This thesis includes four main chapters that investigate the use of speeded video as a method of decision-making training. Six different video speeds were tested using a video-based decision-making task, to gain a thorough understanding of the effects of video speed on different levels of expertise in Australian football, particularly, the mechanisms which drive expert performance. The significant difference in performance between elite and sub-elite at the 1.5 speed indicated this to be a potential training speed for elite athletes.