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

On Learning to Anticipate in Youth Sport

Elite sport offers a suitable setting to understand the ability to anticipate future events-a phenomenon that is central to animal life. Critically, however, whilst anticipation in sport has been studied for several decades, there have been few attempts to understand its development throughout childhood and adolescence. Additionally, whilst it is widely acknowledged that the need to anticipate emerges from temporal pressure, there has been no effort to understand the nonlinear effect that temporal demands have on the development of anticipatory skill. This is important as its consequences have different implications for sports authorities compared to an individual player. To bridge the gap in our understanding, this article draws attention to the mathematical concepts of concavity and convexity to explain the nonlinear relationship between temporal demands and the development of anticipatory skill. This viewpoint has implications for the design of junior sport, including the modification of rules, which has gained worldwide interest in recent years.

Scaling junior sport competition: A body-scaling approach?

The design of the junior sport competition environment plays a critical role in attracting and retaining children as life-long participants. Critically, however, the guidelines governing the design of junior sport are rarely scrutinized. With this in mind, our aim is to offer sports authorities a method to systematically assess the suitability of guidelines. The most popular junior ball sport competitions in Australia were assessed in relation to the scaling of task constraints and compared to children's corresponding physical maturation and/or performance measures. This assessment enabled the calculation of pi ratios, which were then used to categorise constraints as either (1) undersized, (2) appropriately sized or (3) oversized. Results revealed that most sports' ask children to play in oversized conditions, particularly in the under 9 to under 12 age groups and in boys' competitions. The task constraints that had the highest percentage of pi ratios appropriately sized were match duration and goal size. Comparatively, ball size and field length had the highest percentage of pi ratios classified as oversized. We contend that the systematic approach applied in this article should be used by sports authorities to understand the extent of scaling constraints in junior sport.

The association of stride length to ball velocity and elbow varus torque in professional pitchers

Professional basebal pitchers (n =315) were divided into quartiles based on increasing stride length and random intercept linear mixed-effect models were used to correlate stride length with ball velocity, pelvis and trunk rotation at foot contact, and throwing arm kinetics. Average stride length among all pitchers was 78.3±5.3%body height (%BH). For every 10% increase in stride length, ball velocity increased by 0.9 m/s (B =0.089, β =0.25, p <0.001) and trunk rotation initiation occurred 4.23 ms earlier (B =-0.42, β =-0.14, p <0.001). When divided into quartiles pelvis rotation was less towards home plate in Q1 compared to Q3 and Q4 (70.0±10.7° vs. 60.9±8.9° and 58.6±9.1°, p <0.001). No significant differences in shoulder internal rotation torque (p =0.173) or elbow varus torque (p =0.072) were noted between quartiles. Professional baseball pitchers who reached stride lengths of 80%BH or greater achieved faster ball velocity without an increase in elbow varus torque. This may, be a byproduct of rotating the pelvis for a greater proportion of the pitching motion and thereby more effectively utilising the lower extremities in the kinetic chain. Encouraging players to achieve this threshold of stride length may enhance ball velocity outcomes.

Scaling the cricket pitch to fit junior players

Studies in several sports have shown the benefits of adapting the playing environment to fit junior players. Frequently the changes are pragmatic choices based on space constraints or existing line markings, or the result of simple scaling based on stature. In this study, a method of scaling the cricket pitch length is presented which is based on the age-specific size and performance of the bowlers and batters. The objective was a pitch length which enabled young bowlers to bowl good length deliveries while releasing the ball at a more downward angle, similar to elite bowlers. The steeper release angle has the benefit of reducing the sensitivity of the ball flight distance to the variability of ball release. Based on data from county standard under-10 and under-11 players a pitch length of 16.22 yards (14.83 m) was calculated, 19% shorter than previously recommended for under-11s in England. A shorter pitch also increases the temporal challenge for batters, encouraging a wider variety of shots and improved anticipation skills. Pitch lengths scaled in this way to fit the players' abilities as they develop will enable a more consistent ball release by bowlers and more consistent temporal demand for batters.

