowling action with periods of centre of mass deceleration may be more likely to generate high ball speed.  相似文献   

7.
The laws of bowling in cricket state 'a ball is fairly delivered in respect of the arm if, once the bowler's arm has reached the level of the shoulder in the delivery swing, the elbow joint is not straightened partially or completely from that point until the ball has left the hand'. Recently two prominent bowlers, under suspicion for transgressing this law, suggested that they are not 'throwing' but due to an elbow deformity are forced to bowl with a bent bowling arm. This study examined whether such bowlers can produce an additional contribution to wrist/ball release speed by internal rotation of the upper arm. The kinematics of a bowling arm were calculated using a simple two-link model (upper arm and forearm). Using reported internal rotation speeds of the upper arm from baseball and waterpolo, and bowling arm kinematics from cricket, the change in wrist speed was calculated as a function of effective arm length, and wrist distance from the internal rotation axis. A significant increase in wrist speed was noted. This suggests that bowlers who can maintain a fixed elbow flexion during delivery can produce distinctly greater wrist/ball speeds by using upper arm internal rotation.  相似文献   

8.
Cricket bowling is traditionally thought to be a rigid-arm motion, allowing no elbow straightening during the delivery phase. Conversely, research has shown that a perfectly rigid arm through delivery is practically unattainable, which has led to rule changes over the past years. The current rule requires a bowler not to increase the elbow angle by more than 15°, thus requiring a measurement to confirm legality in “suspect” bowlers. The aims of this study were to evaluate whether the current rule is maintained over a range of bowlers and bowling styles, and to ascertain whether other kinematics measures may better differentiate between legal and suspect bowling actions. Eighty-three bowlers of varying pace were analysed using reflective markers and a high-speed (240 Hz) eight-camera motion analysis system in a laboratory. The change in elbow segment angle (minimum angle between the arm and forearm), the change in elbow extension angle with respect to the flexion–extension axis of a joint coordinate system, and the elbow extension angular velocity at ball release were measured. We found that bowlers generally bowled within a change in elbow extension angle of 15°. However, this limit was unable to differentiate groups of bowlers from those who were suspected of throwing in the past. Improved differentiation was attained using the elbow extension angular velocity at ball release. The elbow extension angular velocity at ball release may be conceptually more valid than the elbow extension angle in determining which bowlers use the velocity-contributing mechanisms of a throw. Also, a high value of elbow extension angular velocity at ball release may be related to the visual impression of throwing. Therefore, it is recommended that researchers and cricket legislators examine the feasibility of specifying a limit to the elbow extension angular velocity at ball release to determine bowling legality.  相似文献   

9.
Spin bowling is generally coached using a standard technical framework, but this practice has not been based upon a comparative biomechanical analysis of leg-spin and off-spin bowling. This study analysed the three-dimensional (3D) kinematics of 23 off-spin and 20 leg-spin bowlers using a Cortex motion analysis system to identify how aspects of the respective techniques differed. A multivariate ANOVA found that certain data tended to validate some of the stated differences in the coaching literature. Off-spin bowlers had a significantly shorter stride length (p = 0.006) and spin rate (p = 0.001), but a greater release height than leg-spinners (p = 0.007). In addition, a number of other kinematic differences were identified that were not previously documented in coaching literature. These included a larger rear knee flexion (p = 0.007), faster approach speed (p < 0.001), and flexing elbow action during the arm acceleration compared with an extension action used by most of the off-spin bowlers. Off-spin and leg-spin bowlers also deviated from the standard coaching model for the shoulder alignment, front knee angle at release, and forearm mechanics. This study suggests that off-spin and leg-spin are distinct bowling techniques, supporting the development of two different coaching models in spin bowling.  相似文献   

