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Abstract
This thesis describes the development of a protocol to analyse the tackle in rugby union. The tackle is a collision event between a Ball-carrier and one or more opponents. The most frequently occurring match event, it has been consistently associated with a high risk of injury. Quantitative investigations of skill and injury in the tackle are hampered by its multi-factorial nature. A reliable quantitative protocol, prepared through a systematic and repeatable framework, represents a potential method of collecting information to narrow the focus for future investigation.
A qualitative analysis protocol was developed to assess the tackle through evaluation of 107 mostly nominal fields. Fields were developed in consultation with epidemiological data, coaching literature, and applying biomechanical and qualitative skill analysis frameworks to identify aspects of skill and injury. The reliability of the analysis protocol was then assessed in two inter-rater reliability (IRR) studies. The results of the first IRR study were reviewed at a meeting of an expert panel and the protocol was modified to improve agreement before being tested in a second IRR study.
In the first IRR study, substantial agreement (>70%) was obtained in 24 fields. Agreement amongst participants for medical events was almost perfect (91%) and agreement identifying a tackle according to the study definition was 74%. The mean agreement in all fields was moderate (61%). Slight agreement was observed for identifying the body region struck and the direction of travel of the players following the impact. The timing of analysis was identified as a potential reason for poor agreement. The results of the second IRR study suggested that providing a specific temporal reference for observations improved agreement in some fields and substantial agreement was observed in 48 fields. There was still disagreement in some important fields of the protocol. Following operational modifications, the protocol was used to code 6,618 tackles in a larger study of tackling technique and injury risk. A sample analysis of 100 tackles is presented to demonstrate the utility of the protocol.
Few qualitative technique analyses have described the development of the analysis method or examined IRR following changes to improve agreement. The results of this research indicate that the general agreement between raters using this protocol was moderate, and care needs to be taken in defining the variables used.