Modifying bowling kinematics in cricket pace bowlers with exercise-based injury prevention: A cluster-randomised controlled trial

OBJECTIVES

Undesirable bowling kinematics can increase the risk of low back injury. This study investigated if an exercise-based injury prevention program (IPP) could modify bowling kinematics in community-level adolescent pace bowlers.

DESIGN

Cluster-randomised controlled trial.

METHODS

Pace bowlers from eight cricket organisations were cluster-randomised into an intervention or control group. At baseline and follow-up sessions biomechanical bowling data were collected. Between sessions, the intervention group completed an eight-week IPP while the control continued their normal cricket activity. Treatment effects (95% CI) were estimated with linear mixed models.

RESULTS

There were significant treatment effects favouring the intervention group for shoulder counter-rotation (-3.8°; -7.2° to -0.3°) and lateral trunk flexion relative to the pelvis (-2.2°; -4.0° to -0.5°). Shoulder counter-rotation also increased in the control group by 2.2° (Cohen's d=0.22). There were no effects of the intervention on: lateral trunk flexion at front foot contact (FFC) (1.2°; -2.5° to 4.8°), lateral trunk flexion at ball release (BR) (-0.5°; -3.0° to 2.0°), pelvis rotation at FFC (0.9°; -4.0° to 2.2°), pelvis rotation at BR (-1.1°; -5.7° to 3.6°), front hip angle at FFC (1.6°; -3.6° to 6.7°), front hip angle at BR (-1.6°; -5.0° to 1.9°), front knee angle at FFC (-1.1°; -4.5° to 2.3°), front knee angle at BR (1.7°; -5.6° to 9.1°), or ball velocity (1.1kmh^-1; -7.5kmh^-1 to 9.7kmh^-1).

CONCLUSIONS

The IPP maintained shoulder counter-rotation and lateral trunk flexion relative to the pelvis in the intervention group and this could attenuate injury risk. No treatment effects were observed for lower-limb kinematics.

The effect of equipment modification on the performance of novice junior cricket batters

Equipment scaling has yielded better performance in children in comparison to using adult equipment. To better inform applied practice in junior sport, an investigation of additional equipment modifications designed to further simplify the task is required. This study, therefore, aims to determine the effect of increasing surface area of cricket equipment (bats and balls) on batting performance and technique. Forty-three children (M _age = 5.2, SD = 0.8 years) completed a cricket batting task in which they aimed to hit the ball through a target zone while using either regular-scaled, or modified bat and ball with an increased surface area. The number of bat-ball contacts was significantly higher when using the modified (M = 13.81, SE = 0.42) compared to the regular-scaled ball (M = 10.65, SE = 0.49). Batting performance measured as shots played through target areas was also significantly higher when using the modified (M = 31.78, SE = 1.97) than the regular-scaled ball (M = 28.85, SE = 2.27). More desirable technique was also observed when using the modified compared to the regular bat. Findings suggest that further modifications to regular-scaled equipment can enhance skill production.

Scaling sports equipment for children promotes functional movement variability

Scaling sports equipment to match the physical development of children allows motor skills to be performed with greater success and with more desirable movement patterns. It is unknown, however, how scaled equipment affects movement variability – a key factor associated with coordination. Our aim was to identify whether scaled sports equipment facilitates coordination and functional movement variability in children when performing a hitting for accuracy task in tennis. Twenty-five children were asked to execute a forehand stroke with the aim of hitting the ball to a target located 10 metres away. Participants performed the task in two conditions – a scaled equipment condition and a full-sized equipment condition. Scaled equipment led to superior hitting accuracy and greater temporal stability of the swing compared to full-sized equipment. Scaled equipment also afforded the emergence of a functional coupling between upper arm and forearm movement variability which helped regulate the distance between the shoulder and the racket. Comparatively there was a lack of coupling when full-sized equipment was used. Hence, scaled equipment promoted functional movement variability, whereas full-sized equipment resulted in the freezing of mechanical degrees of freedom. This suggests that children’s skill acquisition could be hindered and potentially regress when using inappropriately sized equipment.

