Lumbar load in adolescent fast bowlers: A prospective injury study

Intrinsic variables associated with low back pain and lumbar spine injury in fast bowlers in cricket: a systematic review

BACKGROUND

Lumbar spine injuries in fast bowlers account for the greatest missed playing time in cricket. A range of extrinsic and intrinsic variables are hypothesised to be associated with low back pain and lumbar spine injury in fast bowlers, and an improved understanding of intrinsic variables is necessary as these may alter load tolerance and injury risk associated with fast bowling. This review critically evaluated studies reporting intrinsic variables associated with low back pain and lumbar spine injury in fast bowlers and identified areas for future investigation.

METHODS

OVID Medline, EMBASE, SPORTDiscus, CINAHL, Web of Science and SCOPUS databases were last searched on 3 June 2022 to identify studies investigating intrinsic variables associated with low back pain and lumbar spine injury in cricket fast bowlers. Terms relevant to cricket fast bowling, and intrinsic variables associated with lumbar spine injury and low back pain in fast bowlers were searched. 1,503 abstracts were screened, and 118 full-text articles were appraised to determine whether they met inclusion criteria. Two authors independently screened search results and assessed risk of bias using a modified version of the Quality in Prognostic Studies tool.

RESULTS

Twenty-five studies met the inclusion criteria. Overall, no included studies demonstrated a low risk of bias, two studies were identified as moderate risk, and twenty-three studies were identified as high risk. Conflicting results were reported amongst studies investigating associations of fast bowling kinematics and kinetics, trunk and lumbar anatomical features, anthropometric traits, age, and neuromuscular characteristics with low back pain and lumbar spine injury.

CONCLUSION

Inconsistencies in results may be related to differences in study design, injury definitions, participant characteristics, measurement parameters, and statistical analyses. Low back pain and lumbar spine injury occurrence in fast bowlers remain high, and this may be due to an absence of low bias studies that have informed recommendations for their prevention. Future research should employ clearly defined injury outcomes, analyse continuous datasets, utilise models that better represent lumbar kinematics and kinetics during fast bowling, and better quantify previous injury, lumbar anatomical features and lumbar maturation.

TRIAL REGISTRATION

Open Science Framework https://doi.org/10.17605/OSF.IO/ERKZ2 .

Is MRI screening for bone marrow oedema useful in predicting lumbar bone stress injuries in adult male professional cricketers? A New Zealand pilot study

OBJECTIVES

The aims were to (1) prospectively observe the incidence of bone marrow oedema in asymptomatic adult male domestic professional cricketers during a season and evaluate its relationship to the development of lumbar bone stress injury and (2) further understand the practicalities of implementing a Magnetic Resonance Imaging-based screening program to prevent lumbar bone stress injury in New Zealand cricket.

DESIGN

Prospective observational cohort.

METHODS

Adult male pace bowlers received 6-weekly pre-planned Magnetic Resonance Imaging scans over a single season to determine the presence and intensity of bone marrow oedema in the posterior vertebral arches of the lumbar spine. The participants bowling volume and back pain levels were monitored prospectively.

RESULTS

22 participants (mean age 25.3 years (range 20-32 years)) completed all 4 scans. Ten participants had a prior history of lumbar bone stress injury. Ten participants (45 %, 95 % confidence interval 24-68 %) had bone marrow oedema evident on at least one scan, with 9 (41 %) participants recording a bone marrow oedema intensity ≥ 2 and 5 (23 %) participants demonstrated an intensity ≥ 3. During the study one participant was diagnosed with a lumbar bone stress reaction. No participants developed a lumbar bone stress fracture.

CONCLUSIONS

Due to the lower incidence of lumbar bone stress injuries in adult bowlers coupled with uncertainty over appropriate threshold values for bone marrow oedema intensity, implementation of a resource intense screening program aimed at identifying adult domestic cricketers at risk of developing a lumbar bone stress injury is not currently supported.

Kinematic differences between left- and right-handed cricket fast bowlers during the bowling action

Background

Despite differences between left- and right-handed athletes in other sports, minimal evidence exists regarding biomechanical similarities and differences between left- and right-handed cricket fast bowlers performing an equivalent task.

Objectives

This study aimed to compare the kinematics between left and right-handed fast bowlers performing an equivalent task (i.e. bowling 'over the wicket' to a batter of the same handedness as the bowler).

Methods

Full body, three-dimensional kinematic data for six left-handed and 20 right-handed adolescent, male, fast bowlers were collected using the Xsens inertial measurement system. Time-normalised joint and segment angle time histories from back foot contact to follow-through ground contacts were compared between groups via statistical parametric mapping. Whole movement and subphase durations were also compared.

Results

Left-handed players displayed significantly more trunk flexion from 49%-56% of the total movement (ball release occurred at 54%; p = 0.037) and had shorter back foot contact durations on average (0.153 vs 0.177 s; p = 0.036) compared to right-handed players.

Conclusion

Left- and right-handed bowlers displayed similar sagittal plane kinematics but appeared to use non-sagittal plane movements differently around the time of ball release. The kinematic differences identified in this study can inform future research investigating the effect of hand dominance on bowling performance and injury risk.

Cricket fast bowling: The relationship between range of motion and key performance and injury technique characteristics

Fast bowling technique characteristics associated with performance and injury have been established; however, the effect of joint range of motion (ROM) on technique remains unknown. This study aimed to investigate ROM and its effect on fast bowling technique. Eighteen ROM measures and thirteen technique parameters were determined for 45 elite male fast bowlers. Twenty-three significant correlations were found between the shoulder, hip, and ankle ROM measures and technique parameters (r = 0.300-0.452; p < 0.05). Shoulder ROM was observed to have the highest number of correlations with fast bowling technique. Increased internal rotation, less external rotation, and greater total arc of rotation were associated with technique characteristics previously linked with increased ball release speed and decreased lumbar stress injury risk. Although hip and ankle ROM were also correlated with technique, their association is yet to be understood. Future research should aim to determine the impact of ROM on fast bowling movement patterns. This knowledge is likely to be useful in enhancing the coaching and rehabilitation of fast bowlers from lumbar stress injuries.