10.
ABSTRACT

The aim of this study was to identify the key kinematic parameters which contribute to higher spin rates in elite finger spin bowling. Kinematic data were collected for twenty-three elite male finger spin bowlers with thirty kinematic parameters calculated for each delivery. Stepwise linear regression and Pearson product moment correlations were used to identify kinematic parameters linked to spin rate. Pelvis orientation at front foot contact (r = 0.674, p < 0.001) and ball release (r = 0.676, p < 0.001) were found to be the biggest predictors of spin rate, with both individually predicting 43% of the observed variance in spin rate. Other kinematic parameters correlated with spin rate included: shoulder orientation at ball release (r = 0.462, p = 0.027), and pelvis-shoulder separation angle at front foot contact (r = 0.521, p = 0.011). The bowlers with the highest spin rates adopted a mid-way pelvis orientation angle, a larger pelvis-shoulder separation angle and a shoulder orientation short of side-on at front foot contact. The segments then rotated sequentially, starting with the pelvis and finishing with the pronation of the forearm. This knowledge can be translated to coaches to provide a better understanding of finger spin bowling technique.  相似文献   

11.
This study aimed to investigate whether high peak ground reaction forces and high average loading rates are necessary to bowl fast. Kinematic and kinetic bowling data were collected for 20 elite male fast bowlers. A moderate non-significant correlation was found between ball speed and peak vertical ground reaction force with faster bowlers tending to have lower peak vertical ground reaction force (r = ?0.364, P = 0.114). Faster ball speeds were correlated with both lower average vertical and lower average horizontal loading rates (r = ?0.452, P = 0.046 and r = ?0.484, P = 0.031, respectively). A larger horizontal (braking) impulse was associated with a faster ball speed (r = 0.574, P = 0.008) and a larger plant angle of the front leg (measured from the vertical) at front foot contact was associated with a larger horizontal impulse (r = 0.706, P = 0.001). These findings suggest that there does not necessarily need to be a trade-off between maximum ball release speed and the forces exerted on fast bowlers (peak ground reaction forces and average loading rates). Furthermore, it appears that one of the key determinants of ball speed is the horizontal impulse generated at the ground over the period from front foot contact until ball release.  相似文献   

12.
ABSTRACT

Cricket fast bowlers are at a high risk of injury occurrence, which has previously been shown to be correlated to bowling workloads. This study aimed to develop and test an algorithm that can automatically, reliably and accurately detect bowling deliveries. Inertial sensor data from a Catapult OptimEye S5 wearable device was collected from both national and international level fast bowlers (n = 35) in both training and matches, at various intensities. A machine-learning based approach was used to develop the algorithm. Outputs were compared with over 20,000 manually recorded events. A high Matthews correlation coefficient (r = 0.945) showed very good agreement between the automatically detected bowling deliveries and manually recorded ones. The algorithm was found to be both sensitive and specific in training (96.3%, 98.3%) and matches (99.6%, 96.9%), respectively. Rare falsely classified events were typically warm-up deliveries or throws preceded by a run. Inertial sensors data processed by a machine-learning based algorithm provide a valid tool to automatically detect bowling events, whilst also providing the opportunity to look at performance metrics associated with fast bowling. This offers the possibility to better monitor bowling workloads across a range of intensities to mitigate injury risk potential and maximise performance.  相似文献   

13.
Abstract

The inability of the between-bowlers methodology to control parameters external to technique could lead to erroneous significant and non-significant associations being reported between fast-bowling technique and ball release speed. Using Pearson's product – moment correlation, we first examined the effectiveness of a within-bowler methodology to identify associations between technique and ball release speed of an elite semi-open fast bowler over 20 deliveries. These results were compared with associations identified from a between-bowlers methodology in which 20 single-performance trials bowled by elite fast bowlers adopting a semi-open shoulder alignment were collated. Sufficient variation was observed in within-bowler ball release speed to allow f relationships to be identified between technique and ball release speed. Although greater variation in bowling technique parameters was observed in the between-bowlers methodology, no associations were identified between technique and ball release speed. Multiple stepwise regression analysis showed that 87.5% of the within-bowler variation in ball release speed can be attributed to run-up velocity, angular velocity of the bowling arm, vertical velocity of the non-bowling arm, and stride length. The within-bowler methodology provided significant detailed information about the individual bowler that the between-bowlers methodology overlooked, forming the basis of a performance enhancement programme. It is recommended that within-bowler methodology be used in future investigation of technique relationships.  相似文献   

