AFL football is an endurance sport requiring continual motion for 4 quarters of approx 30mins duration and the aerobic requirement of oxygen to satisfy primary ATP production for muscle fuel (and subsequent secondary lactic acid conversion to fuel) is the requirement of slow twitch muscle fibres. Anaerobic fast twitch muscle fibres fatigue and fail too quickly to be relied on for more than a few sprints but are none-the-less are still an integral requirement in the sport.

What was that? Why does it and why? So you want us to answer twice with the same reason, sorry I'm confused, my head hurts.

Because that system is the one where it is of submaximal intensity (less than 75%) and has a duration lasting longer than 30 minutes as the other 2 systems the anerobic is 10-75 seconds at almost maximal intensity where as the atp-pc system lasts 10 seconds

Sorry what? Got an essay question have we?