Designing Junior Sport to Maximize Potential: The Knowns, Unknowns, and Paradoxes of Scaling Sport

In this mini-review, we draw attention to an important yet relatively untapped topic in the developmental pathway - the design of junior sport so that it appropriately matches the functional capacities of children. Junior sport is a regular weekend activity for many children across the world, yet many will be required to prematurely play on a field or with equipment that is designed for adults. Herein lies an opportunity for sport administrators to nurture children's development in sport by appropriately manipulating the rules and dimensions of the game. The aim of this mini-review is to (1) draw attention to the value of scaling junior sport, (2) highlight paradoxes within the current scaling sport literature, and (3) emphasize a way forward for junior sport research. If we are genuine in our endeavor to tailor sports experiences for children, more sophisticated approaches to scaling those experiences are a must.

Effect of Modification Rules in Competition on Technical-Tactical Action in Young Tennis Players (Under-10)

Adapting competitions to young players' characteristics is an important pillar in the optimal teaching-learning process. The objective of the present study is to analyze the effect of modifying net height (from 0.91 to 0.80 m) and court dimensions (from 23.77 × 8.23 m to 18 × 8.23 m) for under-10 (U-10) tennis players on the following: (a) kinds of technical and tactical basic, situational, and special strokes; (b) tennis players' hitting area; (c) landing location of the serve; (d) ball landing location after the serve; (d) stroke effectiveness; and (e) rally length. The study design was quasi-experimental in nature, observing the fluctuation/change in technical-tactical variables of the tennis players when playing a "Tennis 10s Green Competition" (GC) with the current federative rules and a redesigned competition "Modified Competition" (MC) including altered net height and court dimensions based on small-sided games (SSGs) and equipment scaling. Twenty U-10 tennis players were studied (age of players = 9.46 ± 0.66 years, average weekly training in tennis = 2.90 ± 1.07 h, years of experience = 3.65 ± 1.53 years). The results showed that in MC, there was a greater technical-tactical variability compared with the GC in terms of the following: (a) greater service effectiveness; (b) more situational and special strokes; and (c) a more equitable change in the distribution of hitting and ball landing locations. The values of MC showed that the current adaptation rules and equipment in federated U-10 competitions might not be enough to improve the teaching-learning process under the comprehensive approach. The current competition for U-10 tennis players (stage green) should be redesigned, in order to build an optimal process of affordances to develop a multidimensional positive impact during this training stage.

A shorter cricket pitch improves decision-making by junior batters

This study sought to determine whether playing on a shorter cricket pitch would lead batters to make more appropriate decisions about whether to play front foot or back foot shots. Based on an analysis of the shots played by top order batters against seam bowling in county under-10 matches, an age-specific "good length" region between 5.0 yards and 6.5 yards (4.57 to 5.94 m) from the batters' stumps was derived. This was where batters were uncertain whether to play on the front or back foot. It was then possible to define deliveries as "short" or "full" depending upon whether they bounced further from or nearer to the batter than the good length region. Club under-11 and county under-10 match data revealed that when playing on a 16-yard pitch batters played more back foot shots to short balls, and county batters also played more front foot shots to full balls compared with matches on the currently recommended 20- or 19-yard pitches. For batters, a shorter pitch should strengthen the coupling between the perception of delivery length and appropriate shot selection, and the increased task demand should lead to improved anticipation, both key features of skilled batting.

Ground reaction force, spinal kinematics and their relationship to lower back pain and injury in cricket fast bowling: A review

BACKGROUND

Fast bowlers display a high risk of lower back injury and pain. Studies report factors that may increase this risk, however exact mechanisms remain unclear.

OBJECTIVE

To provide a contemporary analysis of literature, up to April 2016, regarding fast bowling, spinal kinematics, ground reaction force (GRF), lower back pain (LBP) and pathology.

