The association between lower limb biomechanics and ball release speed in cricket fast bowlers: a comparison of high-performance and amateur competitors

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.     

The relationship between bowling action classification and three-dimensional lower trunk motion in fast bowlers in cricket

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.     

The relationship between bowling action classification and three-dimensional lower trunk motion in fast bowlers in cricket

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.     

The effect of elbow hyperextension on ball speed in cricket fast bowling

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.     

Auto detecting deliveries in elite cricket fast bowlers using microsensors and machine learning

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.     

Peak outward acceleration and ball release in cricket

The purpose of this study was to investigate the utility of peak outward acceleration (POA) measured from an inertial sensor worn at the wrist as an indicator of the critical end point of the bowling action – ball release, a critical element when assessing illegal actions. Twenty-one finger-spin and fast bowlers from nine countries were recruited from the ICC under-19 Cricket World Cup to take part in this research. Bowlers delivered a cross section of their standard deliveries while wearing an inertial sensor placed on their wrists. Ball release was determined by a validated motional analysis ball release (MABR) protocol and compared to the simultaneously collected POA. POA was shown to be highly correlated with MABR (R² = 0.98) and a Bland–Altman plot indicated that all 148 trials were within the 3.42 frame (0.014 s) limits of agreement. POA when measured by an inertial sensor worn on the wrist during bowling had a close relationship with an established method of identifying ball release in a biomechanical laboratory regardless of bowler and delivery type. Further, accuracy can be achieved with the adoption of a simple regression equation applied to the POA and as such is a valid measure of ball release in cricket bowlers.     

Contributions of joint rotations to ball release speed during cricket bowling: a three-dimensional kinematic analysis

The purpose of this study was to discover the contributions of individual upper body segmental rotations to ball release speed for cricket bowling and determine whether attempting to forcefully flex the lower trunk leads to an increase in ball release speed and bowling accuracy. Three dimensional kinematic data of eight male fast bowlers were recorded by a Vicon motion capture system under three cricket bowling conditions: (1) participants bowled at their stock delivery speeds (sub-max condition), (2) participants bowled at their absolute maximal speeds (max condition), and (3) participants bowled at their absolute maximal speeds but forced to flex the lower trunk (max-trunk condition). The accuracy of each delivery was also measured. The results showed that the average ball release speeds for the max-trunk condition were faster than the other two conditions. A general pattern of proximal to distal sequencing was observed for all three conditions. There was a slight decrement in accuracy seen in the max-trunk condition with respect to the other two conditions. For all three conditions, the upper arm rotation made the largest contribution, followed in turn by torso and thorax rotation, pelvis rotation, linear velocity of pelvis, and forearm and hand rotation.     

Back injuries and the fast bowler in cricket

Here, I review research that has investigated the aetiology of injuries experienced by adolescent and adult fast bowlers. Mechanical factors play an important role in the aetiology of degenerative processes and injuries to the lumbar spine. This is particularly so in fast bowling, where a player must absorb vertical and horizontal components of the ground reaction force that are approximately five and two times body weight at front-foot and rear-foot impact, respectively. Attenuated forces are transmitted to the spine through the lower limb, while additional foces at the lumbo-sacral junction are caused by trunk hyperextension, lateral flexion and twisting during the delivery stride. Fast bowlers are classified as side-on, front-on or mixed. The mixed action is categorized by the lower body configuration of the front-on action and the upper body configuration of the side-on technique. This upper body configuration is produced by counter-rotation away from the batsman in the transverse plane about the longitudinal axis of the body of a line through the two shoulders. Counter-rotations of 12–40° during a delivery stride have predicted an increased incidence of lumbar spondylolysis, disc abnormality and muscle injury in fast bowlers. During the delivery stride, the mixed bowling action also shows: more lateral flexion and hyperextension of the lumbar spine at front-foot impact, and a greater range of motion of the trunk over the delivery stride when compared with the side-on and front-on techniques. The pars interarticularis of each vertebra is vulnerable to injury if repetitive flexion, rotation and hyperextension are present in the activity. Fast bowlers should reduce shoulder counter-rotation during the delivery stride to reduce the incidence of back injuries. When a player is required to bowl for extended periods irrespective of technique, overuse is also related to an increased incidence of back injuries and must be avoided.     