Prevention of Secondary Injury after Anterior Cruciate Ligament Reconstruction: Relationship between Pelvic-Drop and Dynamic Knee Valgus

(1) Background: Optimal neuromuscular, Lumbo-Pelvic-Hip Complex, and lower extremity control are associated with decreased risk factors for secondary anterior cruciate ligament (ACL) injury. This study aimed to analyze any asymmetries and malalignments in the Lumbo-Pelvic-Hip Complex and the lower limbs at 6 months after ACL reconstruction (ACLR). (2) Methods: We conducted an exploratory retrospective observational single-center study in patients during the outpatient postoperative rehabilitation program at ICOT (Latina, Italy). From January 2014 to June 2020, 181 patients were recruited, but only 100 patients (86 male 28 ± 0.6 years, 178 ± 0.5 height; 14 female 24 ± 2.0 years, 178 ± 3.0 height) were eligible for the inclusion criteria and studied 6 months after ACL reconstruction surgery. (3) Statistical analysis: Student's t-tests and Pearson's product-moment correlation coefficient were used to determine significant differences between affected and non-affected limbs and variables' association. (4) Results: The study shows a decrease in neuromuscular control of the Lumbo-Pelvic-Hip Complex and dynamic adaptive valgus of the knee at 6 months after ACLR (mean difference between pathological and healthy limb of dynamic adaptive valgus was -10.11 ± 8.19° 95% CI -14.84 to -9.34; mean value was 16.3 ± 6.8° 95% CI 14.04 to 18.55 for healthy limb and 4.2 ± 3.1° 95% CI 3.15 to 5.21 for pathological limb, p < 0.0001). The results also showed a relationship between dynamic adaptive valgus and contralateral pelvic drop (r = 0.78, 95% CI 0.62 to 0.88, magnitude of correlation very large). (5) Conclusions: The analysis showed an associative correlation between decreased postural control of the pelvic girdle and dynamic adaptive valgus of the knee in 38% of patients; this study highlights the usefulness of the Single-Leg Squat Test (SLST) as a clinical/functional assessment to evaluate the rehabilitation process and as a preventive tool to reduce the risk of second ACL injuries during the return to sport.

Comparing tibial accelerations between delivery and follow-through foot strikes in cricket pace bowling

Foot strikes of the pace-bowling delivery stride produce large ground reaction forces, which may be linked to injury, yet the biomechanics of the follow-through are unknown. This study assessed tibial accelerations across the delivery and follow-through foot strikes in pace bowlers and evaluated relationships between these measures and five common pace-bowling intensity metrics. Fifteen sub-elite male pace bowlers performed deliveries at warm-up, match, and maximal intensities. Tibial accelerations were measured using tibial-mounted inertial measurement units and recorded at back- and front-foot initial and re-contacts. A trunk-worn global navigation satellite system unit measured PlayerLoad™, run-up speed, and distance. Ball speed and perceived exertion measures were also recorded. A linear mixed model showed statistical significance of prescribed intensities (p < .001) and foot strike for tibial acceleration (p < .001). Tibial accelerations showed positive increases with changes in prescribed intensity (p < .05). The greatest magnitude of tibial acceleration was found at back foot re-contact (mean ± SD; 1139 ± 319 m/s2). Repeated-measures correlations of tibial acceleration between foot contacts were weak (r = 0.2-0.4). The greatest magnitude of tibial acceleration reported at back foot re-contact may have implications for injury incidence, representing an important avenue for future pace bowling research.

Incidence, prevalence and risk factors for low back pain in adolescent athletes: a systematic review and meta-analysis

OBJECTIVE

To investigate the incidence, prevalence, risk factors and morphological presentations of low back pain (LBP) in adolescent athletes.

DESIGN

Systematic review with meta-analysis.

DATA SOURCES

Medline, Embase, CINAHL via EBSCO, Web of Science, Scopus.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies evaluating the incidence and/or prevalence of LBP in adolescent athletes across all sports.

RESULTS

There were 80 studies included. The pooled incidence estimate of LBP in adolescent athletes was 11% (95% CI 8% to 13%, I²=0%) for 2 years, 36.0% (95% CI 4% to 68%, I²=99.3%) for 12 months and 14% (95% CI 7% to 22%, I²=76%) for 6 months incidence estimates. The pooled prevalence estimate of LBP in adolescent athletes was 42% (95% CI 29% to 55%, I²=96.6%) for last 12 months, 46% (95% CI 41.0% to 52%, I²=56%) for last 3 months and 16% (95% CI 9% to 23%, I²=98.3%) for point prevalence. Potential risk factors were sport participation, sport volume/intensity, concurrent lower extremity pain, overweight/high body mass index, older adolescent age, female sex and family history of LBP. The most common morphology reported was spondylolysis. Methodological quality was deemed high in 73% of cross-sectional studies and in 30% of cohort studies. Common reasons for downgrading at quality assessment were use of non-validated survey instruments and imprecision or absence of LBP definition.

SUMMARY/CONCLUSION

LBP is common among adolescent athletes, although incidence and prevalence vary considerably due to differences in study methodology, definitions of LBP and data collection.

PROSPERO REGISTRATION NUMBER

CRD42020157206.

Measurement of uni-planar and sport specific trunk motion using magneto-inertial measurement units: The concurrent validity of Noraxon and Xsens systems relative to a retro-reflective system

BACKGROUND

There is a range of magneto-inertial measurement unit (MIMU) systems commercially available, however sensor specifications and fusion methods vary considerably between manufacturers. Such variability can influence the concurrent validity of MIMUs relative to reference standard measurement devices. Different MIMUs have been compared during static or low-velocity conditions, with higher-velocity movements assessed in robotic-based studies. However, there is a need for the concurrent validity of higher-velocity movements to be established in human-based studies.

RESEARCH QUESTION

This study aimed to assess the concurrent validity of two commercial MIMU systems (Noraxon and Xsens), relative to a 'gold-standard' retro-reflective motion capture system, when measuring trunk angles during uni-planar range of motion (ROM) and cricket bowling, which involves high-speed, multi-planar movements.

METHODS

For this criterion-based validity study, both MIMU systems incorporated comparable sensor specifications and employed Kalman filter sensor fusion algorithms. The MIMU based angles were compared with angles derived from concurrently captured three-dimensional retro-reflective data for 10 fast-medium bowlers. Statistical parametric mapping and root mean squared differences (RMSD) were computed for both MIMU systems.

RESULTS

One-dimensional statistical parametric mapping showed no significant differences for angles from both MIMU systems when compared with retro-reflective based angle outputs. The MIMU systems produced ROM RMSDs between 1.4 ± 1.0° and 2.6 ± 1.5°. One system displayed RMSDs between 4.6 ± 1.4° and 7.4 ± 1.9° during bowling, indicating functionally relevant differences to retro-reflective derived angles. There were some small but statistically significant differences in RMSDs between the MIMU systems.

