Bowling Arm Research Articles

Effect of Information Load and Time on Observational Learning

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.

The off-break and “doosra”: Kinematic variations of elite and sub-elite bowlers in creating ball spin in cricket bowling

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.

Musculoskeletal profile of the lumbar spine and hip regions in cricket fast bowlers

Objectives To determine the career history of low back pain (LBP) in current elite female cricket fast bowlers and then compare measures of lumbar spine and hip range of motion (ROM) and trunk extensor endurance between those bowlers with and without a history of LBP. Measures for the female bowlers were also compared to a small sample of male fast bowlers. Participants Twenty-six elite female fast bowlers and eight male fast bowlers of similar age and bowling experience. Main outcome measures The career history of LBP was determined by a self-administered questionnaire and by accessing medical records. Range of motion measures for the lumbar spine and hips were obtained using inclinometry or goniometry. Trunk extensor endurance was assessed using a modified Sorensen test. Results Fourteen female fast bowlers had a history of LBP. There was a significant difference in lumbar lateral flexion ROM to the bowling arm side between those female fast bowlers with and without a history of LBP ( p⩽0.05). The female fast bowlers had significantly more bilateral hip extension ROM ( p⩽0.05) compared to the male fast bowlers. Conclusions This information should be useful for practitioners involved in the conditioning and rehabilitation of cricketers. Future prospective studies should investigate potential predictors of LBP in female fast bowlers.

Use of field-based tests to identify risk factors for injury to fast bowlers in cricket

Objective:To identify risk factors for injury to cricket fast bowlers using field-based tests.Design:Prospective cohort study.Setting:High performance Australian cricket.Participants:Ninety-one male adolescent and adult fast bowlers (aged 12–33 years).Assessment of risk factors:A...

The associations between fast bowling technique and ball release speed: A pilot study of the within-bowler and between-bowler approaches

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.

A comparison of intra- and inter-limb relative motion information in modelling a novel motor skill

The importance of intra- and inter-limb relative motion in modelling a whole body coordination skill was examined. Participants were assigned to one of four groups: Full-Body point light model of a cricket bowler, INTRA-LIMB relative motion of the bowling arm, INTER-LIMB relative motions of the right and left wrists or NO-Relative motion, showing only the motions of the right wrist. During 60 acquisition trials, participants viewed the model five times before each 10-trial block. Retention was examined the following day. Although all groups improved on intra-limb coordination of the bowling arm, the INTRA-LIMB and FULL-BODY groups were more accurate than the INTER-LIMB group in acquisition, although these groups did not differ in retention. For inter-limb coordination, the three groups who received relative motion information performed more like the model than the NO-Relative motion group (even though the INTRA-LIMB group did not see the other limb). The amount of information within a display plays a constraining role on acquisition, perhaps more so than the type of information, such that the acquisition of coordination is more an emergent feature of observational learning, rather than a direct approximation of the model.

Cricket

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°, max = 22°, mean ± SD = 9 ± 5°), 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°). When assessed against an arbitrary threshold of 15° 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°) than the good length deliveries (9 ± 4.4°) and the full deliveries (8 ± 5.7°), 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.

Single Photon Emission Computerized Tomography and Reverse Gantry Computerized Tomography Findings in Patients With Back Pain Investigated for Spondylolysis

Athletes with low back pain may have sustained a bone stress injury in the lumbar neural arch, including spondylolysis. Single photon emission computerized tomography (SPECT) and reverse gantry computerized tomography (rg-CT) help localize bone stress response and spondylolyses. To describe the SPECT and rg-CT findings in those patients suspected of suffering from a spondylolysis. Large retrospective case series. Secondary and tertiary care center in England. A total of 213 patients presenting to the Spinal Unit and Sports Medicine Clinics between 1995 and 2000 with low back pain and subsequently investigated for spondylolysis by SPECT and rg-CT. An experienced consultant musculoskeletal radiologist reported the SPECT and rg-CT, and these results along with data from the patient's medical records were analyzed. Sites and sides of increased scintigraphic activity in the lumbar neural arch seen on SPECT and complete and incomplete spondylolyses were recorded. Single photon emission computerized tomography scan showed increased scintigraphic uptake in 145 patients, mostly (42.3%) at L5. Marked increase in scintigraphic uptake was noted on the left side of the neural arch in 31 patients and on the right in 17 (chi; P < 0.05). Spondylolysis was identified on rg-CT in 81 patients. Spondylolyses were bilateral on 44 occasions, but unilateral lesions occurred in the left pars 36 times and on the right 16 times (chi; P < 0.01) Spondylolyses were a frequent finding on rg-CT in young athletes with low back pain. The sports most commonly associated with this stress response in the pars interarticularis were cricket and soccer. The lower lumbar levels are more likely to show abnormalities on SPECT and computerized tomography. Among those investigated for spondylolysis, left-sided lower lumbar pain was more common than right, and a marked increase in scintigraphic uptake was noted on the left more often than the right. Although bilateral spondylolyses were common, left-sided spondylolyses were more common than right. The asymmetric repetitive movements of certain sports may be responsible. In particular, fast bowlers developed spondylolysis on the opposite side of the body to their bowling arm.

