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1.
Abstract

In the sport of cricket the objective of the “no-ball” law is to allow no performance advantage through elbow extension during ball delivery. However, recently it has been shown that even bowlers with actions that are considered within the law show some elbow extension. The objective of this study was to investigate: [1] the effect of elbow orientation during anatomical landmark digitisation and [2] the choice of upper arm tracking cluster on the measurement of elbow angles during cricket bowling.

We compared the mean elbow angles for four different elbow postures; with the joint flexed at approximately 130°, 90°, in full extension and with the elbow flexed with the humerus internally rotated, and two upper arm clusters in two different situations: [1] during a controlled movement of pure flexion-extension and [2] during cricket bowling. The digitised postures of the anatomical landmarks where the elbow was extended and at 90° of flexion were more repeatable than the other two postures. The recommendation of this study when analysing cricket bowling is to digitise the humeral epicondyles with the joint flexed at 90°, or in full extension, and to relate their positions to an upper arm cluster fixed close to the elbow.  相似文献   

2.
The elbow extension angle during bowling in cricket may be calculated from the positions of markers attached around the shoulder, elbow and wrist using an automated laboratory-based motion analysis system. The effects of two elbow-marker sets were compared. In the first, a pair of markers was placed medially and laterally close to the condyles while in the second a triad of markers was placed on the back of the upper arm close to the elbow. The root mean square (RMS) difference in elbow extension angle between the two methods at four key instants was 8° for 12 fast bowlers and 4° for 12 spin bowlers. When evaluated against video estimates of the elbow extension angle for the fast bowlers, the elbow extension angle calculated using the pair method had an RMS error of 2° while the triad method had an RMS error of 8°. The corresponding errors for the spin bowlers were 3° and 5°, respectively. It is thought that the greater errors associated with the triad is a consequence of soft tissue movement in this dynamic activity. This is consistent with the finding of greater error for the fast bowlers compared with the spin bowlers.  相似文献   

3.
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.
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   

5.
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   

6.
In cricket bowling, the reconstruction of elbow angle data is of utmost importance to the bowling versus throwing argument. This paper reviews system and modelling errors inherent in three-dimensional reconstruction processes with respect to the elbow extension tolerance set by the International Cricket Council. An understanding of these factors will enable more informed decisions about the choice of in-field versus laboratory testing in the calculation of elbow extension during bowling in cricket. Although there is a paucity of objective data related to in-field and laboratory testing, biomechanists must be guided by the greater accuracy of opto-reflective than video-based systems and so testing, at least for the present, should be conducted in a laboratory setting.  相似文献   

7.
In cricket bowling, the reconstruction of elbow angle data is of utmost importance to the bowling versus throwing argument. This paper reviews system and modelling errors inherent in three-dimensional reconstruction processes with respect to the elbow extension tolerance set by the International Cricket Council. An understanding of these factors will enable more informed decisions about the choice of in-field versus laboratory testing in the calculation of elbow extension during bowling in cricket. Although there is a paucity of objective data related to in-field and laboratory testing, biomechanists must be guided by the greater accuracy of opto-reflective than video-based systems and so testing, at least for the present, should be conducted in a laboratory setting.  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.
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   

10.
Abstract

The aim of this study was to examine the relationship between shoulder alignment and elbow angle during the delivery action of fast-medium bowlers. The elbow and upper trunk alignment were recorded for 13 high-performance bowlers (mean age 20 years) using a 12-camera Vicon motion analysis system operating at 250 Hz. The three highest velocity trials for “good” and “short” length deliveries were analysed. Results showed that bowlers with a more front-on shoulder alignment at back-foot impact and when the upper arm was horizontal to the ground experienced a significantly greater elbow flexion – extension range when compared with those who had a more side-on orientation at the same point in the delivery action. Bowlers with greater shoulder counter-rotation also recorded higher elbow flexion and subsequently extension during the period from upper arm horizontal to ball release. Shoulder alignment and elbow angles were similar for “short” and “good” length deliveries. It was concluded that bowlers with a more front-on shoulder orientation at back-foot impact demonstrated a higher elbow extension from upper arm horizontal to ball release and are therefore more likely to infringe International Cricket Council elbow tolerance levels, compared with those who adopt a more side-on shoulder orientation at back-foot impact.  相似文献   

11.
The aim of this study was to examine the relationship between shoulder alignment and elbow angle during the delivery action of fast-medium bowlers. The elbow and upper trunk alignment were recorded for 13 high-performance bowlers (mean age 20 years) using a 12-camera Vicon motion analysis system operating at 250 Hz. The three highest velocity trials for "good" and "short" length deliveries were analysed. Results showed that bowlers with a more front-on shoulder alignment at back-foot impact and when the upper arm was horizontal to the ground experienced a significantly greater elbow flexion--extension range when compared with those who had a more side-on orientation at the same point in the delivery action. Bowlers with greater shoulder counter-rotation also recorded higher elbow flexion and subsequently extension during the period from upper arm horizontal to ball release. Shoulder alignment and elbow angles were similar for "short" and "good" length deliveries. It was concluded that bowlers with a more front-on shoulder orientation at back-foot impact demonstrated a higher elbow extension from upper arm horizontal to ball release and are therefore more likely to infringe International Cricket Council elbow tolerance levels, compared with those who adopt a more side-on shoulder orientation at back-foot impact.  相似文献   

