Fast bowling match workloads over 5-26 days and risk of injury in the following month

The relationship between bowling intensity and ground reaction force in cricket pace bowlers

This study examined the relationship between perceived bowling intensity, ball release speed and ground reaction force (measured by peak force, impulse and loading rate) in male pace bowlers. Twenty participants each bowled 36 deliveries, split evenly across three perceived intensity zones: low = 70% of maximum perceived bowling effort, medium = 85%, and high = 100%. Peak force and loading rate were significantly different across the three perceived intensity zones in the horizontal and vertical directions (Cohen's d range = 0.14-0.45, p < 0.01). When ball release speed increased, peak force and loading rate also increased in the horizontal and vertical directions (η_p² = 0.04-0.18, p < 0.01). Lastly, bowling at submaximal intensities (i.e., low - medium) was associated with larger decreases in peak horizontal force (7.9-12.3% decrease), impulse (15.8-21.4%) and loading rate (7.4-12.7%) compared to decreases in ball release speed (5.4-8.3%). This may have implications for bowling strategies implemented during training and matches, particularly for preserving energy and reducing injury risk.

Injury incidence within male elite New Zealand cricket from the early T20 era: 2009-2015

Objectives

This study aimed to describe the injury epidemiology of domestic and international level male New Zealand cricketers from seasons 2009–2010 to 2014–2015 across all match formats given the increasing popularity of T20 cricket.

Methods

Match exposure and injury surveillance data collected prospectively by New Zealand Cricket was analysed using international consensus recommendations for injury surveillance and reporting in cricket. Relationships between playing level, role and injury were statistically analysed.

Results

A total of 268 elite male New Zealand cricketers from seasons 2009–2010 to 2014–2015 were analysed from the New Zealand Cricket injury surveillance system. Total new match injury incidence rates were 37.0 and 58.0 injuries per 10 000 player hours in domestic and international cricket, respectively. Total new and recurrent match injury incidence in international cricket was approximately 1.7 times higher than domestic cricket (277.6 vs 162.8 injuries per 1000 player days). Injury prevalence rates were 7.6% and 10.0% in domestic and international cricket. The hamstring (8.2%) in domestic cricket and the groin (13.5%) in international cricket were the most injured body sites. Most match days lost in domestic cricket were to the lumbar spine (417 days), and groin in international cricket (152 days). There were statistically significant differences in injury between domestic and international level cricketers (χ²=4.39, p=0.036), and playing role (χ²=42.29, p<0.0001).

Conclusions

Total injury incidence rates in elite New Zealand cricket increased in 2009–2015 compared with previous data. International-level players and pace bowlers were the most injured individuals.

Quantifying cricket fast bowling volume, speed and perceived intensity zone using an Apple Watch and machine learning

This study examined whether an inertial measurement unit (IMU) and machine learning models could accurately measure bowling volume (BV), ball release speed (BRS), and perceived intensity zone (PIZ). Forty-four male pace bowlers wore a high measurement range, research-grade IMU (SABELSense) and a consumer-grade IMU (Apple Watch) on both wrists. Each participant bowled 36 deliveries, split into two different PIZs (Zone 1 = 70-85% of maximum bowling effort, Zone 2 = 100% of maximum bowling effort). BRS was measured using a radar gun. Four machine learning models were compared. Gradient boosting models had the best results across all measures (BV: F-score = 1.0; BRS: Mean absolute error = 2.76 km/h; PIZ: F-score = 0.92). There was no significant difference between the SABELSense and Apple Watch on the same hand when measuring BV, BRS, and PIZ. A significant improvement in classifying PIZ was observed for IMUs located on the dominant wrist. For all measures, there was no added benefit of combining IMUs on the dominant and non-dominant wrists.

The relationship between cricket participation, health and wellbeing: A scoping review

Summarising and synthesising the evidence on cricket health and wellbeing can help inform cricket stakeholders and navigate future research directions. The purpose of this study was to investigate the relationship between cricket participation, health and wellbeing at all ages and playing standards, and identify research gaps in the existing literature. A scoping review was performed from inception to March, 2020. Studies were included if they assessed a construct related to health and/or wellbeing in cricketers, available in English. 219 articles were eligible. Injury incidence per 1,000 player exposures ranged from 1.8-5.7 injuries. 48% of former cricketers experienced persistent joint pain. However, former cricketers reported greater physical activity levels and mental-components of quality of life compared to the general population. Heat injury/illness and skin cancer are concerns and require further research. Cricket participation is associated with an inherent injury risk, which may have negative implications for musculoskeletal health in later life. However, cricket participation is associated with high quality of life which can persist after retirement. Gaps in the literature include prospective studies on health and wellbeing of cricketers, female cricketers, injury prevention strategies, and the impact of cricket participation on metabolic health and lifetime physical activity.