Shoulder injuries in provincial male fast bowlers - predisposing factors

Objectives. To investigate the relationship between shoulder flexibility and isokinetic strength as possible factors that may predispose provincial fast bowlers to shoulder injuries. Design. Twenty-one players, 12 of whom had no history of shoulder injuries and 9 of whom had experienced a shoulder injury to the bowling arm, were assessed for shoulder strength using a Cybex Norm isokinetic dynamometer. Absolute and relative peak torque measures were obtained at isokinetic speeds of 90°/s and 180°/s, with both concentric and eccentric contractions performed. Shoulder flexibility was tested using a Leighton Flexometer in both internal and external shoulder rotation. The players were classified into a front-on (N = 7), semi front-on (N = 7) or side-on (N = 7) bowling action from video footage recorded after a bowling trial in the nets. Results. Shoulder injuries were more common in fast bowlers with a front-on action (N = 5) than the bowlers with a side-on (N = 2) or semi front-on (N = 2) action. Sixteen of the 21 fast bowlers showed low stability ratios compared with gravity corrected functional ratios, indicating an imbalance and the presence of possible dysfunction. The injured group of fast bowlers showed higher concentric weight-normalised torque values for internal rotation at the higher velocity (180°/s) (65.20 ± 10.03 vs. 45.91 ± 10.26 Nm.kg-1 p &lt; 0.009: injured vs. uninjured), which would suggest greater instability when compared with the uninjured players. This imbalance could indicate the presence of a predisposition to impingement syndrome in the injured subjects. There was an increase in the external rotation ranges of movement for both groups, indicating a degree of hypermobility in both groups. The results indicate that the presence of possible dysfunction in the shoulder rotators, combined with a front-on bowling action and external rotation hypermobility, are possible predisposing factors for chronic shoulder injuries in cricket fast bowlers. South African Journal of Sports Medicine Vol.16(1) 2004: 25-28

Shoulder injuries in provincial male fast bowlers - predisposing factors

Objectives. To investigate the relationship between shoulder flexibility and isokinetic strength as possible factors that may predispose provincial fast bowlers to shoulder injuries. Design. Twenty-one players, 12 of whom had no history of shoulder injuries and 9 of whom had experienced a shoulder injury to the bowling arm, were assessed for shoulder strength using a Cybex Norm isokinetic dynamometer. Absolute and relative peak torque measures were obtained at isokinetic speeds of 90°/s and 180°/s, with both concentric and eccentric contractions performed. Shoulder flexibility was tested using a Leighton Flexometer in both internal and external shoulder rotation. The players were classified into a front-on (N = 7), semi front-on (N = 7) or side-on (N = 7) bowling action from video footage recorded after a bowling trial in the nets. Results. Shoulder injuries were more common in fast bowlers with a front-on action (N = 5) than the bowlers with a side-on (N = 2) or semi front-on (N = 2) action. Sixteen of the 21 fast bowlers showed low stability ratios compared with gravity corrected functional ratios, indicating an imbalance and the presence of possible dysfunction. The injured group of fast bowlers showed higher concentric weight-normalised torque values for internal rotation at the higher velocity (180°/s) (65.20 ± 10.03 vs. 45.91 ± 10.26 Nm.kg-1 p &lt; 0.009: injured vs. uninjured), which would suggest greater instability when compared with the uninjured players. This imbalance could indicate the presence of a predisposition to impingement syndrome in the injured subjects. There was an increase in the external rotation ranges of movement for both groups, indicating a degree of hypermobility in both groups. The results indicate that the presence of possible dysfunction in the shoulder rotators, combined with a front-on bowling action and external rotation hypermobility, are possible predisposing factors for chronic shoulder injuries in cricket fast bowlers. South African Journal of Sports Medicine Vol.16(1) 2004: 25-28

Comparing spondylolysis in cricketers and soccer players

Objective: To determine whether the location of spondylolysis in the lumbar spine of athletes differs with biomechanical factors. Methods: Single photon emission computerised tomography and reverse gantry computerised tomography were...

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.

Effects of propranolol inhalation on the diurnal increase in FEV1 and on propranolol airways responsiveness in atopic subjects with asthma.

Propranolol inhalation provocation tests are used to measure indirect airways responsiveness in the investigation of asthma. In this study the effects of repeated propranolol inhalation provocation tests within the same day on normal diurnal variation in the forced expiratory volume in one second (FEV1) and subsequent propranolol airways responsiveness were investigated. Fifteen atopic asthmatic subjects were challenged with doubling concentrations of propranolol at 08.00 and 16.00 hours on the same study day and at 16.00 hours on a control day to exclude changes related to normal diurnal variation. Mean (SD) baseline FEV1 at 16.00 hours on the study day was 3.38 (0.23) 1, significantly lower than the value at 16.00 hours on the control day of 3.70 (0.24) 1 (p = 0.001). No differences were found between the geometric mean provocative concentration of propranolol causing a 20% fall in FEV1 (PC20) measured on the study day (08.00 hours, 9.3 mg/ml; 16.00 hours, 11.3 mg/ml) and on the control day (16.00 hours 9.3 mg/ml). The results suggest that propranolol provocation at 08.00 hours has a long lasting effect on FEV1, thereby counteracting the normal diurnal increase in diameter of the airways. This makes propranolol challenge tests less suitable for studying indirect airways responsiveness in the course of one day. Because the FEV1 does not return to control values, it is not possible to determine whether tachyphylaxis to repeated propranolol challenge with a time interval of up to eight hours occurs.