René E.D. Ferdinands

Three-dimensional lumbar segment kinetics of fast bowling in cricket.

Cricket fast bowlers have a high incidence of serious lumbar injuries, such as lesions in the pars interarticularis. Kinematic studies have shown that bowling actions with large shoulder counter-rotation are associated with significantly higher incidences of lumbar injury. However, in bowling, there has been no calculation of the spinal loads, which are the causal mechanisms of such injuries. In this study, 21 fast bowlers (22.4+/-3.9 years) of premier grade level and above were tested using a three-dimensional (3D) motion analysis system. The mean ball release speed was 31.9+/-2.8 m s(-1) and ranged from 27.0 to 35.6 m s(-1). Kinematics and kinetics were calculated for lumbar spine lateral bending, rotation, and flexion during the delivery and power phases of bowling. Power calculations were used to define the actuation of lumbar spine motion as either active or controlled. The actuation of the lumbar spine was complex, involving multiple sequences of active and controlled motion. In addition, lumbar spine loads were largest during the power phase when the ground reaction forces were highest. In conclusion, the dynamic loads and the cyclical nature of their application when the spine is positioned near its end range of motion may be significant factors of injury to this region. In addition, the lumbar spine in bowling has to vigorously flex, laterally bend and rotate simultaneously in a complex interdependent sequence of actuation patterns. Therefore, any technical change to reduce injury susceptibility needs to consider the mechanics of whole body coordination and timing.

Throwing velocity and accuracy in elite and sub-elite cricket players: A descriptive study

Abstract Release velocity and accuracy are vital components of throwing performance. However, there is no published research on these parameters for throwing in cricket. In this study, we investigated the throwing performance of 110 cricket players from six different populations: elite senior males, elite under-19 junior males, elite under-17 junior males, elite senior females, elite under-19 junior females, and sub-elite senior males. Based on a specifically designed cricket throwing test, participants were assessed for (1) maximal throwing velocity and (2) throwing accuracy at maximal velocity and at three sub-maximal velocities. Elite senior males exhibited the highest peak and mean maximal throwing velocities (P≤0.001). Furthermore, the groups of males had significantly higher peak and mean maximal throwing velocities than the groups of females (P≤0.01). A speed–accuracy trade-off existed such that all groups demonstrated improved accuracy scores at velocities between 75% and 85% maximal throwing velocity compared with 50% maximal throwing velocity and 100% perceived maximal exertion. The results indicate that sex, training experience (years training), and training volume (training time per week) may contribute to throwing performance in cricket players. Further research should focus on understanding the mechanisms behind the observed differences between these groups. This is the first study to describe the inherent throwing profiles of different cricket playing populations. Potentially, we have identified stimulus material for future training developments.

Distribution of modern cricket bowling actions in New Zealand

Abstract The classification of bowling actions in cricket is particularly important from an injury perspective. Research has consistently shown that bowlers with a mixed-action technique have an elevated risk of sustaining serious lumbar injury. In this study, 34 New Zealand bowlers (mean age 22.2±0.9 years) of premier competition standard and above were assessed using a three-dimensional motion analysis system (240 Hz). Data were analysed using three previous classification systems before classifying bowlers into the side-on, semi-open, front-on, and mixed-action types based on a modified set of angle threshold criteria and a more intuitive angle convention system. The majority of bowlers in the sample (64.7%) used the mixed action with high levels of shoulder counter-rotation. The strongest predictors of shoulder counter-rotation were shoulder alignment angle and pelvic–shoulder separation angle. The current results suggest that a large proportion of fast bowlers may be at a higher risk of lumbar injury from the use of the mixed-action technique. We believe it may be advisable to recommend the semi-open action as an alternative to the front-on action. In addition, the adopted angle convention is more practical than the previous convention for bowling action classification.

The effect of a flexed elbow on bowling speed in cricket.

Abstract The laws of bowling in cricket state ‘a ball is fairly delivered in respect of the arm if, once the bowlers 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.

An evaluation of biomechanical measures of bowling action legality in cricket

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.

