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 .

Variability of PlayerLoad, Bowling Velocity, and Performance Execution in Fast Bowlers Across Repeated Bowling Spells.

PURPOSE: The use of wearable microtechnology to monitor the external load of fast bowling is challenged by the inherent variability of bowling techniques between bowlers. This study assessed the between-bowlers variability in PlayerLoad, bowling velocity, and performance execution across repeated bowling spells. METHODS: Seven national-level fast bowlers completed two 6-over bowling spells at a batter during a competitive training session. Key dependent variables were PlayerLoad calculated with a MinimaxX microtechnology unit, ball velocity, and bowling execution based on a predetermined bowling strategy for each ball bowled. The between-bowlers coefficient of variation (CV), repeated-measures ANOVA, and smallest worthwhile change were calculated over the 2 repeated 6-over bowling spells and explored across 12-over, 6-over, and 3-over bowling segments. RESULTS: From the sum of 6 consecutive balls, the between-bowlers CV for relative peak PlayerLoad was 1.2% over the 12-over bowling spell (P = .15). During this 12-over period, bowling-execution (P = .43) scores and ball-velocity (P = .31) CVs were calculated as 46.0% and 0.4%, respectively. CONCLUSIONS: PlayerLoad was found to be stable across the repeated bowling spells in the fast-bowling cohort. Measures of variability and change across the repeated bowling spells were consistent with the performance measure of ball velocity. The stability of PlayerLoad improved when assessed relative to the individual's peak PlayerLoad. Only bowling-execution measures were found to have high variability across the repeated bowling spells. Player- Load provides a stable measure of external workload between fast bowlers.

The validity of microsensors to automatically detect bowling events and counts in cricket fast bowlers.

PURPOSE: Bowling workload is linked to injury risk in cricket fast bowlers. This study investigated the validity of microtechnology in the automated detection of bowling counts and events, including run-up distance and velocity, in cricket fast bowlers. METHOD: Twelve highly skilled fast bowlers (mean ± SD age 23.5 ± 3.7 y) performed a series of bowling, throwing, and fielding activities in an outdoor environment during training and competition while wearing a microtechnology unit (MinimaxX). Sensitivity and specificity of a bowling-detection algorithm were determined by comparing the outputs from the device with manually recorded bowling counts. Run-up distance and run-up velocity were measured and compared with microtechnology outputs. RESULTS: No significant differences were observed between direct measures of bowling and nonbowling events and true positive and true negative events recorded by the MinimaxX unit (P = .34, r = .99). The bowling-detection algorithm was shown to be sensitive in both training (99.0%) and competition (99.5%). Specificity was 98.1% during training and 74.0% during competition. Run-up distance was accurately recorded by the unit, with a percentage bias of 0.8% (r = .90). The final 10-m (-8.9%, r = .88) and 5-m (-7.3%, r = .90) run-up velocities were less accurate. CONCLUSIONS: The bowling-detection algorithm from the MinimaxX device is sensitive to detect bowling counts in both cricket training and competition. Although specificity is high during training, the number of false positive events increased during competition. Additional bowling workload measures require further development.

Training and competition workloads and fatigue responses of elite junior cricket players.

PURPOSE: This study investigated key fatigue and workload variables of cricket fast bowlers and nonfast bowlers during a 7-wk physical-preparation period and 10-d intensified competition period. METHODS: Twenty-six elite junior cricketers (mean ± SD age 17.7 ± 1.1 y) were classified as fast bowlers (n = 9) or nonfast bowlers (n = 17). Individual workloads were measured via global positioning system technology, and neuromuscular function (countermovement jump [relative power and flight time]), endocrine (salivary testosterone and cortisol concentrations), and perceptual well-being (soreness, mood, stress, sleep quality, and fatigue) markers were recorded. RESULTS: Fast bowlers performed greater competition total distance (median [interquartile range] 7049 [3962] m vs 5062 [3694] m), including greater distances at low and high speeds, and more accelerations (40 [32] vs 19 [21]) and had a higher player load (912 [481] arbitrary units vs 697 [424] arbitrary units) than nonfast bowlers. Cortisol concentrations were higher in the physical-preparation (mean ± 90% confidence intervals, % likelihood; d = -0.88 ± 0.39, 100%) and competition phases (d = -0.39 ± 0.30, 85%), and testosterone concentrations, lower (d = 0.56 ± 0.29, 98%), in the competition phase in fast bowlers. Perceptual well-being was poorer in nonfast bowlers during competition only (d = 0.36 ± 0.22, 88%). Differences in neuromuscular function between groups were unclear during physical preparation and competition. CONCLUSIONS: These findings demonstrate differences in the physical demands of cricket fast bowlers and nonfast bowlers and suggest that these external workloads differentially affect the neuromuscular, endocrine, and perceptual fatigue responses of these players.

