The effects of training organisation on the physiological, metabolic and molecular responses to a soccer-specified laboratory based training simulation

Player's performance in competitive matches is partly determined by the systematic training programmes that they complete. The differences in the organisation of training may result in differences in the physiological stress placed on players. This study aimed to investigate the influence of training organisation on the physiological, metabolic and molecular responses to soccer-specific intermittent exercise in skeletal muscles. In Chapter 3, the physical demands of professional soccer training were examined by quantifying the physiological loads and work-rate profiles of elite players throughout the programmed pre-season and in-season training for a one week period. The physiological loads in pre-season were significantly higher than those in the in-season period (p < 0.05). Similar activity profiles were, however, observed during each training period irrespective of the time of the year. These findings demonstrate that pre- season training was more intensive than in-season training though these differences were not linked to changes in the activity patterns during sessions. Technical/tactical training seems to be an important component in increasing the physiological strain observed in pre-season training. This study also indicates that soccer training seems to elicit different demands to those associated with match-play. In Chapter 4, a laboratory-based soccer-specific training simulation (LSSTS) was devised on a motorized treadmill. Attempts were made to re-create both similar overall exercise intensities and patterns of discrete activity observed in training. The validity of this protocol was evaluated by comparing the physiological responses of professional players with those of healthy subjects who completed the LSSTS. Physiological measurements such as mean HR and % of HRmax associated with the simulation were similar to those obtained in the actual training session. These data suggest that the protocol is suitable in re-creating a soccer-specific training session in the laboratory. This protocol is, therefore, sufficient to use in investigations to study the physiological responses and the molecular adaptations of skeletal muscle to soccer-specific intermittent exercise. In Chapter 5, the effect of a single bout of soccer-specific intermittent exercise on metabolic stress and acute molecular responses associated with mitochondrial biogenesis was investigated in human skeletal muscle. The LSSTS was utilised as the sports-specific exercise protocol. The levels of blood metabolites and muscle glycogen were significantly altered during and after exercise (p < 0.05). Simulated soccer-specific training also acutely activated the expression of PGG-1a mRNA in human skeletal muscle (p < 0.05). There was, however, no significant change in the phosphorylation of AMPK and p38MAPK. This would suggest that the global effect of soccer-specific intermittent exercise on aerobic performance may be partly mediated by adaptations associated with mitochondrial biogenesis in skeletal muscle. ' In Chapter 6, the effect of prior soccer-specific training on the physiological, metabolic and molecular responses to a subsequent bout of soccer-specific intermittent exercise was evaluated. Two experimental trials (BETWEEN DA Y trial, one bout of soccer-specific intermittent exercise in a day Vs WITHIN DA Y trial, two consecutive bouts of soccer-specific intermittent exercise performed in a day) were completed on two separate occasions. There were significant increases in physiological responses during the second bout of exercise in the WITHIN DAY trial, compared to those obtained in the, BETWEEN DAY trial (p < 0.05). A more pronounced increase in NEFA and glycerol was observed in the WITHIN DAY trial compared with the BETWEEN DAY trial post-exercise following the second bout of exercise (p < 0.05). The expression of PGC-1a mRNA significantly increased following exercise compared to pre- and post-exercise values. There was, however, no difference in phosphorylation of AMPK and p38MAPK and the expression of PGC-1a mRNA between either trial. Based on these findings, it would seem that different approaches to training organisation may be more important for the acute physiotoqlca: responses to soccer-specific intermittent exercise than the molecular changes underpinning chronic adaptations.