If you were running a marathon which type of muscle fibers would be most useful to you?

slow-twitch

Slow twitch muscle fibres: Contract slowly, but keep going for a long time. Fast twitch muscle fibres: Contract quickly, but rapidly get tired. Endurance or speed. Slow twitch muscle fibres are good for endurance activities like long distance running or cycling. They can work for a long time without getting tired

not sure if this what   you'r looking for would be percent composition