Centre of mass kinematics of fast bowling in cricket

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.

Indicators of throwing arm fatigue in elite adolescent male baseball players: a randomized crossover trial.

Abstract Freeston, J, Adams, R, Ferdinands, RED, and Rooney, K. Indicators of throwing arm fatigue in elite adolescent male baseball players: A randomized crossover trial. J Strength Cond Res 28(8): 2115–2120, 2014—Throwing carries an inherent risk of injury that worsens in the presence of arm fatigue. The purpose of this study was to identify markers that could facilitate the early detection of this type of fatigue, by comparing the response to bouts of throwing-specific and running-based exercise. Thirteen elite junior male baseball players were tested twice, 7 days apart with a randomized crossover design. They were assessed for shoulder proprioception, maximal throwing velocity, and throwing accuracy before and after a 10-minute bout of either throwing-specific (THROW) or general (RUN) exercise. Maximal throwing velocity was reduced similarly after both THROW and RUN bouts (−1.0 ± 0.4 vs. −0.6 ± 0.2 m·s−1, respectively; p ⩽ 0.05); however, accuracy was only reduced after THROW (7.6 ± 3.4 cm; p ⩽ 0.05). Arm soreness increased significantly more after THROW than RUN (3.5 ± 0.7 vs. 1.4 ± 0.5 km·h−1, respectively; p ⩽ 0.05). Shoulder proprioception did not change after either exercise bout. The results suggest that throwing velocity is an indicator of general fatigue, whereas throwing accuracy and arm soreness are markers of arm fatigue. Shoulder proprioception does not seem to be a sensitive marker of either type of fatigue. Throwing velocity should be monitored to gauge overall fatigue levels, whereas accuracy and arm soreness should be closely monitored to gauge arm fatigue and throwing-induced injury risk.

Kinematic and kinetic energy analysis of segmental sequencing in cricket fast bowling

Although there have been many studies to quantify the segmental sequencing in other sports, there has been little such research applied to cricket bowling. In this study, 34 fast bowlers (22.3 ± 3.7 years) of premier grade level and above were tested using 3D motion analysis, their balls speed ranging from 27.0 to 35.6 m s− 1. One-way repeated measures ANOVA was used to test for within-participant differences in segmental sequencing based on the timings of maximum segmental angular velocities and kinetic energies, the data showing that bowlers exhibited a general order of proximal-to-distal sequencing. Bivariate Pearsons product-movement correlation coefficients were calculated to assess the relationships between kinematic variables and ball release speed, yielding a set of variables for entry into a stepwise multiple regression model. The multiple regression model with the sequential timing variables of thoracic linear kinetic energy (KE), upper-arm circumduction velocity and forearm rotation KE, as well as the pelvic–shoulder separation acceleration accounted for 55% of the variability in ball speed (R 2 = 0.55, adjusted R 2 = 0.49, F(4, 29) = 8.86, p < 0.001). This study showed that both the magnitude and the timing of segmental activation are important to generate ball speed in fast bowling.

The kinematic differences between off-spin and leg-spin bowling in cricket

Abstract 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.

Three-dimensional linear and angular kinematics of a spinning cricket ball

The purpose of this study was to analyse the performance outcomes of spin bowlers by using a motion analysis procedure to measure the linear and angular kinematics of a spinning ball. A three-dimensional (3D) Cortex motion analysis system was used to track three markers strategically placed on the ball spinning in flight. Data were further processed using 3D vector kinematics to calculate the balls linear speed, spin rate and direction of the angular velocity vector. Thirty-four district-level spin bowlers, including both finger-spinners and wrist-spinners, were recruited to bowl 20 standard deliveries, and 5 deliveries of any variation in their repertoire. The results show that spin bowlers can produce various combinations of spin rate and angular velocity vector orientations to implement substantially different methods of utilising both swerve and turn off the pitch to deceive the batsman. In particular, it was found that wrist-spin bowlers could potentially swerve the ball either towards the left or right of the batsman. In addition, the balls angular velocity vector can be displayed during the live capture, which is able to demonstrate spin-bowling performance in the laboratory.