Back injuries and the fast bowler in cricket

Here, I review research that has investigated the aetiology of injuries experienced by adolescent and adult fast bowlers. Mechanical factors play an important role in the aetiology of degenerative processes and injuries to the lumbar spine. This is particularly so in fast bowling, where a player must absorb vertical and horizontal components of the ground reaction force that are approximately five and two times body weight at front-foot and rear-foot impact, respectively. Attenuated forces are transmitted to the spine through the lower limb, while additional forces at the lumbo-sacral junction are caused by trunk hyperextension, lateral flexion and twisting during the delivery stride. Fast bowlers are classified as side-on, front-on or mixed. The mixed action is categorized by the lower body configuration of the front-on action and the upper body configuration of the side-on technique. This upper body configuration is produced by counter-rotation away from the batsman in the transverse plane about the longitudinal axis of the body of a line through the two shoulders. Counter-rotations of 12-40 degrees during a delivery stride have predicted an increased incidence of lumbar spondylolysis, disc abnormality and muscle injury in fast bowlers. During the delivery stride, the mixed bowling action also shows: more lateral flexion and hyperextension of the lumbar spine at front-foot impact, and a greater range of motion of the trunk over the delivery stride when compared with the side-on and front-on techniques. The pars interarticularis of each vertebra is vulnerable to injury if repetitive flexion, rotation and hyperextension are present in the activity. Fast bowlers should reduce shoulder counter-rotation during the delivery stride to reduce the incidence of back injuries. When a player is required to bowl for extended periods irrespective of technique, overuse is also related to an increased incidence of back injuries and must be avoided.     

Total,regional and unilateral body composition of professional English first-class cricket fast bowlers

There have been few reports of advanced body composition profiles of elite fast bowlers in the sport of cricket. Therefore, the aim of the current study was to determine total, regional and unilateral body composition characteristics of elite English first-class cricket fast bowlers in comparison with matched controls, using dual-energy X-ray absorptiometry (DXA). Twelve male fast bowlers and 12 age-matched, non-athletic controls received one total-body DXA scan. Anthropometric data were obtained as well as left and right regional (arms, legs and trunk) fat mass, lean mass and bone mineral content. Fast bowlers were significantly taller and heavier than controls (P < 0.05). Relative to body mass, fast bowlers possessed greater lean mass in the trunk (80.9 ± 3.7 vs. 76.7 ± 5.9%; P = 0.047) and bone mineral content in the trunk (2.9 ± 0.3 vs. 2.6 ± 0.3%; P = 0.049) and legs (5.4 ± 0.5 vs. 4.6 ± 0.6%; P = 0.003). In the arm region, fast bowlers demonstrated significantly greater unilateral differences in bone mineral content (10.6 ± 6.6 vs. 4.5 ± 3.9%; P = 0.012). This study provides specific body composition values for elite-level fast bowlers and highlights the potential for muscle and bone imbalances that may be useful for conditioning professionals. Our findings also suggest beneficial adaptations in body composition and bone mass in fast bowlers compared with their non-athletic counterparts.     

Increased delivery stride length places greater loads on the ankle joint in elite male cricket fast bowlers

Abstract

The purpose of this study was to investigate the effect stride length has on ankle biomechanics of the leading leg with reference to the potential risk of injury in cricket fast bowlers. Ankle joint kinematic and kinetic data were collected from 51 male fast bowlers during the stance phase of the final delivery stride. The bowling cohort comprised national under-19, first class and international-level athletes. Bowlers were placed into either Short, Average or Long groups based on final stride length, allowing statistical differences to be measured. A multivariate analysis of variance with a Bonferroni post-hoc correction (α = 0.05) revealed significant differences between peak plantarflexion angles (Short-Long P = 0.005, Average and Long P = 0.04) and negative joint work (Average-Long P = 0.026). This study highlighted that during fast bowling the ankle joint of the leading leg experiences high forces under wide ranges of movement. As stride length increases, greater amounts of negative work and plantarflexion are experienced. These increases place greater loads on the ankle joint and move the foot into positions that make it more susceptible to injuries such as posterior impingement syndrome.     

