Epidemiological studies undertaken in Australia, South Africa, England and the West Indies have repeatedly demonstrated that fast bowlers have the highest risk of injury in cricket with the lower back being most susceptible to both traumatic and overuse injuries (Glazier, 2010).

INJURY RISK FACTORS IN CRICKET

The high prevalence of injury amongst cricket fast bowlers exposes both extrinsic (environment-related) and intrinsic (person-related) risk factors that contribute to non-contact injury. Identifying and defining the relative importance of these risk factors is necessary in order to optimise injury prevention efforts.

The following factors were found to be associated with injury:

• bowling shoulder internal rotation strength deficit
• compromised dynamic balance
• lumbar proprioception
• bowling workload.

Bowling Workload was the only extrinsic factor associated with injury in cricket fast bowlers. A high bowling workload (particularly if it represented a sudden upgrade from a lower workload) increased the subsequent risk to sustaining an injury (Hecimovich, Stomski & Norman, 2016).

Technique-related factors associated with injury include:

• shoulder-pelvis flexion-extension angle
• shoulder counter-rotation
• knee angle
• proportion of side-flexion during bowling

BIOMECHANICS OF FAST BOWLING AND LBP

Research has shown that Off-break delivery results in significantly higher trunk alignment, shoulder counter-rotation, trunk contralateral flexion and ‘crunch factor’ when compared with other delivery variations. The ‘crunch factor’ is defined as the instantaneous product of lateral flexion and axial rotational velocity of the lumbar spine.

Based on recent research, it is argued that the crunch factor could be important in cricket fast bowling especially considering that peak crunch factor appears to occur just after front foot impact when ground reaction forces are known to be at their highest. The combination of counter shoulder rotation and contralateral flexion at speed increases torsion on the lower back joints and musculature (Glazier, 2010).

Interestingly and in contrast to other sports , symmetry of the trunk musculature in cricket fast bowlers has been associated with increased incidence of low back pain.Functional asymmetrical properties have been seen prevalently in rotation based sports. In cricket this asymmetry includes greater thickness of obliquus internus abdominis on the non-dominant side. Development of asymmetry of abdominal muscle thickness in fast bowlers is explained by the asymmetrical biomechanics of fast bowling (Gray, Aginsky, Derman, Vaughan, Hodges, 2016).

LOW BACK PAIN ASSESSMENT

Screening for injury risk factors associated with increased lumbar spine loading is an important consideration for early identification of risk and prevention of injury in cricket. Shoulder internal rotation, hip rotation and dynamic balance have been associated with low back pain incidence in cricket (Hecimovich, Stomski & Norman, 2016).

Musculoskeletal pain develops when movements and alignments are repeated in the same direction over repetitive activities. Repeated movements of the lumbar region have the potential to increase the flexibility of lumbar segments in a specific direction. This increase in flexibility is proposed to reinforce the use of direction-specific movement  patterns that subsequently become generalised across many activities. The exposure of spinal tissues to repeated low-magnitude loading in the same direction is proposed to contribute to the accumulation of excessive tissue stress, microtrauma, and eventually LBP. Lumbar flexion, lumbar extension, lumbar rotation, lumbar rotation with flexion, and lumbar rotation with extension are typically used to screen movement patterns associated with LBP.

MONITORING INJURY RISK IN CRICKET

Injury manifestation is multi-faceted.  Monitoring practices that incorporate biomechanical, workload and psychological factors tracked over time can aid coaches in identifying and understanding individual-specific risk factors.

Specific examples include:

• Workload and changes in workload, specifically number of balls bowled;
• Pain and soreness ratings in lower back, shoulder, hips and lower limb;
• Factors that increase spine loading during cricket fast bowling such as shoulder internal rotation, hip internal rotation and dynamic balance.

Regular monitoring of these factors can guide decision making around training load management and S&C interventions.