Quantification of the demands of cricket bowling and the relationship to injury risk: a systematic review

BACKGROUND

Bowling in cricket is a complex sporting movement which, despite being well characterised, still produces a significant number of injuries each year. Fast bowlers are more likely to be injured than any other playing role. Frequency, duration, intensity and volume of bowling, which have been generalised as measurements of workload, are thought to be risk factors for injuries. Injury rates of fast bowlers have not reduced in recent years despite the implementation of various workload monitoring practices.

OBJECTIVE

To identify the variables used to quantify frequency, intensity, time and volume of bowling; and evaluate relationships between these variables and injury risk.

METHODS

Six online databases were systematically searched for studies on fast bowling that included terms related to workload. Population characteristics, variables relating to demand and their relationship to standardised definitions of physical activity were extracted from all included studies.

RESULTS

Bowling workload is typically quantified through measures of frequency, duration, or indirect intensity, with few studies reporting on bowling volume.

CONCLUSIONS

When reported on, volume was often described using imprecise or insufficient measures of intensity. There is a need to develop more appropriate measures of intensity during bowling and improve the quality of evidence to inform on bowling programme management practices.

The Relationship Between Prescribed, Perceived, and Actual Delivery Intensity in Cricket Pace Bowling

PURPOSE

To investigate the relationship between prescribed (preDI), perceived (perDI), and actual delivery intensity (actDI) in cricket pace bowling.

METHODS

Fourteen male club-standard pace bowlers (mean [SD]: age 24.2 [3.2] y) completed 1 bowling session comprising 45 deliveries. The first 15 deliveries composed the warm-up, where participants bowled 3 deliveries each at a preDI of 60%, 70%, 80%, 90%, and 95%. Bowlers reported the perDI after each delivery. The fastest delivery in the session was used as a reference to calculate relative ball-release speed for the warm-up deliveries, with this measure representing the actDI. Ball-release speed was captured by a radar gun.

RESULTS

For perDI, there was a very large relationship with preDI (rs = .90, P < .001). Similarly, for actDI, there was a large relationship with preDI (rs = .52, P < .001). Higher concordance was observed between perDI and preDI from 60% to 80% preDI. A plateau was observed for actDI from 70% to 95% preDI.

CONCLUSIONS

The relationship between perDI and actDI was very large and large with respect to preDI, indicating that both variables can be used to monitor delivery intensity against the planned intensity and thus ensure healthy training adaptation. The optimal preDI that allowed pace bowlers to operate at submaximal perDI but still achieve close to maximal ball-release speeds was 70%. Bowling at the optimal preDI may significantly reduce the psychophysiological load per delivery in exchange for a trivial loss in ball-release speed.

Can an inertial measurement unit (IMU) in combination with machine learning measure fast bowling speed and perceived intensity in cricket?

This study examined whether an inertial measurement unit (IMU), in combination with machine learning, could accurately predict two indirect measures of bowling intensity through ball release speed (BRS) and perceived intensity zone (PIZ). One IMU was attached to the thoracic back of 44 fast bowlers. Each participant bowled 36 deliveries at two different PIZ zones (Zone 1 = 24 deliveries at 70% to 85% of maximum perceived bowling effort; Zone 2 = 12 deliveries at 100% of maximum perceived bowling effort) in a random order. IMU data (sampling rate = 250 Hz) were downsampled to 125 Hz, 50 Hz, and 25 Hz to determine if model accuracy was affected by the sampling frequency. Data were analysed using four machine learning models. A two-way repeated-measures ANOVA was used to compare the mean absolute error (MAE) and accuracy scores (separately) across the four models and four sampling frequencies. Gradient boosting models were shown to be the most consistent at measuring BRS (MAE = 3.61 km/h) and PIZ (F-score = 88%) across all sampling frequencies. This method could be used to measure BRS and PIZ which may contribute to a better understanding of overall bowling load which may help to reduce injuries.