METHOD

Key terms including biomechanics, bowling, spine and injury were searched within MEDLINE, Google Scholar, SPORTDiscuss, Science Citation Index, OAIster, CINAHL, Academic Search Complete, Science Direct and Scopus. Following application of inclusion criteria, 56 studies (reduced from 140) were appraised for quality and pooled for further analysis.

RESULTS

Twelve times greater risk of lumbar injury was reported in bowlers displaying excessive shoulder counter-rotation (SCR), however SCR is a surrogate measure which may not describe actual spinal movement. Little is known about LBP specifically. Weighted averages of 5.8 ± 1.3 times body weight (BW) vertically and 3.2 ± 1.1 BW horizontally were calculated for peak GRF during fast bowling. No quantitative synthesis of kinematic data was possible due to heterogeneity of reported results.

CONCLUSIONS

Fast bowling is highly injurious especially with excessive SCR. Studies adopted similar methodologies, constrained to laboratory settings. Future studies should focus on methods to determine biomechanics during live play.

Quantifying Cricket Fast-Bowling Skill

OBJECTIVES

To evaluate the current evidence regarding the quantification of cricket fast-bowling skill.

METHODS

Studies that assessed fast-bowling skill (bowling speed and accuracy) were identified from searches in SPORTDiscus (EBSCO) in June 2017. The reference lists of identified papers were also examined for relevant investigations.

RESULTS

A total of 16 papers matched the inclusion criteria, and discrepancies in assessment procedures were evident. Differences in test environment, pitch, and cricket ball characteristics; the warm-up prior to test; test familiarization procedures; permitted run-up lengths; bowling spell length; delivery sequence; test instructions; collection of bowling speed data; and collection and reportage of bowling accuracy data were apparent throughout the literature. The reliability and sensitivity of fast-bowling skill measures have rarely been reported across the literature. Only 1 study has attempted to assess the construct validity of its skill measures.

CONCLUSIONS

There are several discrepancies in how fast-bowling skill has been assessed and subsequently quantified in the literature to date. This is a problem, because comparisons between studies are often difficult. Therefore, a strong rationale exists for the creation of match-specific standardized fast-bowling assessments that offer greater ecological validity while maintaining acceptable reliability and sensitivity of the skill measures. If prospective research can act on the proposed recommendations from this review, then coaches will be able to make more informed decisions surrounding player selection, talent identification, return to skill following injury, and the efficacy of short- and long-term training interventions for fast bowlers.

Scaling the Equipment and Play Area in Children's Sport to improve Motor Skill Acquisition: A Systematic Review

Background

This review investigated the influence of scaling sports equipment and play area (e.g., field size) on children’s motor skill acquisition.

Methods

Peer-reviewed studies published prior to February 2015 were searched using SPORTDiscus and MEDLINE. Studies were included if the research (a) was empirical, (b) involved participants younger than 18 years, (c) assessed the efficacy of scaling in relation to one or more factors affecting skill learning (psychological factors, skill performance and skill acquisition factors, biomechanical factors, cognitive processing factors), and (d) had a sport or movement skills context. Risk of bias was assessed in relation to selection bias, detection bias, attrition bias, reporting bias and other bias.

Results

Twenty-five studies involving 989 children were reviewed. Studies revealed that children preferred using scaled equipment over adult equipment (n = 3), were more engaged in the task (n = 1) and had greater self-efficacy to execute skills (n = 2). Eighteen studies demonstrated that children performed skills better when the equipment and play area were scaled. Children also acquired skills faster in such conditions (n = 2); albeit the practice interventions were relatively short. Five studies showed that scaling led to children adopting more desirable movement patterns, and one study associated scaling with implicit motor learning.

Conclusion

Most of the studies reviewed provide evidence in support of equipment and play area scaling. However, the conclusions are limited by the small number of studies that examined learning (n = 5), poor ecological validity and skills tests of few trials.