The relationships between impact location and post-impact ball speed,bat torsion,and ball direction in cricket batting

Three-dimensional kinematic data of bat and ball were recorded for 239 individual shots performed by twenty batsmen ranging from club to international standard. The impact location of the ball on the bat face was determined and assessed against the resultant instantaneous post-impact ball speed and measures of post-impact bat torsion and ball direction. Significant negative linear relationships were found between post-impact ball speed and the absolute distance of impact from the midline medio-laterally and sweetspot longitudinally. Significant cubic relationships were found between the distance of impact from the midline of the bat medio-laterally and both a measure of bat torsion and the post-impact ball direction. A “sweet region” on the bat face was identified whereby impacts within 2 cm of the sweetspot in the medio-lateral direction, and 4.5 cm in the longitudinal direction, caused reductions in ball speed of less than 6% from the optimal value, and deviations in ball direction of less than 10° from the intended target. This study provides a greater understanding of the margin for error afforded to batsmen, allowing researchers to assess shot success in more detail, and highlights the importance of players generating consistently central impact locations when hitting for optimal performance.     

The effect of altered pitch length on performance and technique in junior fast bowlers

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.     

The influence of elbow joint kinematics on wrist speed in cricket fast bowling

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.     

The relationship between shoulder alignment and elbow joint angle in cricket fast-medium bowlers

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.     

The relationship between shoulder alignment and elbow joint angle in cricket fast-medium bowlers

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.     

Psychomotor speed is related to perceived performance in rowers

Abstract

The goal of the present study was to determine if psychomotor speed is related to perceived performance. It was hypothesized that lower perceived performance was related to longer reaction times. A total of 85 measurements were taken in 26 varsity rowers (mean age 21.3 years, s=1.6) on five occasions over the course of the season. Perceived performance was measured with the “Reduced Sense of Accomplishment” scale of the Athlete Burnout Questionnaire. Reaction times were measured with the finger pre-cueing task and with the action and reaction modes of the determination test. The complex structured data were analysed with multi-level modelling. Random intercept linear models showed that perceived performance was not related to reaction times on the finger pre-cueing task. Perceived performance significantly predicted reaction times on the action and reaction modes of the determination test. In rowers who were not selected for the team after completing two measurement sessions, this relationship did not exist in the action mode; deselection was a moderator. Thus, a significant relationship between reaction times on the determination test and perceived performance was observed. It was concluded that the determination test could be a useful tool to monitor rowers’ responses to training, although several issues should be resolved before it can be used in practice.     

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

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.     

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.     

Timing of ball release in overarm throws affects ball speed in unskilled but not skilled individuals

We tested the hypothesis that variability in the timing of ball release in overarm throws affects ball speed. Nine unskilled and six skilled throwers made 30 throws fast and accurately from a sitting and standing position. Angular positions of finger and arm segments were recorded with search-coils at 1000 Hz; ball speed was measured with a radar gun. The time of ball release from the fingertips was measured with respect to seven arm kinematic reference points. Mean timing windows for ball release were 28 ms for unskilled throwers and 7 ms for skilled throwers. Mixed-model analyses of variance showed that a there was a statistically significant relationship between ball speed and the timing of ball release in unskilled throwers, but not in skilled throwers. This was presumably due to the difference in variability of the timing of ball release between the two groups. In contrast, skilled throwers showed a relationship between ball speed and peak forearm angular velocity (one measure of arm speed). We conclude that although variability in the timing of ball release can affect ball speed, this is only a major factor in unskilled throwers. When skilled throwers throw fast, variability in ball speed is due to variability in arm speed.