How Has Workload Been Defined and How Many Workload-Related Exposures to Injury Are Included in Published Sports Injury Articles? A Scoping Review

OBJECTIVE

To describe how workload-related exposure variables have been defined in sports injury articles, and to identify the number of workload-related exposure variables included in comparative analyses.

DESIGN

Scoping review.

LITERATURE SEARCH

PubMed, SPORTDiscus, and Scopus were systematically searched on March 13, 2020. Two reviewers independently screened the retrieved literature and selected articles for inclusion.

STUDY SELECTION CRITERIA

Prospective cohort studies using workload-related variables as the primary exposure to sports injury were eligible for inclusion.

DATA SYNTHESIS

The type (eg, distance, balls bowled) and construct of workload-related exposure variables (eg, acute-chronic workload ratio) were extracted and summarized in frequency tables.

RESULTS

A total of 648 articles were identified, and 45 were eligible for inclusion. Workload definition differed greatly, as sports- and workload-related exposure variables could be, but were not limited to, distance, balls bowled, session rating of perceived exertion, accelerations, soreness, and sleep. Within and across articles, authors used different constructs for workload-related exposure variables. For example, distance was represented as total distance, distance per week, distance per 2 weeks, and acute-chronic workload ratio. The number of workload-related exposure variables included in comparative analyses ranged from 1 to 336.

CONCLUSION

Studies used different definitions of workload-related exposure variables. The number of workload-related exposure variables in a single study ranged from 1 to 336. J Orthop Sports Phys Ther 2020;50(10):538-548. doi:10.2519/jospt.2020.9766.

Submaximal Cricket Fast Bowling Offers a Disproportionate Reduction in Loading Versus Performance: An Alternative Workload Intervention

CONTEXT

Cricket fast bowlers are particularly susceptible to lumbar spine loading and injury. Quantitative analysis of technique typically involves laboratory-based biomechanical systems with limited ecological validity, whereas contemporary developments in global positioning satellite microtechnologies facilitate an on-field evaluation of loading.

OBJECTIVE

To quantify the influence of submaximal bowling from reduced approach lengths on performance and loading.

DESIGN

Repeated-measures, field-based design.

SETTING

Regulation cricket pitch.

PARTICIPANTS

A total of 12 male cricket academy fast bowlers (18.7 [0.7] y), injury free with ≥3 years of competitive experience.

INTERVENTIONS

Each bowler wore 2 global positioning satellite units placed at C7 and L4 to measure triaxial acceleration (100 Hz). Bowlers completed an over (6 deliveries) from a randomized 3-, 6-, 9-, and 12-stride approach.

MAIN OUTCOME MEASURES

Ball speed was recorded as the performance measure, with PlayerLoad in the anteroposterior, mediolateral, and vertical planes also calculated for each delivery length.

RESULTS

In ball speed, there was a significant main effect for delivery length (P = .02), with a 3-stride approach eliciting significantly less ball speed than a 9-stride (P = .03) or 12-stride (P = .002) approach. In loading, there was a significant main effect for delivery length (P < .001) in the anteroposterior, mediolateral, and vertical planes, with loading increasing linearly as a function of delivery strides. The 6-stride approach elicited a 44% reduction in loading, with a disproportionately small 3.5% decrease in performance. There was a significant main effect for global positioning satellite location (P ≤ .023) in all planes, with L4 eliciting greater loading than C7.

CONCLUSIONS

A submaximal 6-stride approach yielded the optimum balance between reduced loading and performance inhibition. Reduced delivery length, therefore, offers an alternative to reduced overs in reducing loading in young bowlers and might also have practicable value in the rehabilitation of bowlers postinjury.

Workload Monitoring in Team Sports: Using Elite Cricket as an Example

Workload monitoring is used to assess athlete preparedness to ensure that they are optimally prepared for competition. Although many workload studies have been done, most are delimited to individual sport athletes and endurance athletes. There is also controversy regarding which measures and in what combinations they should be used. There is a paucity of literature on workload monitoring in team sports such as cricket. Cricket is an interesting and complex sport which has dimensions of many other sports (team and individual) and was the focus of this broad, narrative review. The review highlights the unique demands of the sport and why consideration of the sport in question is important. It further identifies that most of the workload research has been done on fast bowlers with debate surrounding optimal workloads. It calls for research in specific areas and importantly on other player positions considering their unique demands and identifies what can be used currently by practitioners in the field.