The effect of equipment scaling on children's sport performance: the case for tennis

The influence of scaling court-size and net height on children's tennis performance was examined. Sixteen boys (9.7 ± 0.5 years) had to perform a 30-min match in four different conditions, where court-size and/or net height were scaled by using a scaling ratio based on the differences in temporal demands between the children and the adult game. These 30-min matches were analysed using Tennis Analyst (FairPlay Ltd., Jindalee, QLD, Australia) software to determine typical tennis match performance characteristics. Children hit more winners, more forced errors, played more volleys, struck more shots from a comfortable height and played in a more forward court position when the net was scaled. Scaling both the court and net lead to a faster children's game, more closely approximating what is typical of the adult game. The differences between the typical tennis performance variables recorded suggested that scaling the net led to a more aggressive way of playing. Further, children enjoyed playing on the standard court-scaled net condition more than standard adult conditions. It is suggested that optimising the scaling of net height may be as critical as other task constraints, such as racquet length or court-size, as it leads to a more engaging learning environment for experienced children.

Modifying equipment in early skill development: a tennis perspective

PURPOSE

The International Tennis Federation recently launched a worldwide campaign advocating the use of equipment scaling for children learning to play tennis. The aim of this study was to investigate the influence that varying racquet sizes and ball compressions had on children's ability to play a forehand groundstroke.

METHOD

This was a quantitative repeated-measures design experiment. Children were required to perform a forehand hitting task using each of 9 combinations of tennis racquets and balls (i.e., 3 racquet sizes x 3 ball compressions). Children's hitting performance was measured using a points system. The aim for the children was to score as many points as possible. Hitting technique was measured via video replay.

RESULTS

Hitting performance was best when the smallest racquet combined with the ball with the least compression was used. The ball with the least compression also promoted 2 technique benefits: swinging the racquet from low to high and striking the ball in front and to the side of the body.

CONCLUSIONS

This study demonstrated the benefits for young children playing with scaled racquets and low-compression balls. The findings are discussed with regards to their relevance to theories of skill acquisition.

Performance accuracy and functional variability in elite and developing fast bowlers

OBJECTIVES

The relationship between performance variability and accuracy in cricket fast bowlers of different skill levels under three different task conditions was investigated. Bowlers of different skill levels were examined to observe if they could adapt movement patterns to maintain performance accuracy on a bowling skills test.

DESIGN

8 national, 12 emerging and 12 junior pace bowlers completed an adapted version of the Cricket Australia bowling skills test, in which they performed 30 trials involving short (n=10), good (n=10), and full (n=10) length deliveries.

METHODS

Bowling accuracy was recorded by digitising ball position relative to the centre of a target. Performance measures were mean radial error (accuracy), variable error (consistency), centroid error (bias), bowling score and ball speed. Radial error changes across the duration of the skills test were used to record accuracy adjustment in subsequent deliveries.

RESULTS

Elite fast bowlers performed better in speed, accuracy, and test scores than developing athletes. Bowlers who were less variable were also more accurate across all delivery lengths. National and emerging bowlers were able to adapt subsequent performance trials within the same bowling session for short length deliveries.

CONCLUSIONS

Accuracy and adaptive variability were key components of elite performance in fast bowling which improved with skill level. In this study, only national elite bowlers showed requisite levels of adaptive variability to bowl a range of lengths to different pitch locations.

Inertial measurement units furnish accurate trunk trajectory reconstruction of the sit-to-stand manoeuvre in healthy subjects

A simple inertial measurement unit (IMU) incorporating rate gyroscopes and accelerometers has been tested to investigate the trunk kinematics during the sit-to-stand. It was affixed at trunk L5 level and used for sit-to-stand position and orientation reconstruction. The method was validated with standard optoelectronic equipment and results were also compared to the ones obtained by means of a Fast Video Camera. Comparative results showed for the IMU better performance than the system based on the Fast Video Camera. During the rising the mean pitch error was always lower than 5.2 x 10(-1) degrees and the mean Euclidean error lower than 5.9 x 10(-3) m in the sagittal plane.