SIGNIFICANCE

MIMU-based angle accuracy is poorer during high-speed, multi-planar movement than uni-planar tasks. Comparable MIMU systems can produce varying measurements during ROM and bowling tasks. It is likely that varying sample rates and sensor fusion algorithm parameters contributed to the differences.

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.

Lumbar Bone Mineral Adaptation: The Effect of Fast Bowling Technique in Adolescent Cricketers

INTRODUCTION

Localised bone mineral density (BMD) adaptation of the lumbar spine, particularly on the contralateral side to the bowling arm, has been observed in elite male cricket fast bowlers. No study has investigated this in adolescents, or the role of fast bowling technique on lumbar BMD adaptation. This study aims to investigate lumbar BMD adaptation in adolescent cricket fast bowlers, and its relationship with fast bowling technique.

METHODS

39 adolescent fast bowlers underwent antero-posterior DXA scan of their lumbar spine. Hip, lumbopelvic and thoracolumbar joint kinematics, and vertical ground reaction kinetics were determined using 3D motion capture and force plates. Significant partial (covariate: fat free mass) and bivariate correlations of the technique parameters with whole lumbar (L1-L4) BMD and BMD asymmetry (L3 and L4) were advanced as candidate variables for multiple stepwise linear regression.

RESULTS

Adolescent fast bowlers demonstrated high lumbar Z-Scores (+1.0; 95%CI: 0.7 - 1.4) and significantly greater BMD on the contralateral side of L3 (9.0%; 95%CI: 5.8 - 12.1%) and L4 (8.2%; 95%CI: 4.9 - 11.5%). Maximum contralateral thoracolumbar rotation and maximum ipsilateral lumbopelvic rotation in the period between back foot contact (BFC) and ball release (BR), as well as contralateral pelvic drop at front foot contact (FFC), were identified as predictors of L1-L4 BMD, explaining 65% of the variation. Maximum ipsilateral lumbopelvic rotation between BFC and BR, as well as ipsilateral lumbopelvic rotation and contralateral thoracolumbar side flexion at BR, were predictors of lumbar asymmetry within L3 and L4.

CONCLUSION

Thoracolumbar and lumbopelvic motion are implicated in the aetiology of the unique lumbar bone adaptation observed in fast bowlers whereas vertical ground reaction force, independent of body mass, was not. This may further implicate the osteogenic potential of torsional rather than impact loading in exercise-induced adaptation.

The impact of COVID-19 related disruption on injury rates in elite men's domestic cricket

This study aimed to investigate the impact of COVID-19 enforced prolonged training disruption and shortened competitive season, on in-season injury and illness rates. Injury incidence and percent proportion was calculated for the 2020 elite senior men's domestic cricket season and compared to a historical average from five previous regular seasons (2015 to 2019 inclusive). The injury profile for the shortened 2020 season was generally equivalent to what would be expected in a regular season, except for a significant increase in medical illness as a proportion of time loss (17% compared to historic average of 6%) and in-season days lost (9% compared to historic average of 3%) due to COVID-19 related instances (most notably precautionary isolation due to contact with a confirmed or suspected COVID-19 case). There was a significant increase in the proportion of in-season days lost to thigh injuries (24% compared to 9%) and a significant decrease in the proportion of days lost to hand (4% compared to 12%) and lumbar spine (7% compared to 21%) injuries. These findings enhance understanding of the impact prolonged period of training disruption and shortened season can have on cricket injuries and the challenges faced by practitioners under such circumstances.

Functional calibration does not improve the concurrent validity of magneto-inertial wearable sensor-based thorax and lumbar angle measurements when compared with retro-reflective motion capture

 Magneto-inertial measurement unit (MIMU) systems allow calculation of simple sensor-to-sensor Euler angles, though this process does not address sensor-to-segment alignment, which is important for deriving meaningful MIMU-based kinematics. Functional sensor-to-segment calibrations have improved concurrent validity for elbow and knee angle measurements but have not yet been comprehensively investigated for trunk or sport-specific movements. This study aimed to determine the influence of MIMU functional calibration on thorax and lumbar joint angles during uni-planar and multi-planar, sport-specific tasks. It was hypothesised that functionally calibrating segment axes prior to angle decomposition would produce smaller differences than a non-functional method when both approaches were compared with concurrently collected 3D retro-reflective derived angles. Movements of 10 fast-medium cricket bowlers were simultaneously recorded by MIMUs and retro-reflective motion capture. Joint angles derived from four different segment definitions were compared, with three incorporating functionally defined axes. Statistical parametric mapping and root mean squared differences (RMSD) quantified measurement differences one-dimensionally and zero-dimensionally, respectively. Statistical parametric mapping found no significant differences between MIMU and retro-reflective data for any method across bowling and uni-planar trunk movements. The RMSDs for the functionally calibrated methods and non-functional method were not significantly different. Functional segment calibration may be unnecessary for MIMU-based measurement of thorax and lumbar joint angles.

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.

Validity and reliability of innovative field measurements of tibial accelerations and spinal kinematics during cricket fast bowling

The use of inertial sensors in fast bowling analysis may offer a cheaper and portable alternative to current methodologies. However, no previous studies have assessed the validity and reliability of such methods. Therefore, this study aimed to assess the validity and reliability of collecting tibial accelerations and spinal kinematics using inertial sensors during in vivo fast bowling. Thirty-five elite male fast bowlers volunteered for this study. An accelerometer attached to the skin over the tibia was used to determine impacts and inertial sensors over the S1, L1 and T1 spinous processes used to derive the relative kinematics. These measurements were compared to optoelectronic and force plate data for validity analysis. Most acceleration and kinematics variables measured report significant correlations > 0.8 with the corresponding gold standard measurement, with intraclass correlation coefficients greater than 0.7. Low standard error of measurement and consequently small minimum detectable change (MDC) values were also observed. This study demonstrates that inertial sensors are as valid and reliable as current methods of fast bowling analysis and may provide some advantages over traditional methods. The novel metrics and methods described in this study may aid coaches and practitioners in the design and monitoring of fast bowling technique.

Graphical abstract illustrating the synopsis of the findings from this paper.

The standing knee lift test is not a useful screening tool for time loss from low back pain in youth basketball and floorball players

OBJECTIVES

The aim of this study was to investigate the association between pelvic kinematics during the standing knee lift (SKL) test and low back pain (LBP) in youth floorball and basketball players.