14.
Cricket bowling is traditionally thought to be a rigid-arm motion, allowing no elbow straightening during the delivery phase. Conversely, research has shown that a perfectly rigid arm through delivery is practically unattainable, which has led to rule changes over the past years. The current rule requires a bowler not to increase the elbow angle by more than 15 degrees, thus requiring a measurement to confirm legality in "suspect" bowlers. The aims of this study were to evaluate whether the current rule is maintained over a range of bowlers and bowling styles, and to ascertain whether other kinematics measures may better differentiate between legal and suspect bowling actions. Eighty-three bowlers of varying pace were analysed using reflective markers and a high-speed (240 Hz) eight-camera motion analysis system in a laboratory. The change in elbow segment angle (minimum angle between the arm and forearm), the change in elbow extension angle with respect to the flexion-extension axis of a joint coordinate system, and the elbow extension angular velocity at ball release were measured. We found that bowlers generally bowled within a change in elbow extension angle of 15.5 degrees. However, this limit was unable to differentiate groups of bowlers from those who were suspected of throwing in the past. Improved differentiation was attained using the elbow extension angular velocity at ball release. The elbow extension angular velocity at ball release may be conceptually more valid than the elbow extension angle in determining which bowlers use the velocity-contributing mechanisms of a throw. Also, a high value of elbow extension angular velocity at ball release may be related to the visual impression of throwing. Therefore, it is recommended that researchers and cricket legislators examine the feasibility of specifying a limit to the elbow extension angular velocity at ball release to determine bowling legality.  相似文献   

15.
This paper presents a novel sensor technology to deduce the dynamics of a bowling ball. The sensor, a miniature wireless inertial measurement unit (IMU), incorporates MEMS accelerometers and angular rate gyros, a microcontroller, a low power RF transceiver, and a rechargeable battery. When embedded in a bowling ball, the IMU transmits the acceleration and angular velocity data that define the dynamics of the ball starting with the bowler’s delivery and its motion in the lane. Example results from professional bowlers illustrate how this technology can be used to assess bowler skill and ball performance. For instance, the IMU accurately measures the spin dynamics of the ball which are crucial to develop the ball “hook.” An analysis of ball dynamics in the lane is distilled to a measurable “hook potential” metric for further assessing bowler skill. Finally, the sensor presented herein is believed to be the world’s smallest, wireless IMU. This highly miniaturized and wireless design will enable parallel training systems for many sports, including basketball, baseball, crew, cricket, golf, fly fishing, soccer, softball, tennis, rowing, among others.  相似文献   

16.
Fast bowling in cricket is an activity that is well recognised as having high injury prevalence and there has been debate regarding the most effective fast bowling technique. The aim of this study was to determine whether two-year coaching interventions conducted in a group of elite young fast bowlers resulted in fast bowling technique alteration. Selected kinematics of the bowling action of 14 elite young fast bowlers were measured using an 18 camera Vicon Motion Analysis system before and after two-year coaching interventions that addressed specific elements of fast bowling technique. Mann-Whitney tests were used to determine whether any changes in kinematic variables occurred pre- and post-intervention between those who had the coaching interventions and those who didn't. The coaching interventions, when applied, resulted in a more side-on shoulder alignment at back foot contact (BFC) (p = 0.002) and decreased shoulder counter-rotation (p = 0.001) however, there was no difference in the degree of change in back and front knee flexion angles or lower trunk side-flexion. This study has clearly shown that specific aspects of fast bowling technique are changeable over a two-year period in elite level fast bowlers and this may be attributed to coaching intervention.  相似文献   

