Elite football players are required to train multiple metabolic and physical parameters simultaneously. Due to the nature of the competition schedule and training time available players often perform sports-specific endurance-training and high-load, low repetition resistance-training on the same day (Hoff et al., 2006). Empirical evidence highlights that when two disparate forms of muscular contraction are trained within the same training cycle, adaptations in strength and power related variables can become blunted - a situation most commonly referred to as the ?interference phenomenon? (Hickson, 1980). Experimental data suggest the organisation of each training stimulus can modulate the training response and exacerbate the ?interference phenomenon?. However at present few data exist concerning how elite football teams currently organise their concurrent-training programmes. Furthermore to the authors? knowledge no practical guidelines exist as to minimise the interference phenomenon within the constraints of the applied football environment. Therefore, the aim of this thesis was to investigate the impact of training organisation on the acute and chronic responses to football-specific concurrent exercise programmes in elite football players. Initially we conducted a pilot study (chapter 3) to observe the concurrent-training strategies currently in place at a professional football club. The study had two aims (1) to describe the training frequency and training load across the first 10 weeks of a competitive season and (2) to characterise the acute organisation of training and nutritional intake around concurrent-training. It was found that training frequency and volume was greatest during the initial three weeks of the observation. Following this training frequency and training load decreased significantly. Although, following the decrease in training load there were no between week fluctuations in training load. Together, these results suggested that the reduced ?pre-season period? (i.e. 3 weeks) and the lack of fluctuation in training volume and intensity from weeks 4 to 10 may not be optimal for longer-term muscle performance (Fleck, 1999). The secondary findings from this study demonstrated that when concurrent-training was performed on the same day, the order of aerobic and resistance exercise, the nutritional availability and the recovery period between training sessions was unsystematic. It was thought that this approach to the organisation of concurrent-training may not have been optimal for longer term muscle adaptation. Collectively, this study showed that despite large investment in sports science departments and highly experienced coaches, the application of periodised and well-structured training is not always possible. The lack of systematic training and nutritional intake observed at this football club could have exacerbated the ?interference phenomenon? and subsequently been sub-optimal for longer term muscle adaptation and athlete performance. The purpose of study 1 and 2 (chapters 5 6) was to investigate if the concurrent exercise protocols previously observed could modulate the ?interference phenomenon?. In a series of studies we investigated the muscular adaptations following 5 weeks of strength-training performed either before or after football-specific endurance-training (?S + E? and ?E + S?). It was found that improvements in strength and power related variables become blunted in the S + E training group. It was hypothesised that the between group differences could be explained by the differences in muscle architecture adaptation observed in the E + S training group. As both training groups completed similar training loads it was thought that the recovery period and nutrient timing associated with each training group could have either ?enhanced? or ?blunted? underlying adaptive mechanisms respectively. Although the underpinning molecular or metabolic process responsible for the between group differences in architectural adaptation could not be concluded from this study. Study 3 investigated the hormonal responses to two concurrent-training and nutritional scenarios previously observed at a professional football club. This investigation demonstrated that the sequence of concurrent-training, the recovery period between exercise bouts and the nutritional support provided before, between and after training could influence acute exercise induced hormonal secretion. Whilst the hormonal hypothesis for increasing muscle hypertrophy is questionable (West et al., 2009) the present data in combination with the previous training study suggest that exercise induced hormonal secretion may be involved in other metabolic processes which influence the geometry of the fascicule (i.e. muscle architecture). This thesis has highlighted the need for research to investigate the effect of concurrent-training the applied exercise setting. The lack of studies to investigate the effects of concurrent-training in elite football players has limited our understanding of the physiological effects of concurrent-training in elite football players. Whilst this thesis highlighted that the organisation of the training and nutrition can influence the interference phenomenon, more work is required to confirm these findings. Specifically, our understanding of the effect of manipulating acute training variables on the physiological mechanisms responsible for the effectiveness of concurrent-training programmes require further study. The incorporation of a range of scientific techniques in a controlled setting could lead to a theoretical framework for understanding how to plan and deliver concurrent-training programmes in the applied setting so that the interference phenomenon is minimised.
|Publication status||Published - 2014|