The relevance of potential indicators of external load for movement evaluation in elite football training

Football is an intermittent (Bangsbo, 1994; Shephard, 1999; Reilly, 2005) and non-linear team sport. Coaches and practitioners must, therefore, prepare players to complete relatively large volumes of multidirectional activity that are short in duration due to frequent changes. One key aspect of ensuring the appropriateness of any training strategy is to develop and implement an effective training load monitoring strategy. Global Positioning Systems (GPS) incorporated into Micro-Electro-Mechanical Systems (MEMS) devices appear to be the technology that has been most widely adopted to determine activity (Akenhead & Nassis, 2016). The commonly used GPS technologies are regularly accompanied with tri-axial accelerometer within the MEMS hardware. It may be hypothesised that the progression of multiplanar MEMS accelerometer technologies may allow the frequent change of directions and velocities to be more accurately measured and, therefore, evaluate elite football training more effectively. There is, however, currently a lack of applied research, which has attempted to establish the utility of MEMS accelerometers to appropriately capture the movement requirements associated with elite football training. The overall aim of the research contained within the present thesis was, therefore, to investigate the relevance of indicators of external load for the evaluation of the movement requirements in elite football. Study one (chapter three), therefore, attempted to evaluate if current external training load monitoring methods in Premier League football effectively differentiate between different coaching methods. The training load patterns observed between different Premier League coaching groups within an inseason week were very similar. Differences were, however, present between the volume of TD, PL and TRIMP observed between the coaching groups. There was, however, little difference between the values of m.min-1 observed between three of the four coaching groups. The observed training load patterns between the four coaching groups appear to suggest that the elite football training loads observed were largely modulated via duration. These findings suggest that the training load monitoring methods widely used within elite football may be ineffective in capturing the true differences in coaching methods, especially with reference to movement requirements. Study two (chapter four) aimed to evaluate the effectiveness of MEMS accelerometers to describe differences in movement requirements between a range of football training activities. The PL and PL.m-1 associated with different football training activities were compared. PL did not clearly distinguish between the movement requirements associated with the training activity. PL.m-1 , however, was found to be an effective external training load measure for describing differences in movement requirements between different training activities. Study three (chapter five) then endeavoured to examine the sensitivity of MEMS accelerometer, GPS, heart rate and perceptually derived variables to changes in movement requirements in football specific activities. The systematic manipulation of movement requirements was completed via changing relative pitch dimensions in commonly completed training activities. The findings suggest that PL.m-1 may effectively distinguish between changes in movement requirements modulated by relative pitch dimension. The measure was found to be greater when pitch dimensions were smaller, suggesting the variables may be sensitive to increases in multidirectional activity. M.min-1 also demonstrated sensitivity between movement requirements, however, conversely to PL.m-1 , the variable appeared to capture the greater locomotive activity associated with larger pitch dimensions. The other accelerometer, internal and perceptual based variables did not demonstrate the sufficient sensitivity to distinguish between the movement requirements associated with changes in relative pitch dimensions. In summary, the findings and the relevant review the literature (chapter two), enable a conceptual monitoring model in football to be proposed. It appears that the volume component of training may typically be duplicated across traditional monitoring models and instead only one variable that captures this value should be used. Intensity is proposed as the second key component of the model. Due to the large variation in physiological response to intensity of different training modalities, it appears suitable to include both a locomotive and change of direction based measure for the component of training load. The final piece of the conceptual model includes a measure, which captures the movement requirement of the activity and, therefore, may inform the type of training load. PL.m-1 ’s demonstrated utility now leads the researchers to propose the variable may suitably achieve this goal. The components of this conceptual model must, however, be challenged and further researched in the future. Beyond the research outcomes from the current thesis, several professional development aims were also presented. It was hoped that the researcher’s research, related dissemination and networking, and management and leadership skills would all be developed. Throughout the thesis, these key themes of professional development are revisited throughout. It is suggested that these skills have all been significantly developed throughout the professional doctorate course. Evidence for this development is present within the investigations conducted in chapters three, four and five, the dissemination outlined in chapter six and throughout the reflective pauses. It is, however, suggested that there is certainly further room for improvement in each of these areas.