Utility of triaxial accelerometry in the detection of neuromuscular fatigue and vertical stiffness in elite netball

Abstract

A recent proliferation in research and application of wearable tracking devices in high performance sporting environments has seen a resultant increase in the depth of information which can be derived via this technology. Research has been suggested that changes in accelerometer-derived within-match loading may be indicative of neuromuscular fatigue (NMF) caused by the development of movement inefficiencies. The cause of these inefficiencies has yet to be identified, although, speculated to be influenced by vertical stiffness (Kvert), calculation of which has also been suggested to be achievable via accelerometer-derived data. The aim of the first experimental chapter was to establish the measurement accuracy of accelerometry to determine Kvert, during running, hopping and jumping tasks, which influenced the subsequent implementation within the second experimental chapter. Moderate validity was observed between accelerometer and the criterion measure during running tasks, although, reliability was questionable. The aim of the second experimental chapter was to establish an association between accelerometer-derived match load changes and NMF; determined through the implementation of pre- and post-match isometric mid-thigh pull (IMTP). Additionally, to determine whether Kvert plays a role in these match load changes and therefore, establish an association with NMF. Results of the IMTP suggests there is a likely small decrease in peak vertical force as a result of netball match play, while a likely small increase was observed in both Kvert and vector magnitude (VM) during the shuttle run. Within-match load changes were observed between the first and alternative quarters, particularly within shooting and midcourt positions. Within-subject correlations found that total match VM/min is not related to the extent of NMF observed but the change in VM/min between the first and last quarter was found to be associated with both peak vertical force and Kvert, although, no association was found between changes in Kvert when compared to neuromuscular parameters (peak vertical force, RFD). NMF is currently monitored through post-match testing procedures, only providing information on the presence and extent of this variable after the completion of a match. The ability to identify the development of NMF or movement inefficiencies through changes in loading may allow practitioners to develop a method of deriving 'real-time' information relevant to these variables. This information could influence rotation policy or substitution strategy as a means of reducing the negative effects of this occurrence, such as injury.

Date of Award	2017
Original language	English