12.
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   

13.
This study investigated the bowling arm kinematics of 21 elite fast bowlers (mean +/- SD; age = 27.8 +/- 3.9 years) while performing in test, tour and one day international matches. Thirty-one of the 34 deliveries analysed exhibited straightening at the elbow joint (straightening min = 3 degrees, max = 22 degrees, mean +/- SD = 9 +/- 5 degrees), which by strict definition in the 2000 laws of cricket made them illegal. Five deliveries from three bowlers exhibited hyperextension of the bowling elbow (19 +/- 5 degrees). When assessed against an arbitrary threshold of 15 degrees for elbow straightening, ball speeds for deliveries above this threshold (39.5 +/- 2.0 m/s) were significantly faster (effect size = 1.4; p = 0.006) than deliveries below it (37.1 +/- 1.4 m/s). When grouped by delivery length, the bouncers and short deliveries recorded more elbow straightening (12 +/- 6.6 degrees) than the good length deliveries (9 +/- 4.4 degrees) and the full deliveries (8 +/- 5.7 degrees), although these were not statistically significant differences. The results of this study support the implementation of a tolerance threshold for assessing the legality of fast bowling actions. Further research is recommended into in-match kinematic modelling, laboratory based assessments of illegal bowling actions, perceptual aspects of bowling actions and remedial methods to reduce elbow straightening in bowling actions.  相似文献   

14.
The purpose of this study was to measure the contributions of the motions of body segments and joints to racquet head speed during the tennis serve. Nine experienced male players were studied using three-dimensional film analysis. Upper arm twist orientations were calculated with two alternative methods using joint centres and skin-attached markers. The results showed that skin-attached markers could not be used to calculate accurate upper arm twist orientations due to skin movement, and that the use of joint centres produced errors of more than 20 degrees in the upper arm twist orientation when the computed elbow flexion/extension angle exceeded 135 degrees in the final 0.03 s before impact. When there were large errors in the upper arm twist orientation, it was impossible to obtain accurate data for shoulder or elbow joint rotations about any axis. Considering only the contributors that could be measured within our standards of acceptable error, the approximate sequential order of main contributors to racquet speed between maximum knee flexion and impact was: shoulder external rotation, wrist extension, twist rotation of the lower trunk, twist rotation of the upper trunk relative to the lower trunk, shoulder abduction, elbow extension, ulnar deviation rotation, a second twist rotation of the upper trunk relative to the lower trunk, and wrist flexion. The elbow extension and wrist flexion contributions were especially large. Forearm pronation made a brief negative contribution. Computed contributions of shoulder internal rotation, elbow extension and forearm pronation within the final 0.03 s before impact were questionable due to the large degree of elbow extension. Near impact, the combined contribution of shoulder flexion/extension and abduction/adduction rotations to racquet speed was negligible.  相似文献   

15.
This study investigates how elbow hyperextension affects ball release speed in fast bowling. A two-segment planar computer simulation model comprising an upper arm and forearm + hand was customised to an elite fast bowler. A constant torque was applied at the shoulder and elbow hyperextension was represented using a damped linear torsional spring at the elbow. The magnitude of the constant shoulder torque and the torsional spring parameters were determined by concurrently matching three performances. Close agreement was found between the simulations and the performances with an average difference of 3.8%. The simulation model with these parameter values was then evaluated using one additional performance. Optimising ball speed by varying the torsional spring parameters found that elbow hyperextension increased ball release speed. Perturbing the elbow torsional spring stiffness indicated that the increase in ball release speed was governed by the magnitude of peak elbow hyperextension and the amount that the elbow recoils back towards a straight arm after reaching peak elbow hyperextension. This finding provides a clear understanding that a bowler who hyperextends at the elbow and recoils optimally will have an increase in ball speed compared to a similar bowler who cannot hyperextend. A fast bowler with 20° of elbow hyperextension and an optimal level of recoil will have increased ball speeds of around 5% over a bowler without hyperextension.  相似文献   