17.
The aim of this study was to compare the associations between lower limb biomechanics and ball release speed in 15 high-performance (HP) and 15 amateur fast bowlers. Kinematic and kinetic variables of the lower limbs collected in the laboratory environment with a 3D Vicon motion analysis system were compared between groups, as well as their associations with ball release speed. HP bowlers had a significantly higher run-up velocity at back foot impact but this difference became non-significant at ball release. Front knee kinematics were not statistically different, however effect sizes revealed medium-large differences with the HP group displaying a more extended knee joint at maximum flexion (d = 0.72) and ball release (d = 0.76). Only front hip positive power was significantly higher in the HP group and it was suggested that the probable cause was the HP bowlers having less knee flexion after front foot impact. From a joint power analysis, the extensor muscle groups of the hip and knee were shown to be important in developing ball release speed. This highlights the need for lower limb/core strength programmes to be multifaceted and focus on the muscles associated with both power and stability.  相似文献   

18.
Spin bowling plays a fundamental role within the game of cricket yet little is known about the initial ball kinematics in elite and pathway spin bowlers or their relationship to performance. Therefore, the purpose of this study was to record three-dimensional ball kinematics in a large and truly high level cohort of elite and pathway finger-spin (FS) and wrist-spin (WS) bowlers, identifying potential performance measures that can be subsequently used in future research. A 22-camera Vicon motion analysis system captured retro-reflective markers placed on the seam (static) and ball (dynamic) to quantify ball kinematics in 36 FS (12 elite and 24 pathway) and 20 WS (eight elite and 12 pathway) bowlers. Results indicated that FS bowlers delivered the ball with an increased axis of rotation elevation, while wrist-spin bowlers placed greater amounts of revolutions on the ball. It also highlighted that ball release (BR) velocity, revolutions and velocity/revolution index scores for both groups and seam stability for FS bowlers, and seam azimuth angle and spin axis elevation angle for WS bowlers, were discriminators of playing level. As such these variables could be used as indicators of performance (i.e. performance measures) in future research.  相似文献   

19.
The aim of this study was to assess the effect of pitch length (20.12 m [full length], 18 m and 16 m) on the fast bowling performance and technique of junior cricketers. Performance measures included ball release speed and accuracy, while technique variables evaluated were those shown to be related to the aetiology of lower back injury. Thirty-seven fast bowlers from the under-11 (n=14), under-13 (n=11) and under-15 (n=12) age groups were filmed bowling five deliveries at each of the above pitch lengths. Two synchronized NAC video cameras operating at 200 Hz permitted three-dimensional reconstruction of the hip and shoulder alignments, while a standard digital video camera operating at 50 Hz (positioned perpendicular to the bowling action) was used to measure front knee angle and ball release speed. Accuracy scores were taken from a zoned target at the batsman's stumps. A two-way analysis of variance with repeated measures (with age and pitch length as the between- and within-participant variables, respectively) was used to compare each age group at the 0.05 significance level. Results showed that accuracy improved in all age groups at shorter pitch lengths, although ball velocity remained constant throughout all trials. Shoulder counter-rotation increased significantly for the under-13 bowlers when bowling on the full-length pitch in comparison with the two shorter lengths. Counter-rotation also increased on the full-length pitch in the under-11 age group, although this increase was not significant. The under-15 bowlers' techniques did not change as pitch length increased. As under-11 and under-13 bowlers adopted a "safer" bowling action with superior accuracy on the 18?m compared with the full length pitch, it was concluded that these age groups should bowl on an 18?m pitch to reduce the likelihood of lower back injuries and improve accuracy.  相似文献   

20.
通过对2010年广州亚运会板球测试赛中国女队7名主力投手技术的高速影像解析,从球速、投球臂角速度、投球步落地位置和步长、落地时身体姿态、球出手瞬间关节角等方面分析比较中国女投手的各项投球技术。结果发现:不同类型投手之间技术特征差异性明显,快投手比旋转投手的落地到球出手时间短;好投手比差投手落地位置和空中姿态稳定性好。通过研究还发现部分投手存在球出手时膝关节弯曲、手臂弯曲等技术缺陷,以及前脚越过击球线等技术犯规错误,提醒在比赛中应引起注意。  相似文献   

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