The body has several different muscle fibre types which can be broadly classified into fast-twitch (type II) and slow-twitch or type I (endurance) fibres.

Both muscle fibre types use all three energy systems to produce ATP-PC and anaerobic glycolytic system,while slow twitch fibres use mainly the aerobic system.Everyone is born with a specific distribution of muscle fibre types.The proportion of fast-twitch fibres to slow-twitch fibres can vary quite considerably between individuals.
For Example…

Top sprinters have a greater proportion of fast-twitch fibres than average and thus can generate explosive power
and speed.,on the other hand,have proportionally more slow-twitch fibres and better able to develop aerobic power and endurance.