Movement variability within the kinetic and kinematic variables associated with male fast cricket bowlers’ techniques that influence lumbar spine injury.

Abstract

Cricket fast bowling is a skill that is susceptible to the development of overuse related injury, predominantly a stress fracture to the lumbar spine. Movement variability is a developing area within biomechanics and has been related to overuse injury, though more knowledge is needed to improve the understanding of this concept. The aim of this study was to investigate the differences in movement variability within the kinetic and kinematic variables reported to significantly increase the risk of lumbar back injury. Two male university cricketers (mean ± S.D.: age 23 ± 2 years; stature 1.82 ± 0.03 m; body mass 83.5 ± 6.5 kg) performed twelve deliveries at match intensity within which their technique was captured using CODAmotion (200 Hz), a Kistler force platform (1000 Hz) and a high definition video camera (50 Hz). Seventeen active CODA markers were located on body landmarks to quantify motion data through the delivery stride. Both participants were classified as mixed action bowlers. Pearsons’ product-moment correlation coefficients (r) showed that participant 1 (r = 0.882, P < 0.01) and 2 (r = 0.688, P< 0.05) showed a larger shoulder angle at back foot contact significantly correlated with increased shoulder counterrotation through the delivery stride. Therefore, it would be advantageous to adopt a more side-on shoulder alignment in order to reduce risk of injury. The contralateral side-flexion angle for participant 1 (29.5 ± 1.0°) and 2 (25.8 ± 0.6°) showed minimal variability that suggested control in the movement in which greater variation occurred prior to and at the point of peak contralateral side-flexion, a positive trait previously hypothesised to reduce variability-overuse injury. Further knowledge is needed to ascertain whether movement variability has a significant effect on injury mechanisms and also to establish if variability is the cause or effect of injury.