Audit of a cardiac screening policy for elite Australian cricketers

OBJECTIVES

To report the compliance and results of an electrocardiogram (ECG) cardiac screening program in male and female elite Australian cricketers.

DESIGN

cross-sectional study.

METHODS

Elite cricketers were offered screening in accordance with Cricket Australia policy. Players who consented provided a personal and family history, physical examination and resting 12-lead ECG. An audit (1 February 2019) examined all cardiac screening records for male and female players in all Australian Cricket state squads from 16 years upwards. Data extracted from the Cricket Australia database included the number of players who underwent screening; signed waivers opting out; and had follow-up tests. ECGs were re-reviewed according to the International Criteria.

RESULTS

710 players were included in the cohort (mean age 20.4±4.9 years, 62% male). 692 (97.5%) players underwent recommended cardiac screening or signed a waiver opting out (1.1%). 173 (24.4%) players were screened (or signed a waiver) more than once. Follow-up testing was conducted for 59 (6.9%) cases. No players were excluded from sport due to a cardiac problem and no major cardiac incidents occurred to any player in the audit cohort. Review of 830 ECGs showed benign athlete heart changes, including sinus bradycardia (33.5%), left ventricular hypertrophy (16.3%), and incomplete/partial right bundle branch block (8.4%), were common but abnormal screening ECGs were uncommon (2.0%).

CONCLUSIONS

An audit of a cardiac screening program in elite Australian cricketers found excellent compliance. A small proportion required follow-up testing and no player was excluded from sport due to a cardiac problem. ECG analysis suggested cricket is a sport of moderate cardiac demands, with benign athlete heart changes common.

Incidence and prevalence of lumbar stress fracture in English County Cricket fast bowlers, association with bowling workload and seasonal variation

OBJECTIVES

Since much of the previous epidemiological research into lumbar stress fracture was conducted, there has been a marked increase in the amount of cricket being played. The aims were to determine the incidence and prevalence of lumbar stress fracture in English County Cricket fast bowlers between 2010 and 2016, determine the association with match bowling workload and observe seasonal variation in workload and injury.

METHODS

Lumbar stress fracture incidence and prevalence rates were calculated using new international methods for epidemiology in 368 professional English fast bowlers from 2010 to 2016. Workload variables were compared between lumbar stress fracture case and non-injured control groups, before entry in a logistic regression.

RESULTS

Fifty-seven lumbar stress fractures (mean age 22.81) were reported. Injury was most common in July and September. Match incidence was 0.16 lumbar stress fractures per 10 000 deliveries, annual incidence was 2.46 lumbar stress fractures per 100 fast bowlers and annual prevalence of lumbar stress fractures was 1.67% of squad days. Significant workload variables were observed between cases and controls. A peak 7-day workload of greater than 234 deliveries significantly increased the odds of sustaining a lumbar stress fracture 11-fold compared with bowling fewer than 197 deliveries.

CONCLUSION

Lumbar stress fractures are common in young fast bowlers possibly due to immaturity of the lumbar spine. The condensed early and late-season schedule may be causing periods of overuse, resulting in an increase in incidence of lumbar stress fracture. Reduction of workload in young fast bowlers is needed to reduce incidence.

Match injuries in Sri Lankan junior cricket: A prospective, longitudinal study

OBJECTIVES

Understanding the nature of injuries in cricket is key to mitigate injury risks and prioritise preventive measures. This study aimed to identify the incidence and nature of match injuries among Sri Lankan junior cricketers.

DESIGN

Longitudinal follow-up study with prospective in-season data collection.

METHODS

A national survey of schoolboy, division-1 cricket teams in under-15 and under-17 age groups. Using a paper-based questionnaire, distributed to school-teams at the start of the 2016 cricket season, respondents recorded any injuries, including the site, type and mechanism. Match injury incidence rates (match-IIR) (injuries/100 match-player-days) were calculated overall, by position and for match time loss (MTL) and non-MTL injuries.