DESIGN

A prospective cohort study.

SETTING

Finnish elite youth floorball and basketball players.

PARTICIPANTS

Finnish elite youth female and male floorball and basketball players (n = 258, mean age 15.7 ± 1.8).

MAIN OUTCOME MEASURES

LBP resulting in time loss from practice and games was recorded over a 12-month period and verified by a study physician. Associations between LBP and sagittal plane pelvic tilt and frontal plane pelvic obliquity during the SKL test as measured at baseline were investigated. Individual training and game hours were recorded, and Cox's proportional hazard models with mixed effects were used for the analysis.

RESULTS

Cox analyses revealed that sagittal plane pelvic tilt and frontal plane pelvic obliquity were not associated with LBP in floorball and basketball players during the follow-up. The hazard ratios for pelvic tilt and pelvic obliquity ranged between 0.93 and 1.08 (95% CIs between 0.91 and 1.07 and 0.83 and 1.29), respectively.

CONCLUSIONS

Pelvic movement during the SKL test is not associated with future LBP in youth floorball and basketball players.

Cricket Fast Bowling Technique and Lumbar Bone Stress Injury

INTRODUCTION

Lumbar bone stress injuries (LBSI) are the most prevalent injury in cricket. Although fast bowling technique has been implicated in the etiology of LBSI, no previous study has attempted to prospectively analyze fast bowling technique and its relationship to LBSI. The aim of this study was to explore technique differences between elite cricket fast bowlers with and without subsequent LBSI.

METHODS

Kinematic and kinetic technique parameters previously associated with LBSI were determined for 50 elite male fast bowlers. Group means were compared using independent-samples t-tests to identify differences between bowlers with and without a prospective LBSI. Significant parameters were advanced as candidate variables for a binary logistic regression analysis.

RESULTS

Of the 50 bowlers, 39 sustained a prospective LBSI. Significant differences were found between injured and noninjured bowlers in rear knee angle, rear hip angle, thoracolumbar side flexion angle, and thoracolumbar rotation angle at back foot contact; the front hip angle, pelvic tilt orientation, and lumbopelvic angle at front foot contact; and the thoracolumbar side flexion angle at ball release and the maximal front hip angle and ipsilateral pelvic drop orientation. A binary logistic model, consisting of rear hip angle at back foot contact and lumbopelvic angle at front foot contact, correctly predicted 88% of fast bowlers according to injury history and significantly increased the odds of sustaining an LBSI (odds ratio, 0.88 and 1.25, respectively).

CONCLUSIONS

Lumbopelvic motion is implicated in the etiology of LBSI in fast bowling, with inadequate lumbopelvifemoral complex control as a potential cause. This research will aid the identification of fast bowlers at risk of LBSI, as well as enhancing coaching and rehabilitation of fast bowlers from LBSI.

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.

Biomechanical risk factors of lower back pain in cricket fast bowlers using inertial measurement units: a prospective and retrospective investigation

Objectives

To investigate spinal kinematics, tibial and sacral impacts during fast bowling, among bowlers with a history of low back pain (LBP) (retrospective) and bowlers who developed LBP in the follow-up season (prospective).

Methods

35 elite male fast bowlers; senior (n=14; age=24.1±4.3 years; height=1.89±0.05 m; weight=89.2±4.6 kg) and junior (n=21; age=16.9±0.7; height=1.81±0.05; weight=73.0±9.2 kg) were recruited from professional county cricket clubs. LBP history was gathered by questionnaire and development of LBP was monitored for the follow-up season. Spinal kinematics, tibial and sacral impacts were captured using inertial measurement units placed over S1, L1, T1 and anteromedial tibia. Bonferroni corrected pairwise comparisons and effect sizes were calculated to investigate differences in retrospective and prospective LBP groups.

Results

Approximately 38% of juniors (n=8) and 57% of seniors (n=8) reported a history of LBP. No differences were evident in spinal kinematics or impacts between those with LBP history and those without for seniors and juniors. Large effect sizes suggest greater rotation during wind-up (d=1.3) and faster time-to-peak tibial impacts (d=1.5) in those with no history of LBP. One junior (5%) and four (29%) seniors developed LBP. No differences were evident in spinal kinematics or impacts between those who developed LBP and those who did not for seniors. In seniors, those who developed LBP had lower tibial impacts (d=1.3) and greater lumbar extension (d=1.9) during delivery.

Conclusion

Retrospective analysis displayed non-significant differences in kinematics and impacts. It is unclear if these are adaptive or impairments. Prospective analysis demonstrated large effect sizes for lumbar extension during bowling suggesting a target for future coaching interventions.

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.

Injury and Player Availability in Women's International Pathway Cricket from 2015 to 2019

This prospective cohort study aimed to describe injury and illness epidemiology within women's international pathway cricket, understanding what influences player availability in this unique context where players are contracted part-time. Approximately 8.4% of players were impacted by injury or illness during the year, with an average 2.3% of players completely unavailable on any given day. Most medical complaints occurred during training (111.2 injuries/100 players per year). Of all complaints, medical illness had the highest overall incidence (45.0 complaints/100 players), followed by hand injuries (24.7 injuries/100 players). Gradual onset injuries were most common. Overall average match time-loss complaint prevalence rate was 4.1% and average match time-loss injury incidence rate was 7.0 injuries/1000 days of play. Fielding (56.4 injuries/100 players per year) was the activity resulting in the highest average overall and time-loss injury incidence rates, though 'other' activities (e. g. those occurring outside of cricket participation) collectively accounted for 78.3 injuries/100 players per year. The high incidence of medical illness relative to other complaints may be a distinct feature of the women's cricket international pathway compared to other cricket samples. The high occurrence of injuries arising from 'other' activities, likely due to part-time participation, presents an opportunity for targeted injury prevention strategies.• The first study on an international women's cricket pathway, contributes to the empirical base for specific injury risks associated with the women's cricket game, which is an emerging research area for a developing sport.• Some of the findings may be a distinct feature of the women's cricket international pathway, highlighting potential opportunities for targeted prevention strategies.• With the upcoming development of an elite domestic structure these preliminary findings will provide a good starting point for physiotherapy and medical staff working in these contexts.

Performance in dynamic movement tasks and occurrence of low back pain in youth floorball and basketball players

BACKGROUND

Prospective studies investigating risk factors for low back pain (LBP) in youth athletes are limited. The aim of this prospective study was to investigate the association between hip-pelvic kinematics and vertical ground reaction force (vGRF) during landing tasks and LBP in youth floorball and basketball players.