16.
Some studies have reported that overarm baseball pitching shows a proximal to distal sequential joint motion including a rapid extension of the elbow. It has been suggested that the rapid elbow extension just before ball release is not due to the action of the elbow extensor muscles, but the underlying mechanisms are not so clear. The purpose of this study was to determine the contributions of each joint muscular- and motion-dependent torques, including the upper trunk and throwing arm joints to generate the rapid elbow extension during baseball pitching. The right handed throwing motions of three baseball pitchers were recorded using five high-speed video cameras and the positional data were calculated using the direct linear transformation method. A throwing arm dynamic model of the upper trunk and throwing arm joints was then used, including 10 degrees of freedom, to calculate the throwing arm joint muscular-, throwing arm and upper trunk joint motion-, gravity-, and external force-dependent components that contribute to the maximum elbow extension angular velocity. The results showed that the rapid elbow extension was primarily due to the upper trunk counterclockwise rotation and shoulder horizontal adduction angular velocity-dependent torques. This study implied that the trunk counterclockwise rotators and shoulder horizontal adductors generate positive torques to maintain the angular velocities of the upper trunk counterclockwise rotation and shoulder horizontal adduction may play a key role in producing the rapid elbow extension.  相似文献   

17.
Lower back injuries, specifically lumbar stress fractures, account for the most lost playing time in professional cricket. The aims of this study were to quantify the proportion of lower trunk motion used during the delivery stride of fast bowling and to examine the relationship between the current fast bowling action classification system and potentially injurious kinematics of the lower trunk. Three-dimensional kinematic data were collected from 50 male professional fast bowlers during a standing active range of motion trial and three fast bowling trials. A high percentage of the fast bowlers used a mixed bowling action attributable to having shoulder counter-rotation greater than 30 degrees. The greatest proportion of lower trunk extension (26%), contralateral side-flexion (129%), and ipsilateral rotation (79%) was used during the front foot contact phase of the fast bowling delivery stride. There was no significant difference in the proportions of available lower trunk extension, contralateral side-flexion, and ipsilateral rotation range of motion used during fast bowling by mixed and non-mixed action bowlers. Motion of the lower trunk, particularly side-flexion, during front foot contact, in addition to variables previously known to be related to back injury (e.g. shoulder counter-rotation), should be examined in future cross-sectional and prospective studies examining the fast bowling action and low back injury.  相似文献   

18.
Abstract

Lower back injuries, specifically lumbar stress fractures, account for the most lost playing time in professional cricket. The aims of this study were to quantify the proportion of lower trunk motion used during the delivery stride of fast bowling and to examine the relationship between the current fast bowling action classification system and potentially injurious kinematics of the lower trunk. Three-dimensional kinematic data were collected from 50 male professional fast bowlers during a standing active range of motion trial and three fast bowling trials. A high percentage of the fast bowlers used a mixed bowling action attributable to having shoulder counter-rotation greater than 30°. The greatest proportion of lower trunk extension (26%), contralateral side-flexion (129%), and ipsilateral rotation (79%) was used during the front foot contact phase of the fast bowling delivery stride. There was no significant difference in the proportions of available lower trunk extension, contralateral side-flexion, and ipsilateral rotation range of motion used during fast bowling by mixed and non-mixed action bowlers. Motion of the lower trunk, particularly side-flexion, during front foot contact, in addition to variables previously known to be related to back injury (e.g. shoulder counter-rotation), should be examined in future cross-sectional and prospective studies examining the fast bowling action and low back injury.  相似文献   

19.
We show how biomechanics can be used to accurately assess spin-bowling techniques (offspin, legspin and topspin) in cricket, under controlled conditions, when the player is suspected of throwing. A 50 Hz six-camera Vicon Motion Analysis system was used to record the movements of markers strategically placed on the upper limb during each of the above bowling actions. A kinematic model of the upper limb, created using Vicon BodyBuilder software, enabled the movements of the upper arm and forearm to be described during each delivery. Selected physical characteristics of the upper limb were also measured. The present 'no ball' law in cricket with reference to throwing states that 'the arm should not be straightened in the part of the delivery that immediately precedes ball release'. The bowler, Mutiah Muralitharan, was shown to maintain a relatively constant elbow angle in the 0.06 s before ball release. Furthermore, this angle changed little from the time that the upper arm was angled vertically downward until ball release during the three spin-bowling actions.  相似文献   

20.
We examined whether altering the amount of and moment when visual information is presented affected observational learning for participants practicing a bowling skill. On Day 1, four groups practiced a cricket bowling action. Three groups viewed a full-body point-light model, the model's bowling arm, or between-limb coordination of the model's left and right wrists only. Following retention tests on Day 2, all participants practiced after viewing a full-body display. Retention was again tested on Day 3. Bowling accuracy improved in all four practice groups. Kinematics of the bowling arm became more like the model for the full-body and intralimb groups only. All groups improved on measures of interlimb coordination. Visual search data indicated that participants mainly focused their gaze on the model's bowling arm. These data lead to the suggestion that viewing “end-effector” information (i.e., information pertaining to the bowling arm) is an important perceptual constraint early in observational learning. Implicit manipulations designed to increase attention to other sources of information did not facilitate the learning process.  相似文献   

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