RESULTS

From 59 school-teams, 573 players responded, with 404 players reporting 744 injuries in 648 matches. The match-IIR was 28.0 injuries/100 match-player-days (95% CI=26.0-30.2). The highest match-IIR was reported among fielders (46.0% of all injuries sustained; match-IIR=12.9) compared with batters (25.4%; match-IIR=7.1) and bowlers (20.3%; match-IIR=5.7). Abrasions and bruises to the knee or elbow were the most common injuries among fielders, with the majority being non-MTL injuries.

CONCLUSIONS

Almost half (46.0%) of all injuries were to fielders, and more research into their severity and mechanisms is needed to identify the need for, and design of, preventive measures. Batters sustained a relatively large number of facial-organ injuries from being struck by the ball, presenting a need to evaluate the use and appropriateness of helmets by Sri Lankan junior cricketers. Similar to other junior cricket studies, the most common injuries among bowlers were strains and sprains, mainly affecting the lower limbs and lower back.

Cricket fast bowling detection in a training setting using an inertial measurement unit and machine learning

Fast bowlers are at a high risk of overuse injuries. There are specific bowling frequency ranges known to have negative or protective effects on fast bowlers. Inertial measurement units (IMUs) can classify movements in sports, however, some commercial products can be too expensive for the amateur athlete. As a large number of the world's population has access to an IMU (e.g. smartphones), a system that works on a range of different IMUs may increase the accessibility of automated workload monitoring in sport. Seventeen elite fast bowlers in a training setting were used to train and/or validate five machine learning models by bowling and performing fielding drills. The accuracy of machine learning models trained using data from all three bowling phases (pre-delivery, delivery and post-delivery) were compared to those trained using only the delivery phase at a sampling rate of 250 Hz. Next, models were trained using data down-sampled to 125 Hz, 50 Hz, and 25 Hz to mimic results from lower specification sensors. Models trained using only the delivery phase showed similar accuracy (> 95%) to those trained using all three bowling phases. When delivery-phase data were down-sampled, the accuracy was maintained across all models and sampling frequencies (>96%).

MRI bone marrow oedema precedes lumbar bone stress injury diagnosis in junior elite cricket fast bowlers

OBJECTIVES

Lumbar bone stress injury ('bone stress injury') is common in junior fast bowlers. The repetitive loading of cricket fast bowling may cause bone marrow oedema (BMO), detectable on MRI, before the bowler suffers from symptomatic bone stress injury. We investigated the temporal relationship between BMO, bone stress injury, along with bowling workload correlates, in elite junior fast bowlers throughout a cricket season.

METHODS

65 junior fast bowlers were prospectively monitored for one 8-month cricket season. For research purposes, participants had up to six MRI scans at set times in the season; findings were withheld from them and their clinicians. Standard practices for bowling workload monitoring and injury diagnosis were followed.

RESULTS

15 (23%) participants developed bone stress injury during the study. All 15 of these participants had BMO detected on at least one of the preceding MRI scans, including the scan immediately prior to diagnosis. The risk of BMO progressing to bone stress injury during the season was greatest for participants with BMO present 2 weeks prior to the national championship tournament (period of high load) (RR=18.9, OR=44.8). Both bone stress injury and BMO were associated with bowling a higher percentage of days in training and having a shorter bowling break during the season. The number of balls bowled and acute-to-chronic workload were not associated with imaging abnormalities or injury.

CONCLUSION

The presence of BMO on MRI in asymptomatic junior cricket fast bowlers confers a very high risk for bone stress injury. The risk may be managed by MRI screening and monitoring bowling frequency.

A Kinetic Model Describing Injury-Burden in Team Sports

BACKGROUND

Injuries in team sports are normally characterised by the incidence, severity, and location and type of injuries sustained: these measures, however, do not provide an insight into the variable injury-burden experienced during a season. Injury burden varies according to the team's match and training loads, the rate at which injuries are sustained and the time taken for these injuries to resolve. At the present time, this time-based variation of injury burden has not been modelled.

OBJECTIVES

To develop a kinetic model describing the time-based injury burden experienced by teams in elite team sports and to demonstrate the model's utility.

METHODS

Rates of injury were quantified using a large eight-season database of rugby injuries (5253) and exposure (60,085 player-match-hours) in English professional rugby. Rates of recovery from injury were quantified using time-to-recovery analysis of the injuries.

RESULTS

The kinetic model proposed for predicting a team's time-based injury burden is based on a composite rate equation developed from the incidence of injury, a first-order rate of recovery from injury and the team's playing load. The utility of the model was demonstrated by examining common scenarios encountered in elite rugby.