METHODS

Three-hundred-and-eighty-three Finnish youth female and male floorball and basketball players (mean age 15.7 ± 1.8) participated and were followed up on for 3 years. At the beginning of every study year the players were tested with a single-leg vertical drop jump (SLVDJ) and a vertical drop jump (VDJ). Hip-pelvic kinematics, measured as femur-pelvic angle (FPA) during SLVDJ landing, and peak vGRF and side-to-side asymmetry of vGRF during VDJ landing were the investigated risk factors. Individual exposure time and LBP resulting in time-loss were recorded during the follow-up. Cox's proportional hazard models with mixed effects and time-varying risk factors were used for analysis.

RESULTS

We found an increase in the risk for LBP in players with decreased FPA during SLVDJ landing. There was a small increase in risk for LBP with a one-degree decrease in right leg FPA during SLVDJ landing (HR 1.09, 95% CI 1.02 to 1.17, per one-degree decrease of FPA). Our results showed no significant relationship between risk for LBP and left leg FPA (HR 1.04, 95% CI 0.97 to 1.11, per one-degree decrease of FPA), vGRF (HR 1.83, 95% CI 0.95 to 3.51) or vGRF side-to-side difference (HR 1.22, 95% CI 0.65 to 2.27) during landing tasks.

CONCLUSIONS

Our results suggest that there is an association between hip-pelvic kinematics and future LBP. However, we did not find an association between LBP and vGRF. In the future, the association between hip-pelvic kinematics and LBP occurrence should be investigated further with cohort and intervention studies to verify the results from this investigation.

LEVEL OF EVIDENCE

Prognosis, level 1b.

Injuries in England and Wales elite men's domestic cricket: A nine season review from 2010 to 2018

OBJECTIVES

This study primarily aimed to explore injury incidence rates in the three main domestic competition formats in England and Wales (First-Class, One-Day and Twenty20 [T20]). For the first time, the study also describes the epidemiology of elite men's domestic cricket injuries across nine seasons (2010-2018 inclusive).

DESIGN

Prospective cohort analysis.

METHODS

Injury incidence and prevalence from all injuries calculated according to the updated international consensus statement on injury surveillance in cricket, with statistical process control charts (SPC) used to detect trends in the data.

RESULTS

The average match injury incidence was 102 injuries/1000 days of play, with highest incidence in One-Day (254 injuries/1000 days of play), followed by T20 (136 injuries/1000 days of play) and First-Class Cricket (68 injuries/1000 days of play). Most match injuries were sustained during bowling (41.6 injuries/1000 days of play), followed by fielding (26.8 injuries/1000 days of play) and batting (22.3 injuries/1000 days of play). The thigh was the body area most commonly injured (7.4 injuries/100 players per season), with lumbar spine injuries the most prevalent (1.3% of players unavailable on any given day during the season). On average, 7.5% of players were unavailable on any given day during the domestic season when all injuries were considered (match and training). The SPC charts showed relatively consistent match injury incidence for all competitions, reproduced across all nine seasons.

CONCLUSION

These findings provide a robust empirical base for the extent of the injury problem in domestic cricket played in England and Wales, with similar injury profiles across the three formats.

Risk Factors for Lower-Extremity Injuries Among Contemporary Dance Students

OBJECTIVE

To determine whether student characteristics, lower-extremity kinematics, and strength are risk factors for sustaining lower-extremity injuries in preprofessional contemporary dancers.

DESIGN

Prospective cohort study.

SETTING

Codarts University of the Arts.

PATIENTS

Forty-five first-year students of Bachelor Dance and Bachelor Dance Teacher.

ASSESSMENT OF RISK FACTORS

At the beginning of the academic year, the injury history (only lower-extremity) and student characteristics (age, sex, educational program) were assessed using a questionnaire. Besides, lower-extremity kinematics [single-leg squat (SLS)], strength (countermovement jump) and height and weight (body mass index) were measured during a physical performance test.

MAIN OUTCOME MEASURES

Substantial lower-extremity injuries during the academic year were defined as any problems leading to moderate or severe reductions in training volume or in performance, or complete inability to participate in dance at least once during follow-up as measured with the Oslo Sports Trauma Research Center (OSTRC) Questionnaire on Health Problems. Injuries were recorded on a monthly basis using a questionnaire. Analyses on leg-level were performed using generalized estimating equations to test the associations between substantial lower-extremity injuries and potential risk factors.

RESULTS

The 1-year incidence of lower-extremity injuries was 82.2%. Of these, 51.4% was a substantial lower-extremity injury. Multivariate analyses identified that ankle dorsiflexion during the SLS (OR 1.25; 95% confidence interval, 1.03-1.52) was a risk factor for a substantial lower-extremity injury.

CONCLUSIONS

The findings indicate that contemporary dance students are at high risk for lower-extremity injuries. Therefore, the identified risk factor (ankle dorsiflexion) should be considered for prevention purposes.

Exercise-based injury prevention for community-level adolescent cricket pace bowlers: A cluster-randomised controlled trial

OBJECTIVES

To investigate if an exercise-based injury prevention program (IPP) can modify risk factors for injury in community-level adolescent cricket pace bowlers.

DESIGN

Cluster-randomised controlled trial.

METHODS

Eight cricket organisations (training two times per week and no previous involvement in a structured IPP) participated in this cluster-randomised trial. Participants were aged 14-17 years, injury free, and not currently performing a rehabilitation/exercise program. Cricket organisations (clusters) were block-randomised by computerised number generation into an intervention group (performed an eight-week IPP at training) or control group (continued their usual cricket activity). Participants were not blinded to group allocation. Strength, endurance, and neuromuscular control were assessed at baseline and follow-up. Treatment effects were estimated using linear mixed models.

RESULTS

Sixty-five male adolescent pace bowlers (intervention n=32 and control n=33) were randomised. There were significant treatment effects favouring the intervention group for shoulder strength (90°/s) 0.05 (95% CI 0.02-0.09) Nm/kg, hamstring strength (60°/s) 0.32 (95% CI 0.13-0.50) Nm/kg, hip adductor strength dominant 0.40 (95% CI 0.26-0.55) Nm/kg and non-dominant 0.33 (95% CI 0.20-0.47) Nm/kg, SEBT reach distance dominant 3.80 (95% CI 1.63-6.04) percent of leg length (%LL) and non-dominant 3.60 (95% CI 1.43-5.78) %LL, and back endurance 20.4 (95% CI 4.80-36.0) seconds. No differences were observed for shoulder strength (180°/s) (p=0.09), hamstring strength (180°/s) (p=0.07), lumbopelvic stability (p=0.90), and single leg squat knee valgus angle (dominant p=0.06, non-dominant p=0.15).