Throwing workload and injury risk in elite cricketers.

OBJECTIVE: To investigate the risk between throwing workload and upper limb injury in elite cricketers. DESIGN: Prospective cohort study. SETTING: Elite Australian cricket. PARTICIPANTS: 28 adult male cricketers aged 18-32 years. ASSESSMENT OF RISK FACTORS: Daily throwing workload and injury were prospectively monitored over the 2007-2008 cricket season. Risk ratios (RRs) were calculated to describe the association between throwing workload and injury. MAIN OUTCOME MEASUREMENT: Upper limb injury associated with throwing. RESULTS: Seven (25%) players sustained an injury during the season. Injured players threw approximately 40 more throws/week (p=0.004) and 12.5 more throws per throwing day (p=0.061) than uninjured players. Players were at a significantly increased risk of injury if they completed more than 75 throws/week (RR=1.73, 95% CI=1.03 to 2.92), and there was a trend towards an increased risk if they completed more than 40 throws per throwing day (RR=1.41, 95% CI=0.88 to 2.26). Injured players also completed more throws and had more throwing days (and consequently less rest days) in the week before injury, as compared with the rest of their season preceding that point. CONCLUSION: An increased throwing workload is a risk factor for the development of upper limb injury in elite cricketers. Investigation of the kinematics of throwing in elite cricketers would complement this study, and further research is required to develop detailed throwing workload guidelines for cricketers across a range of ages.

Pace bowlers in cricket with history of lumbar stress fracture have increased risk of lower limb muscle strains, particularly calf strains.

OBJECTIVE: To assess whether a history of lumbar stress fracture in pace bowlers in cricket is a risk factor for lower limb muscle strains. METHODS: This was a prospective cohort risk factor study, conducted using injury data from contracted first class pace bowlers in Australia during seasons 1998-1999 to 2008-2009 inclusive. There were 205 pace bowlers, 33 of whom suffered a lumbar stress fracture when playing first class cricket. Risk ratios ([RR] with 95% confidence intervals[CI]) were calculated to compare the seasonal incidence of various injuries between bowlers with a prior history of lumbar stress fracture and those with no history of lumbar stress fracture. RESULTS: Risk of calf strain was strongly associated with prior lumbar stress fracture injury history (RR = 4.1; 95% CI: 2.4-7.1). Risks of both hamstring strain (RR = 1.5; 95% CI: 1.03-2.1) and quadriceps strain (RR = 2.0; 95% CI: 1.1-3.5) were somewhat associated with history of lumbar stress fracture. Risk of groin strain was not associated with history of lumbar stress fracture (RR = 0.7; 95% CI: 0.4-1.1). Other injuries showed little association with prior lumbar stress fracture, although knee cartilage injuries were more likely in the non-stress fracture group. CONCLUSION: Bony hypertrophy associated with lumbar stress fracture healing may lead to subsequent lumbar nerve root impingement, making lower limb muscle strains more likely to occur. Confounders may be responsible for some of the findings. In particular, bowling speed is likely to be independently correlated with risk of lumbar stress fracture and risk of muscle strain. However, as the relationship between lumbar stress fracture history and calf strain was very strong, and that there is a strong theoretical basis for the connection, it is likely that this is a true association.

The reliability of musculoskeletal screening tests used in cricket.

OBJECTIVES: To determine the inter- and intra-observer reliability of a field-based musculoskeletal screening protocol used to measure potential injury risk factors in cricket fast bowlers. DESIGN: Test-retest reliability study. SETTING: High performance Australian cricket. PARTICIPANTS: Ten volunteers. Two sports physiotherapists conducted the testing. MAIN OUTCOME MEASURES: Participants completed the following tests: knee extension; modified Thomas test (hip extension and abduction); hip internal and external rotation; combined elevation; ankle dorsiflexion lunge; bridging hold; prone four point hold; and calf heel raises. METHODS: For each of the tests, the participants were tested by each physiotherapist twice, and the inter- and intra-observer reliability were concurrently assessed. RESULTS: The inter-observer reliability of the tests was generally poor, with only four of the ten tests having an intraclass correlation coefficient (ICC) greater than 0.80 (range of ICCs 0.27-0.99). The intra-observer reliability of the tests was considerably higher, with nine tests having an ICC greater than 0.80 (range of ICCs 0.56-0.99). CONCLUSIONS: With the exception of the bridging hold, all tests would be considered acceptable where only one observer was conducting the testing. However, only the ankle dorsiflexion lunge, combined elevation test, calf heel raise test and prone four point hold have acceptable reliability when there are multiple physiotherapists recording measurements.