Date of Award

2018

Degree Type

Thesis

Degree Name

Doctor of Philosophy

School

School of Medical and Health Sciences

First Advisor

Associate Professor Sophia Nimphius

Second Advisor

Dr Robert Lockie

Abstract

The goal of fast bowling in cricket is to dismiss a batsman for as few runs as possible. To assist this goal, fast bowlers will attempt to maximise ball release velocity (BRV) to decrease the decision-making and stroke execution time of the opposing batsmen. Fast bowlers will also employ various delivery lengths (i.e. short, good and full) to assist in affecting a batsman’s stroke execution.

Several issues remain to be addressed with regards to the biomechanical assessment of fast bowling. This is particularly evident when analysing fast bowling performance (i.e. BRV), the implications of front foot loading (i.e. vertical and braking ground reaction forces [GRFs]) and the associated kinematics (i.e. knee, shoulder, and trunk angles). The biomechanics of delivery lengths, spell demands, periodised strength training interventions, and the potential to conduct biomechanical analyses during match-play, have received limited attention within the scientific literature with respect to fast bowling. Therefore, the purpose of this thesis was fourfold:

1) determine if changes in delivery length necessitate acute alterations in fast bowling biomechanics and BRV;

2) identify whether an extended eight-over bowling spell resulted in changes in biomechanics or performance within different delivery lengths;

3) assess the chronic effects of a periodised strength training intervention upon front foot loading and performance in fast bowlers; and

4) investigate the reliability and validity of inertial measure unit (IMU) derived trunk and tibia accelerations with respect to GRF during front foot contact (FFC). This series of studies provides valuable information about the implications of delivery length, spell demands and the influence of strength training upon fast bowling biomechanics and performance, as well as the first investigation on the reliability and validity of segmental load measures in comparison to FFC GRF for fast bowlers.

Study 1 outlined that changes in delivery length did not necessitate alterations in fast bowling biomechanics or BRV. Therefore, it appeared that fast bowlers were able to employ different delivery lengths without significant changes in their technique, which is ultimately beneficial to the goal of fast bowling. Study 2 demonstrated that an extended eight-over bowling spell did not result in any biomechanical or performance differences when comparing the average of the first and last three overs. Fast bowlers were able to maintain their technique and FFC loading patterns during a single extended bowling spell, which provided support to current bowling workload monitoring practices. Study 3 demonstrated that an eight-week periodised strength training program can elicit significant improvements in strength and lower-limb eccentric capacity among fast bowlers. However, this had minimal impact upon FFC GRFs, with no significant changes in BRV between pre- and post-testing. These findings may indicate that a combined approach of strength and skill training is necessary for improvements in BRV. Study 4 documented that IMU derived trunk and tibia segment accelerations were reliable, but not a valid representation of GRF during FFC. With further investigation, segment acceleration could be a useful measure for fast bowling performance and biomechanics, but does not provide an appropriate representation of GRF during FFC.

Access Note

The fulltext of Chapters 2, 3, 4, 5, and 6 are not included in this version of the thesis.

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