CONCLUSIONS

Exercise-based IPPs can modify risk factors for injury in community-level adolescent pace bowlers. Future research is needed to confirm if IPPs can also reduce injury risk in this population.

Joint pain and osteoarthritis in former recreational and elite cricketers

BACKGROUND

Sport participants are at increased risk of joint pain and osteoarthritis. A better understanding of factors associated with joint pain and osteoarthritis in this population could inform the development of strategies to optimise their long-term joint health. The purpose of the study was to describe the prevalence of joint pain and osteoarthritis in former cricketers, and determine whether playing position, playing standard (i.e. elite or recreational standard) and length-of-play are associated with region-specific joint pain.

METHODS

The data were from the Cricket Health and Wellbeing Study (CHWS), a cohort of 2294 current and former cricketers (played ≥1 season) in England and Wales. For this study, eligible individuals had to be aged ≥30 years and be a former cricket participant. Joint pain was defined as region-specific (hip/knee/ankle/shoulder/hand/back) pain on most days of the last month. Osteoarthritis was defined as joint-specific doctor-diagnosed osteoarthritis. Logistic regression was used to calculate unadjusted and adjusted (for history of joint injury resulting in > 4 weeks of reduced activity +/- age) odds ratios (ORs) and 95% confidence intervals (95% CIs).

RESULTS

846 individuals from the CHWS were former cricketers aged ≥30 years (3% female, aged median 62(IQR 54-69) years, 62% played cricket recreationally, median 33(IQR 21-41) cricket seasons). One-in-two (48%) reported joint pain and 38% had been diagnosed with osteoarthritis. Joint pain and OA were most common in the knee (23% pain, 22% osteoarthritis), followed by the back (14% pain, 10% osteoarthritis) and hand (12% pain, 6% osteoarthritis). After adjusting for injury, bowlers had greater odds of shoulder pain (OR (95% CI) 3.1(1.3, 7.4)) and back pain (3.6(1.8, 7.4)), and all-rounders had greater odds of knee (1.7(1.0, 2.7)) and back pain (2.1(1.0, 4.2)), compared to batters. Former elite cricketers had greater odds of hand pain (1.6(1.0, 2.5)) than former recreational cricketers. Playing standard was not related to pain at other sites, and length-of-play was not associated with joint pain in former cricketers.

CONCLUSIONS

Every second former cricketer experienced joint pain on most days of the last month, and more than one in three had been diagnosed with osteoarthritis. Compared with batters, bowlers had higher odds of shoulder and back pain and all-rounders had higher odds of back and knee pain. Elite cricket participation was only related to higher odds of hand pain compared with recreational cricket participation.

Lumbar bone mineral asymmetry in elite cricket fast bowlers

PURPOSE

Bone responds to mechanical loading by increasing bone mineral density (BMD) and/or bone area to enhance bone strength at the site of the greatest strain. Such localised adaptation has not been demonstrated at the spine. The aim of this study is to determine if BMD and/or bone mineral content (BMC) differs between dominant (ipsilateral to bowling/throwing arm) and non-dominant sides of the vertebrae in cricket fast bowlers, and whether this asymmetry differs according to stress fracture or disc injury history. A further aim was to determine if regional BMD and BMC in the lumbar spine differ between fast bowlers, other cricketers, rugby players and non-active controls, to highlight the site-specific response of lumbar vertebra to unilateral activity.

METHODS

23 fast bowlers, 14 other cricketers, 22 rugby players and 20 controls underwent an antero-posterior (AP) and lateral DXA scans of their lumbar spine to assess BMD, BMC and area. A custom analysis measured BMD and BMC of the dominant and non-dominant sides (lateral 33%) of the AP lumbar spine. BMD and BMC were compared between groups, injury status, vertebrae and sides using ANOVA.

RESULTS

Analysis of medical records showed that 6 fast bowlers had a history of lumbar stress fracture. Significantly greater BMD and BMC was found in the L4 non-dominant vertebra compared with the dominant vertebra in fast bowlers. BMD and BMC differed significantly according to vertebra, side and group, with fast bowlers having significantly greater BMD and BMC at the L3 and L4 non-dominant vertebra compared with other groups (L3: 13.3%-45.3%, L4: 15.7%-44.0%) compared with other groups. Fast bowlers who never suffered lumbar stress fracture had 3.6% and 1.7% greater BMD in the dominant and non-dominant sides of lumbar vertebrae respectively compared with those who did suffer lumbar stress fracture, but evidence of this was weaker (P = 0.08).

CONCLUSION

The lumbar spine responds to a unique unilateral high loading activity through site-specific increased bone mass at the site of most strain. Fast bowlers had increased lumbar BMD, particularly on the non-dominant side of L4, although this adaptation was less marked in those with history of lumbar stress fracture. Site-specific low bone mineral density within the lumbar side may be implicated in the aetiology of lumbar stress fracture.

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.

Injury Prevention Strategies for Adolescent Cricket Pace Bowlers

Adolescent cricket pace bowlers are prone to non-contact shoulder, low back and lower-limb injuries. Exercise-based injury prevention programmes (IPPs) are effective for reducing non-contact injuries in athletes; however, a specific programme for adolescent pace bowlers has not been published. This paper therefore seeks to provide a rationale for the development of an exercise-based IPP specific for adolescent pace bowlers. It also outlines design principles and provides an example exercise programme that can be implemented at the community level. In addition, the paper addresses other injury prevention techniques concerned with the prescription of appropriate bowling loads and the modification of poor bowling biomechanics. Performing an exercise-based IPP before cricket training could reduce injury rates in adolescent pace bowlers. Eccentric strengthening exercises can be employed to target injuries to the posterior shoulder muscles, hip adductors and hamstring muscles. The risk of low back, knee and ankle injury could also be reduced with the inclusion of dynamic neuromuscular control exercises and trunk extensor endurance exercises. Other prevention strategies that need to be considered include the modification of poor bowling biomechanics, such as shoulder counter-rotation and lateral trunk flexion. Coaches and players should also aim to quantify bowling load accurately and coaches should use this information to prescribe appropriate individualised bowling loads. Specifically, players would benefit from avoiding both long periods of low load and acute periods when load is excessively high. Future evidence is needed to determine the effectiveness of the example programme outlined in this paper. It would also be beneficial to investigate whether the modification of bowling biomechanics is achievable at the non-elite level and if bowling load can be accurately measured and manipulated within a community-level population.