CONCLUSIONS

The kinetic model developed describes and predicts the variable injury-burden arising from match play during a season of rugby union based on the incidence of match injuries, the rate of recovery from injury and the playing load. The model is equally applicable to other team sports and other scenarios.

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.

Injury rate and patterns of Sydney grade cricketers: a prospective study of injuries in 408 cricketers

Background

The grade cricket competition, also known as premier cricket, supplies players to the state and national teams in Australia. The players involved are generally high-performing amateur (subelite) club cricketers. However, to date, there is no study on the injury epidemiology of Australian grade cricket.

Aim

To conduct injury surveillance across all teams playing Sydney Grade Cricket (SGC) competition during the 2015–2016 season.

Methods

A cohort study was conducted to track injuries in 408 male cricketers in 20 teams playing SGC competition. Players were tracked through the MyCricket website’s scorebook every week. Cricket New South Wales physiotherapists were alerted if there were changes to the playing XI from the last game. If any changes were made due to injury, then an injury incident was registered.

Results

During the course of the season, a total of 86 injuries were registered from 65 players, resulting in a loss of 385 weeks of play. The overall injury incidence rate was 35.54 injuries/10 000 playing hours with an average weekly injury prevalence of 4.06%. Lower back injuries (20%) were the most common injuries followed by foot (14%), hand (13.75%), knee (7.5%) and calf (7.5%). Linear regression analysis showed that the likelihood of injury increased as the mean age of the teams increased (R=0.5, p<0.05).

Conclusion

The injury rate in SGC is lower than that reported at elite level. However, the high rate of lower back injuries (20%) highlights an area of concern in this cohort. High workloads or inadequate physical conditioning may contribute to such injuries. This study sets the foundation for understanding injury epidemiology in grade cricket and examines the links between injury and performance, these results may assist coaches and administrators to develop and implement cricket-specific injury prevention programmes.

Training Load and Fatigue Marker Associations with Injury and Illness: A Systematic Review of Longitudinal Studies

Background

Coaches, sport scientists, clinicians and medical personnel face a constant challenge to prescribe sufficient training load to produce training adaption while minimising fatigue, performance inhibition and risk of injury/illness.

Objective

The aim of this review was to investigate the relationship between injury and illness and longitudinal training load and fatigue markers in sporting populations.

Methods

Systematic searches of the Web of Science and PubMed online databases to August 2015 were conducted for articles reporting relationships between training load/fatigue measures and injury/illness in athlete populations.

Results

From the initial 5943 articles identified, 2863 duplicates were removed, followed by a further 2833 articles from title and abstract selection. Manual searching of the reference lists of the remaining 247 articles, together with use of the Google Scholar ‘cited by’ tool, yielded 205 extra articles deemed worthy of assessment. Sixty-eight studies were subsequently selected for inclusion in this study, of which 45 investigated injury only, 17 investigated illness only, and 6 investigated both injury and illness. This systematic review highlighted a number of key findings, including disparity within the literature regarding the use of various terminologies such as training load, fatigue, injury and illness. Athletes are at an increased risk of injury/illness at key stages in their training and competition, including periods of training load intensification and periods of accumulated training loads.

Conclusions

Further investigation of individual athlete characteristics is required due to their impact on internal training load and, therefore, susceptibility to injury/illness.

Trunk Side Strain Has a High Incidence in First-Class Cricket Fast Bowlers in Australia and England

OBJECTIVE

To investigate the past incidence of side strain injury and its associated factors in first-class cricket fast bowlers in Australia and England.

DESIGN

Retrospective case series.

SETTING

Professional cricket.

PARTICIPANTS

Cricket fast bowlers who were professionally contracted full time at first-class level in Australia and England in 2011. All bowlers were male and aged 18 or older. A bowler was defined as a fast bowler if the wicketkeeper would take their stance back from the stumps. There were 207 participants.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The association between bowling arm, player height, active trunk lateral flexion range of motion, side bridge endurance, volume of first-class cricket played, and the history of injury was determined.

RESULTS

Over half of the bowlers had sustained at least 1 side strain in their career. Seventy-seven percent of primary injuries occurred in bowlers aged 24 or under. A higher proportion of injured bowlers had reached first-class volume in their career. Recurrence occurred in 30% of bowlers, with over 30% of these bowlers sustaining at least 1 further recurrence. Nearly half of all recurrences occurred within 2 years with a further quarter in the next year. The injury was not associated with any measured factors.

