The importance of post-exercise recovery nutrition has been well described in recent years leading to its incorporation as an integral part of training regimes in both athletes and active individuals. Muscle glycogen depletion during an initial prolonged exercise bout is a main factor in the onset of fatigue and thus the replenishment of glycogen stores is central for post-exercise recovery. Nevertheless, nutritional recommendations, particularly related to the precise nutrient amount/type to optimise short-term (2-6 h) recovery remain incompletely elucidated. Furthermore, the available nutritional guidelines to maximise muscle glycogen availability within limited recovery are provided under the assumption that similar fatigue mechanisms (i.e. muscle glycogen depletion) are involved during a repeated exercise bout, yet this has never been established. One strategy with the potential to accelerate muscle glycogen resynthesis and/or functional capacity is the co-ingestion of protein with carbohydrate. Notwithstanding this, there is outstanding need to establish the influence of carbohydrate-protein ingestion on recovery from running exercise. Beyond the acute post-exercise period, protein ingestion following exercise is known to increase muscle protein synthesis and thus modulate exercise-induced training adaptation. However, whether post-exercise protein ingestion increases the magnitude of running-based endurance training adaptation has not been determined. The collection of work presented in this thesis provides evidence that the availability of muscle glycogen at the end of recovery determines the capacity for repeated exercise such that muscle glycogen depletion is shown to be a major determinant of fatigue during this bout. Moreover, the present work suggests that energy intake per se and not macronutrient composition (i.e. the addition of protein) determines maximal muscle glycogen resynthesis rate and the capacity for repeated exercise. The final experimental chapter in this thesis also provides some evidence for the potential role of post-exercise protein ingestion in amplifying cardiovascular training adaptation through an increase in plasma albumin content in response to six weeks of prescribed endurance training when compared to an energy-matched carbohydrate supplement.
|Date of Award||4 Apr 2016|
|Supervisor||James Betts (Supervisor) & James Bilzon (Supervisor)|