Kinematic and kinetic differences between military patients with patellar tendinopathy and asymptomatic controls during single leg squats

BACKGROUND

Knee valgus alignment has been associated with lower-limb musculoskeletal injury. This case-control study aims to: assess biomechanical differences between patients with patellar tendinopathy and healthy controls.

METHODS

43 military participants (21 cases, 22 controls) were recorded using 3D-motion capture performing progressively demanding, small knee bend, single leg and single leg decline squats. Planned a priori analysis of peak: hip adduction, knee flexion, pelvic tilt, pelvic obliquity and trunk flexion was conducted using MANOVA. Kinematic and kinetic data were graphed with bootstrapped t-tests and 95% CI's normalised to the squat cycle. ANOVA and correlations in SPSS were used for exploratory analysis.

FINDINGS

On their symptomatic side cases squatted to less depth (-6.62°, p < 0.05) than controls with exploratory curve analysis revealing a pattern of increased knee valgus collapse throughout the squatting movement (p < 0.05). Greater patella tendon force was generated by: the eccentric than concentric phase of squatting (+30-43%, ES 0.52-1.32, p < 0.01), declined (plantarflexed) compared to horizontal surface (+36-51%, ES 1.19-1.68, p < 0.01) and deeper knee flexion angles (F ≥ 658.3, p < 0.01) with no difference between groups (F ≤ 1.380, p > 0.05). Cases experienced more pain on testing on decline board (ES = 0.69, p < 0.01). For symptomatic limbs pain (r_s = 0.458-0.641, p ≤ 0.05), but not VISA-P (Victoria Institute of Sport Assessment) (r_s = 0.053-0.090, p > 0.05), correlated with extensor knee moment.

INTERPRETATION

Knee valgus alignment is a plausible risk factor for patellar tendinopathy. Conclusions relating to causation are limited by the cross-sectional study design. Increasing squat depth, use of a declined surface and isolating the eccentric phase enable progression of loading prescription guided by pain.

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.

Risk Factors for Non-Contact Injury in Adolescent Cricket Pace Bowlers: A Systematic Review

BACKGROUND

Adolescent cricket pace bowlers are prone to injury. Recognising the risk factors for non-contact injury in this population will aid future injury prevention strategies.

OBJECTIVE

To identify the risk factors for non-contact injury in adolescent cricket pace bowlers.

METHODS

We systematically searched PubMed, Cochrane Library, PEDro, SPORTDiscus, Embase, and the South African Journal of Sports Medicine to identify all experimental and observational studies reporting risk factors for non-contact injuries in pace bowlers (aged 12-19 years). The search syntax included terms relevant to cricket bowling, injury, and known risk factors for injury. The Newcastle-Ottawa Quality Assessment Scale and a modified Newcastle-Ottawa Quality Assessment Scale were used to assess the risk of bias in the cohort and cross-sectional studies, respectively.

RESULTS

Sixteen studies (five cross-sectional studies, 11 cohort studies) comprising 687 participants (96% male, 75% playing cricket in Australia) met the selection criteria and were included for qualitative synthesis. Three cross-sectional studies were rated as high risk of bias and two as very high risk of bias. For the cohort studies, three were rated as low risk of bias, and eight as high risk of bias. Injury was associated with bowling biomechanics (excessive lateral trunk flexion and pelvis/hip kinematics), reduced trunk endurance, poor lumbo-pelvic-hip movement control, and early signs of lumbar bone stress. Conflicting results were found by studies examining the mixed technique, bowling workload and quadratus lumborum asymmetry.

CONCLUSIONS

The current systematic review identified a number bowling biomechanics and various neuromuscular deficiencies as risk factors for non-contact injury in adolescent pace bowlers. These factors may provide a useful target for future interventional research aiming to prevent injury in this population. Future studies should utilise prospective cohort designs, and ensure that participants are injury-free at baseline, confounding factors are well controlled and attrition rates are reported.

REGISTRATION

This systematic review was registered a priori (PROSPERO, CRD42016043956).

Elbow joint kinematics during cricket bowling using magneto-inertial sensors: A feasibility study

Magnetic and inertial measurement units (MIMUs) may provide an accessible, three-dimensional, in-field alternative to laboratory-restricted marker-based motion capture. Existing upper limb MIMU models have predominantly been validated with low-velocity motion and their suitability for use with sport-based movements remains relatively untested. We propose a MIMU system approach to enable the estimation of anatomically meaningful and participant-specific elbow kinematics with considerations for use with cricket bowling. A novel standardised elbow reference posture of 90 degrees flexion and 0 deg pronation, and functional definition of elbow joint axes of rotation calibrated the MIMU method model before it was validated across three experiments: (1) simple elbow rotations with a mechanical linkage; (2) low-velocity elbow rotations in human participants; and (3) low-medium velocity sport-based movements in human participants. The proposed MIMU method demonstrated high elbow kinematic measurement agreement when compared with a criterion measure across all three conditions. However, during experiment 3, sensor components neared their measurement capacity and the MIMU method elbow flexion measurement variability increased. We conclude that the proposed MIMU method can estimate anatomically referenced, participant-specific joint angles, however, the hardware specifications of currently available systems may limit application in high-velocity/acceleration situations, preventing the measurement of cricket bowling in-field for now.

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.

Single leg squat ratings by clinicians are reliable and predict excessive hip internal rotation moment

BACKGROUND

Single leg squats are commonly used subjective assessments of general biomechanical function, injury risk, as a predictor for recovery and as an outcome measure of rehabilitation. While 3D motion capture is a useful tool for elite sports performance and research it is impractical for routine clinical use.

RESEARCH QUESTION

This cross-sectional study aims to: assess reliability and validity of clinicians' subjective ratings of single leg squats compared to 3D motion capture, and to identify whether performance predicts joint moments.

METHODS

22 healthy military volunteers were simultaneously recorded on video and 3D motion capture performing single leg squats. Videos were reviewed twice by 5 physiotherapists rating performance on a 0-5 scale assessing squat depth, hip adduction, pelvic obliquity, pelvic tilt and trunk flexion summated into a composite score.