CONCLUSIONS

Side strain is a common injury among first-class cricket fast bowlers, especially at younger ages. It was associated with the volume of first-class cricket played. Recurrence was common and occurred most frequently in the first 2 years after primary injury.

Monitoring Workload in Throwing-Dominant Sports: A Systematic Review

BACKGROUND

The ability to monitor training load accurately in professional sports is proving vital for athlete preparedness and injury prevention. While numerous monitoring techniques have been developed to assess the running demands of many team sports, these methods are not well suited to throwing-dominant sports that are infrequently linked to high running volumes. Therefore, other techniques are required to monitor the differing demands of these sports to ensure athletes are adequately prepared for competition.

OBJECTIVE

To investigate the different methodologies used to quantitatively monitor training load in throwing-dominant sports.

METHODS

A systematic review of the methods used to monitor training load in throwing-dominant sports was conducted using variations of terms that described different load-monitoring techniques and different sports. Studies included in this review were published prior to June 2015 and were identified through a systematic search of four electronic databases including Academic Search Complete, CINAHL, Medline and SPORTDiscus. Only full-length peer-reviewed articles investigating workload monitoring in throwing-dominant sports were selected for review.

RESULTS

A total of 8098 studies were initially retrieved from the four databases and 7334 results were removed as they were either duplicates, review articles, non-peer-reviewed articles, conference abstracts or articles written in languages other than English. After screening the titles and abstracts of the remaining papers, 28 full-text papers were reviewed, resulting in the identification of 20 articles meeting the inclusion criteria for monitoring workloads in throwing-dominant sports. Reference lists of selected articles were then scanned to identify other potential articles, which yielded one additional article. Ten articles investigated workload monitoring in cricket, while baseball provided eight results, and handball, softball and water polo each contributed one article. Results demonstrated varying techniques used to monitor workload and purposes for monitoring workload, encompassing the relationship between workload and injury, individual responses to workloads, the effect of workload on subsequent performance and the future directions of workload-monitoring techniques.

CONCLUSION

This systematic review highlighted a number of simple and effective workload-monitoring techniques implemented across a variety of throwing-dominant sports. The current literature placed an emphasis on the relationship between workload and injury. However, due to differences in chronological and training age, inconsistent injury definitions and time frames used for monitoring, injury thresholds remain unclear in throwing-dominant sports. Furthermore, although research has examined total workload, the intensity of workload is often neglected. Additional research on the reliability of self-reported workload data is also required to validate existing relationships between workload and injury. Considering the existing disparity within the literature, it is likely that throwing-dominant sports would benefit from the development of an automated monitoring tool to objectively assess throwing-related workloads in conjunction with well-established internal measures of load in athletes.

Incidence and prevalence of elite male cricket injuries using updated consensus definitions

BACKGROUND

T20 (Twenty20 or 20 over) cricket has emerged in the last decade as the most popular form of cricket (in terms of spectator attendances). International consensus cricket definitions, first published in 2005, were updated in 2016 to better reflect the rise to prominence of T20 cricket.

METHODS

Injury incidence and prevalence rates were calculated using the new international methods and units for elite senior male Australian cricketers over the past decade (season 2006-2007 to season 2015-2016 inclusive).

RESULTS

Over the past 10 seasons, average match injury incidence, for match time-loss injuries, was 155 injuries/1,000 days of play, with the highest daily rates in 50-over cricket, followed by 20-over cricket and First-Class matches. Annual injury incidence was 64 injuries/100 players per season, and average annual injury prevalence was 12.5% (although fast bowlers averaged 20.6%, much higher than other positions). The most common injury was the hamstring strain (seasonal incidence 8.7 injuries/100 players per season). The most prevalent injury was lumbar stress fractures (1.9% of players unavailable at all times owing to these injuries, which represents 15% of all missed playing time).

DISCUSSION

The hamstring strain has emerged from being one of the many common injuries in elite cricket a decade ago to being clearly the most common injury in the sport at the elite level. This is presumably in association with increased T20 cricket. Lumbar stress fractures in fast bowlers are still the most prevalent injury in the sport of cricket at the elite level, although these injuries are more associated with high workloads arising from the longer forms of the game. Domestic and international matches have very similar match injury incidence rates across the formats, but injury prevalence is higher in international players as they play for most of the year without a substantial off-season.

Side strain in sport: a narrative review of pathomechanics, diagnosis, imaging and management for the clinician

OBJECTIVES

To provide an overview of the published literature on epidemiology, pathomechanics and risk factors for side strain injury in sport, complemented by clinical perspectives of diagnosis and management strategies that are not covered in the literature.

DESIGN

Narrative review METHODS: A review of the literature was completed with all studies on side strain up until October 2015 included. As the studies were unable to be synthesised the findings were placed in a clinical context. As there were no papers on the management of side strain a clinical perspective from cricket was included.

RESULTS

Literature on side strain in sport is sparse with only nine papers dedicated to the injury. These comprise epidemiology, case studies, small case series and clinical reviews on imaging, injection and surgery. The epidemiology demonstrates that side strain is most commonly associated with cricket and baseball. Side strain typically occurs acutely mostly on the side contralateral to the dominant arm in athletes. Diagnosis is clinical with consistent imaging features that typically demonstrate a tear of the internal oblique from the lower ribs. Recovery periods can be prolonged and recurrence may occur. There has been no research on the management of side strain and the relationship between clinical assessment and imaging findings and time to return to play or risk of recurrence.

CONCLUSIONS

Side strain injury is prevalent in cricket and baseball. Recovery is extended and recurrence may occur. Incidence appears to be increasing. Knowledge on side strain is limited.

How much is too much? (Part 1) International Olympic Committee consensus statement on load in sport and risk of injury

Athletes participating in elite sports are exposed to high training loads and increasingly saturated competition calendars. Emerging evidence indicates that poor load management is a major risk factor for injury. The International Olympic Committee convened an expert group to review the scientific evidence for the relationship of load (defined broadly to include rapid changes in training and competition load, competition calendar congestion, psychological load and travel) and health outcomes in sport. We summarise the results linking load to risk of injury in athletes, and provide athletes, coaches and support staff with practical guidelines to manage load in sport. This consensus statement includes guidelines for (1) prescription of training and competition load, as well as for (2) monitoring of training, competition and psychological load, athlete well-being and injury. In the process, we identified research priorities.

International consensus statement on injury surveillance in cricket: a 2016 update

Cricket was the first sport to publish recommended methods for injury surveillance in 2005. Since then, there have been changes to the nature of both cricket and injury surveillance. Researchers representing the major cricket playing nations met to propose changes to the previous recommendations, with an agreed voting block of 14. It was decided that 10 of 14 votes (70%) were required to add a new definition element and 11 of 14 (80%) were required to amend a previous definition. In addition to the previously agreed 'Match time-loss' injury, definitions of 'General time-loss', 'Medical presentation', 'Player-reported' and 'Imaging-abnormality' injuries are now provided. Further, new injury incidence units of match injuries per 1000 player days, and annual injuries per 100 players per year are recommended. There was a shift towards recommending a greater number of possible definitions, due to differing contexts and foci of cricket research (eg, professional vs amateur; injury surveillance systems vs specific injury category studies). It is recommended that researchers use and report as many of the definitions as possible to assist both comparisons between studies within cricket and with those from other sports.

Has the athlete trained enough to return to play safely? The acute:chronic workload ratio permits clinicians to quantify a player's risk of subsequent injury

The return to sport from injury is a difficult multifactorial decision, and risk of reinjury is an important component. Most protocols for ascertaining the return to play status involve assessment of the healing status of the original injury and functional tests which have little proven predictive ability. Little attention has been paid to ascertaining whether an athlete has completed sufficient training to be prepared for competition. Recently, we have completed a series of studies in cricket, rugby league and Australian rules football that have shown that when an athlete's training and playing load for a given week (acute load) spikes above what they have been doing on average over the past 4 weeks (chronic load), they are more likely to be injured. This spike in the acute:chronic workload ratio may be from an unusual week or an ebbing of the athlete's training load over a period of time as in recuperation from injury. Our findings demonstrate a strong predictive (R(2)=0.53) polynomial relationship between acute:chronic workload ratio and injury likelihood. In the elite team setting, it is possible to quantify the loads we are expecting athletes to endure when returning to sport, so assessment of the acute:chronic workload ratio should be included in the return to play decision-making process.