RESULTS

Hip adduction and trunk flexion exhibited moderate to substantial inter- and intra-rater reliability (range κ = 0.408-0.699) other individual criteria were mostly fair (κ ≤ 0.4). Composite scores for inter-rater reliability were ICC_(1,1) = 0.419 and ICC_(1,κ) = 0.783 and intra-rater reliability were ICC_(1,1) = 0.672 and κ(w) = 0.526. Validity against 3D kinematics was poor with only 6/75 individually rated criteria reaching κ > 0.40. Correlation was found between composite scores and hip internal rotation moment (r_s = 0.571, p = 0.009).

SIGNIFICANCE

Repeated use of single leg squats by a single practitioner is supported. Comparisons between clinicians are unreliable but improved by average measures from multiple raters. Heterogeneous reliability across scoring components suggests a qualitative description of the criteria scored is less ambiguous than using composite scores in a clinical setting. Composite scores may be more useful for analysis at a population level. Poor validity against kinematic data suggests clinicians use additional information upon which they find agreement such as estimating kinetics. Correlation between hip internal rotation moment and subjective ratings may be such an example of clinicians trying to identify excessive abnormal loading.

Ankle restrictive firefighting boots alter the lumbar biomechanics during landing tasks

Firefighters incur high incidences of lower back and body injuries. Firefighting boots, with specific design requirements, have been shown to reduce ankle range of motion. This reduction has been associated with impaired force dissipation and lower body kinematic alterations. Thus, the aim of this study was to determine the relationship between firefighting boots, lumbar biomechanics and load carriage during landing. Our data indicates that when wearing firefighting boots, lumbar forces increased and kinematics changed in frontal and transverse planes. These changes may be occurring due to the restrictive shaft of the firefighting boot reducing ankle range of motion. Comparisons between unloaded and loaded conditions also showed increased changes in lumbar biomechanics, independent of footwear worn. Therefore, wearing firefighting boots, in addition to operational loading, may be placing firefighters at greater risk of lumbar injuries. Future research investigating firefighting boots and additional load carriage on lower body biomechanics during landing is recommended.

Injuries in Cricket

Context:

Cricket is a popular global sport that requires a combination of physical fitness, skill, and strategy. Although a noncontact sport, overuse and impact injuries are common since players engage in a wide range of physical activities, including running, throwing, batting, bowling, catching, and diving. Significant or match time-loss injuries are defined as those that either prevent a player from being fully available for selection in a major match, or during a major match, cause a player to be unable to bat, bowl, or keep wicket when required by either the rules or the team’s captain. This review describes the various region-wise injuries sustained in cricket along with their epidemiology, biomechanics, treatment, and prevention.

Evidence Acquisition:

Data were collected from peer-reviewed articles (obtained via PubMed search) published through November 2016 that involved the medical, biomechanical, and epidemiological aspects of cricket injuries.

Study Design:

Clinical review.

Level of Evidence:

Level 4.

Results:

Cricket was one of the first sports to publish recommended methods for injury surveillance in 2005 from England, South Africa, Australia, the West Indies, and India. While the incidence of injuries is about the same, the prevalence of injuries has increased due to game format changes, increasing number of matches played, and decreased rest between matches. Bowling (41.3%), fielding, and wicket keeping (28.6%) account for most injuries. Acute injuries are most common (64%-76%), followed by acute-on-chronic (16%-22.8%) and chronic ones (8%-22%). The most common modern-day cricket injury is hamstring strain, and the most severe is lumbar stress fracture in young fast bowlers.

Conclusion:

With improved understanding of the scientific and medical aspects of cricket, along with advances in surgical and nonsurgical treatment techniques, the time to return to play has shortened considerably. While the prevalence of cricket injuries has increased, their severity has decreased over the past decades.

Medical Attention Injuries in Cricket: A Systematic Review of Case Reports

BACKGROUND

Cricket, classified as noncontact game, has been shown to be associated with increased incidence of injury. Further the recent consensus update in cricket injury surveillance have updated the injury definitions which includes "Medical Attention" injuries. The purpose of this review was to systematically review the various case reports and studies reporting injuries in the game of cricket that fall under the gambit of medical attention injuries.

MATERIALS AND METHODS

A systematic review was conducted online using PubMed and Google Scholar, as per Preferred Reporting Items for Systematic reviews and Metaanalyses guidelines. Predefined eligibility criteria were applied, and the data thus compiled were analysed.

RESULTS

A total of 32 studies reporting 43 players including 42 males and 1 female were included in the review. Bowling injuries were the most commonly reported injury. Impact injury was the most common mode with acute presentation in batting and fielding injury, whereas it was gradual onset mode with chronic presentation in bowling injuries. Head and neck injuries were the most common in batting injuries while extremity injuries were common in fielding and bowling injuries. No injuries were reported in umpires.

CONCLUSION

The evidence provided, although not sufficient for any recommendation, it should alert the physicians and those concerned with the primary care of the cricketers to be vigilant of the eccentricity and severity of the injuries, their atypical presentation, mode, mechanism and trend, thereby being prepared for the unexpected presentations.

Lumbopelvic muscle activation patterns in adolescent fast bowlers

INTRODUCTION

Adolescent fast bowlers are prone to sustaining lumbar injuries. Numerous components have been identified as contributing factors; however, there is limited empirical evidence outlining how the muscles of the lumbopelvic region, which play a vital role in stabilising the spine, function during the bowling action and the influence of such activation on injuries in the fast bowler.

METHODS

Surface electromyography was utilised to measure the function of the lumbar erector spinae, lumbar multifidus, gluteus medius and gluteus maximus muscles bilaterally during the fast bowling action in a group of 35 cricket fast bowlers aged 12-16 years.

RESULTS

Two prominent periods of activation occurred in each of the muscles examined. The period of greatest mean activation in the erector spinae and multifidus occurred near back foot contact (BFC) and within the post-ball-release (BR) phase. The period of greatest mean activation for the gluteus medius and gluteus maximus occurred during phases of ipsilateral foot contact.

DISCUSSION

The greatest periods of muscle activation in the paraspinal and gluteal muscles occurred at times where vertical forces were high such as BFC, and in the phases near BR where substantial shear forces are present.

CONCLUSION

The posterior muscles within the lumbopelvic region appear to play a prominent role during the bowling action, specifically when compressive and shear forces are high. Further research is required to substantiate these findings and establish the role of the lumbopelvic muscles in the aetiology of lumbar injury in the cricket fast bowler.